Chapter I: Edible Plums (3)

The writer has seen only herbarium specimens of this plant and has taken the description given from European texts. According to Schneider the species has been divided into two varieties by the Italian botanists. _Prunus cocomilia typica_ having oblong-ovate fruit and _Prunus cocomilia brutia_ having round fruit. Schneider holds also that _Prunus pseudoarmeniaca_ Heldr. and Sart.[82] from Epirus and Thessaly is a variety of _Prunus cocomilia_ differing chiefly in having more pointed leaves and smaller oblong-roundish red plums. The same author puts in this species still another plum, a hairy-leaved form from Thessaly which he calls _Prunus cocomilia puberula_. He places here also _Prunus ursina_ Kotschy[83] which differs only in minor respects from the species, chiefly in having violet-red fruit though Boissier[84] mentions a yellow-fruited plum which he calls _Prunus ursina flava_. The last named plums come from Lebanon and North Syria.

=6.= =PRUNUS CERASIFERA= Ehrhart[85]

=1.= Ehrhart _Beitr. Nat._ =4=:17. 1789. =2.= Hooker _Brit.
Fl._ 220. 1830. =3.= Koch, K. _Dend._ =1=:97. 1869. =4.= Koch,
W. _Syn. Deut. und Schw. Fl._ =1=:727. 1892. =5.= Bailey
Cornell Sta. Bul. =38=:66. 1892. =6.= Schneider _Handb. Laubh._
=1=:632. 1892. =7.= Schwarz _Forst. Bot._ 339. 1892. =8.=
Dippel _Handb. Laubh._ =1=:633. 1893.

_P. domestica myrobalan._ =9.= Linnaeus _Sp. Pl._ 475. 1753.
=10.= Seringe _DC. Prodr._ =2=:538. 1825.

_P. myrobalan._ =11.= Loisleur _Nouv. Duham._ =5=:184. 1812.
=12.= Koehne _Deut. Dend._ 316. 1893.

Tree small or a tree-like shrub, seldom exceeding twenty-five
feet in height; branches upright, slender, twiggy, unarmed or
sometimes thorny; branchlets soon glabrous, becoming yellow or
chestnut-brown; lenticels few, small, orange in color, raised.

Winter-buds small, obtuse, short-pointed, pale reddish-brown;
leaves small, short-ovate, apex acute, base cuneate or rounded,
thin, membranaceous, texture firm, light green, nearly glabrous
on both surfaces at maturity, though hairy along the rib on
the lower surface, margins finely and closely serrate; petiole
one-half or three-quarters of an inch long, slender, usually
glabrous, glandless.

Flowers large, three-quarters of an inch in diameter, expanding
very early or mostly with the leaves; calyx-lobes lanceolate,
glandular, reflexed; petals white, sometimes with a blush,
ovate-oblong or orbicular, the base contracted into a claw;
borne singly, sometimes in pairs, in cymes on long, slender,
glabrous peduncles.

Fruit small, one-half inch or a little more in diameter,
globular or depressed-globular, cherry-like, red or yellow;
skin thin and tender; flesh soft, juicy, sweet and rather
pleasantly flavored; stone oval, short-pointed at both ends,
somewhat turgid, ridged on one suture and grooved on the other.

_Prunus cerasifera_, the Cherry plum, first came to notice in pomological literature as the Myrobalan plum, a name used as early as the last half of the Sixteenth Century by Tabernæ-Montanus and given prominence in the _Rariorum Plantarum Historum_, published by Clusius in 1601. Why applied to this plum is not known. Myrobalan had long before been used, and is still, as the name of several plum-like fruits of the East Indies, not of the genus Prunus, which are used in tanning, dyeing, ink-making and embalming. Until Ehrhart gave it the name _Prunus cerasifera_ in 1789 it was known as the Myrobalan plum by botanists, some of whom, and nearly all horticulturists, have continued the use of the name until the present time.

Not a few of the botanists who have used Myrobalan for this plum have called it a botanical variety of _Prunus domestica_. Among these were Linnaeus and Seringe. Others, as Loisleur and Poiteau, have preferred the name for the species as distinguished by Ehrhart.

Many of the early botanists, as Tournefort in 1700, Ehrhart in 1701, Loudon in 1806 and Loisleur in 1812, gave the origin of the Cerasifera plums as North America, but upon what authority does not appear. On the other hand many European botanists, including Linnaeus, gave the habitat as Europe or Asia. The supposition that this plum came from North America hardly needs discussion. The plum flora of this continent has been well enough studied so that it can be said that no plant that could by any possibility be the Cerasifera plum grows on this side of the Atlantic. Neither does it seem logical to consider this an off-shoot of _Prunus domestica_, for fruit and tree-characters are distinctly different, and for a member of the genus Prunus are remarkably constant. Moreover, there is abundant evidence to show that this is a distinct species and that its nativity is in the Turkish and nearby countries in Europe and Asia and that there it has been in cultivation for a long time.

It is very significant that in the old herbals and botanies a frequent name of this fruit is “the Turkish plum.” But more specific and almost conclusive proof is that two forms of plums belonging to this species are known to come from the Caucasus region. _Prunus divaricata_[86] is now considered by some botanists to be a synonym of _Prunus cerasifera_ and by others to be a botanical variety of the last named species. Ledebour, who named it, found it in the Trans-Caucasian region. It differs from the type only in having much divided, wide-spreading and nearly prostrate branches. The Pissardi plum, a purple-leaved form of this species, originated in Persia. A plum now growing in the Arnold Arboretum raised from seed from Turkestan, presumably from wild stock, is identical with plants of Cerasifera of European origin. And, according to Schneider,[87] this plum is known in the wild state in Caucasus, Trans-Caucasus, northern Persia and Turkestan.

The Cerasifera plums are small trees, usually upright but in some forms with spreading branches which are commonly unarmed, glabrous and brownish in color. The leaves are ovate and smaller and thinner and with more finely serrate margin than those of the Domestica plums. It blooms prolifically and bears large, white, single or paired flowers, making a most beautiful tree when in flower. The fruit is small, round, and cherry-like, from half an inch to an inch in diameter, usually red but sometimes yellow. The flesh is soft, sweetish or sub-acid and poor. The stone is turgid, smooth and pointed. The species is variable in nearly all tree-characters, and were it not surpassed by other plums for its fruit there would undoubtedly be a great number of varieties cultivated for the markets. There are, however, but few cultivated Cerasiferas, only nineteen being described in _The Plums of New York_. It is very generally distributed wherever plums are grown, because of the use to which it has been put as stocks for other species. For this purpose it is held in high esteem the world over. In the nurseries of New York it is now used more than any other stock and it is common to find it fruiting here and there from plants set for or used as stocks. In fact practically all the cultivated varieties have arisen as survivals of plants meant for stocks. It is almost certain that the Cerasifera, or Myrobalan, as it is universally known by horticulturists, dwarfs the cion and that it is not equally well suited to all varieties; but it does not “sprout” as badly as some other stocks, is adapted to many soils, and the young trees grow well and are rapidly budded, giving at the start a strong and vigorous orchard tree.

The Cerasifera plums are handsome trees. The foliage is a fresh and beautiful green and whether covered with a mass of flowers or loaded with red or yellow fruit these plums are as handsome as any of our cultivated fruit trees, and as desirable for ornamentals.

The hardiness, thriftiness, freedom from disease and adaptability to soils make the species desirable for hybridizing. A number of breeders of plums have made use of it with some indications of a promising future, several interesting hybrid offspring of this species being described in _The Plums of New York_.

The small number of varieties of Cerasifera cultivated for their fruit indicates that but little can be expected from this species by plum-growers, since so little has come from it in the shape of edible fruits, though it has been under general cultivation for over three hundred years, at least, as an ornamental and as a stock. Several valuable groups of ornamentals have arisen from Cerasifera, of which the following are most notable:—

In 1880 M. Pissard, gardener to the Shah of Persia, sent to France a purple-leaved plum which proved to be a form of _Prunus cerasifera_. To this plum Dippel[88] gave the name _Prunus cerasifera atropurpurea_, while horticulturists very generally call it _Prunus pissardi_. A close study of the purple-leaved plum reveals no character in which it differs from the species except in the color of foliage, flowers and fruit; the leaves are purple, as are also the calyx and peduncles of the flowers, while the fruit is a dark wine-red. These are but horticultural characters and do not seem to be of sufficient importance to establish for this plant a botanical variety. This view is strengthened by the fact that Jack[89] reports that seeds from the purple-leaved plum have produced plants which agree in all essential particulars with the species; while Kerr[90] has grown a purple-leaved plum from a variety of _Prunus cerasifera_.

Besides this well-known purple-leaved plum nurserymen offer _Prunus pendula_, a weeping form; _Prunus planteriensis_, bearing double white and red flowers; _Prunus acutifolia_, a plum with narrow, willow-like leaves; _Prunus contorta_, characterized by twisted, contorted foliage; _Prunus elegans_, _Prunus gigantea_, and a variety with yellow and another with variegated leaves, etc. All of these are probably horticultural varieties of _Prunus cerasifera_ though some of them cannot be classified with surety.

Schneider[91] calls _Prunus dasycarpa_ Ehrhart,[92] the _Prunus armeniaca dasycarpa_ of Borkhausen,[93] a cross between _Prunus cerasifera_ and _Prunus armeniaca_, one of the apricots.

=7.= =PRUNUS MONTICOLA= K. Koch

=1.= Koch, K. _Ind. Sem. Hort. Berol._ App. 1854. =2.=
Schneider _Handb. Laubh._ =1=:632. 1906.

Plant shrub-like, slender, upright, scarcely thorny, new wood
more or less olive-brown. Buds short, ovate; leaves roundish or
cuneiform, base oblong-ovate, point drawn out, main nerves over
six on both sides, the serrations coarse and uniform in size,
always glabrous. Flowers mostly in twos; borne on long, slender
peduncles; calyx usually glabrous; petals white, odor slight;
stamens thirty or more. Fruit small, roundish-oblong, red;
stone ovoid, pointed at one end, somewhat turgid.

_Prunus monticola_ is described by the above authors as a shrub-like plum from Asia Minor and Armenia having, so far as can be learned from European texts, little or no horticultural value. The herbarium specimens seen by the writer indicate that this species is closely related to _Prunus cerasifera_. The description of the species is abbreviated from Schneider.

=8.= =PRUNUS TRIFLORA= Roxburgh

=1.= Roxburgh _Hort. Bengal_ 38. 1814. =2.= Ibid. _Fl. Indica_
=2=:501. 1824. =3.= Schneider _Handb. Laubh._ =1=:627. 1892.
=4.= Bailey _Cornell Sta. Bul._ 62. 1894. =5.= Waugh _Plum
Cult._ 42. 1901.

_P. domestica_. =6.= Maximowicz _Mel. Biol._ =11=:678. 1883.

_P. hattan_ Tamari. =7.= Bailey _An. Hort._ 30. 1889.

_P. communis._ =8.= Forbes and Hemsley _Jour. Linn. Soc._
=23=:219. 1886-88.

_P. japonica_ of horticulturists (not _P. japonica_ of
Thunberg).

Tree twenty to thirty feet in height, vigorous; trunk six
to twelve inches in diameter, straight; bark thick, rough,
numerous corky elevations especially on the branches,
reddish or cinnamon-brown, peach-like; branches long,
upright-spreading, much forked, brash and often splitting at
the forks; branchlets thick, straight, glaucous and glabrous,
at first light red, growing darker the second year; lenticels
few or many, usually small but conspicuous, light in color.

Winter-buds small and obtuse, free or appressed; leaves borne
abundantly, small or of but medium size, oblong-obovate, point
acuminate or abrupt, prominent, base rounded, firm, thin,
membranaceous, margins finely and closely serrated, sometimes
in two series, teeth usually glandular; upper surface bright
green, glabrous, lower surface dull, whitish, glabrous or
slightly pubescent on the veins; veins pronounced; petioles
one-half inch in length, stoutish, tinged with red; glands few
or several, usually globose, greenish; stipules lanceolate,
very narrow, one-half inch long, caducous.

Flowers expanding early, before, with or sometimes after the
leaves, first of the plum blossoms to appear, very abundant,
three-quarters of an inch in diameter; usually three springing
from each flower-bud, often in dense clusters on lateral spurs
and lateral buds on one-year-old wood; calyx-tube green,
glabrous, campanulate or obconic; calyx-lobes acute to obtuse
glandular-serrate, erect, glabrous or pubescent; petals white,
oval, entire or crenate, with a short claw or tip; stamens
about twenty-five, shorter than the petals; anthers yellow,
sometimes tinged with red; pistils glabrous, longer than the
stamens; pedicels one-half inch long, slender.

Fruit varying greatly in season, from very early to late;
large, from one to two inches in diameter, globular,
heart-shaped or often somewhat conical; cavity deep; apex
conspicuously pointed; suture usually prominent; color varies
greatly but usually a bright red or yellow, never blue or
purple, lustrous, with little or no bloom; dots small,
numerous, usually conspicuous; skin thin, tough, astringent;
stem one-half inch in length; flesh red or more often yellow,
firm, fibrous, juicy; quality variable, of distinct flavor,
usually good; stone clinging tenaciously or nearly free, small,
rough or lightly pitted, oval to ovate, one edge grooved, the
other ridged.

A study of the botanical characters of the many Triflora plums under cultivation fails to show any lines of cleavage whereby the species can be divided. Of plums commonly grown in America it is not very closely related to any unless it be _Prunus simonii_. There are several plums from eastern and central Asia with which we are not at all familiar in America that may show relationship with _Prunus triflora_, chief of which are _Prunus ichangana_ Schneider,[94] _Prunus thibetica_ Franchet[95] and _Prunus bokhariensis_ Royle,[96] the last a cultivated plum from northern India. These, in herbarium specimens, have some characters reminding one of _Prunus triflora_, others of _Prunus domestica_ and still others, of _Prunus cerasifera_.

The Triflora, or Japanese,[97] plums are now cultivated in all parts of the world where plums are grown; yet outside of Japan and China they have been grown for their fruit less than half a century. Despite the fact that these plums have been grown in Asia for several centuries the wild form is not known. Indeed, there are doubts in the minds of some as to whether it constitutes a distinct species, Maximowicz, an authority on the flora of Japan, among others, holding that it is but a form of _Prunus domestica_. Roxburgh in naming it gave but little definite information in regard to the species, but the herbarium specimens of his in the Kew Herbarium are readily identified as identical with our Japanese plums.[98] The confusion between _Prunus triflora_ and _Prunus domestica_ seems needless, as the points of difference between these two species are several and very distinct and constant, the resemblances between _Prunus triflora_ and some of the American species being much closer. So, too, the effort, sometimes made, to make more than one species out of _Prunus triflora_ is straining a point, for though the types under cultivation vary considerably yet the variations are not greater than between varieties of other species of the genus Prunus.

_Prunus triflora_ is almost certainly a native of China. According to Georgeson and Sargent, who have made extensive botanical explorations in the forests of Japan, there are no indigenous plum trees in that country. Dr. K. Miyake, botanist at the Agricultural College of the Imperial University, Tokyo, Japan, writes to this Station,[99] that _Prunus triflora_ does not grow wild in Japan but was introduced there from China from two to four hundred years ago. Bretschneider[100] in his treatise on _The Study and Value of Chinese Botanical Works_ says that the plum has been cultivated from ancient times in China and this indicates that the original habitat was in that country. Mr. F. N. Meyer, Agricultural Explorer for the United States Department of Agriculture, who has made extensive agricultural explorations in China, writes[101] that he has seen many trees of _Prunus triflora_ cultivated in the Chekiang Province and also about Canton but that he had not found the species growing wild. Roxburgh says[102] that the shrub had been “received from China into our gardens in Bengal.” Forbes and Hemsley[103] state that varieties of this plum are cultivated in China and that it occurs in the wild state in the mountains near Peking as well as on the Tsunglin range in Shensi and Kansu. These writers are, however, uncertain as to where it is truly indigenous.

While the above and practically all evidence points to China as the original home of _Prunus triflora_ it is likely that the habitat of the species cannot be accurately determined until western and southwestern China have been explored by botanists, these regions as yet being almost unknown to foreign scientists.

Notwithstanding the illustrious work of Kaempfer, Thunberg, Siebold and Fortune in sending to Europe the choicest plants of Japan and China, _Prunus triflora_ seems to have reached the Old World through America at a very recent date. At least the species was not cultivated for its fruit in Europe until introduced from the United States as Japanese plums, and even yet they are but barely known in European orchards. The species was introduced into this country from Japan about 1870 by a Mr. Hough of Vacaville, California. According to Bailey,[104] who has given much attention to these plums, Mr. Hough obtained his trees from a Mr. Bridges, United States Consul to Japan. John Kelsey, Berkeley, California, produced the first ripe fruit of the Triflora plums in America in 1876 and 1877, and impressed by their value began recommending them. Owing to Mr. Kelsey’s efforts the propagation of these plums was begun on a large scale about 1883 by W. P. Hammon & Co., of Oakland, who commemorated Mr. Kelsey’s labors by naming the plum after him. The success of the Kelsey started the importation and origination of varieties and a veritable boom in Japanese plums was soon under way.

This fruit is a most valuable addition to our pomology, no less than ninety-two varieties now being under cultivation in America. At first it was thought desirable only for the southern states, but it proved to be nearly as hardy as the Domestica plums in the northern states and was soon widely distributed north and south. Beyond question it has suffered from over-praise, which has led to over-planting. As was of necessity the case, many untested and worthless varieties were offered fruit-growers, and these, with the failure of some of the extravagant claims for the really meritorious varieties, have given the Triflora plums a bad reputation with many fruit-growers. Now we have cultivated plums of this species for forty years and there has been time for the excitement of their discovery and the consequent reaction to abate making it possible to arrive more nearly at their true place in pomology.

The plums of this species possess several striking features that commend them to fruit-growers. Undoubtedly the most valuable attribute of the Triflora plums as cultivated fruits is their wide range of adaptability. All must admit that this group of varieties is less valuable than the Domestica varieties where both succeed, but the Triflora plums are adapted to a much wider range of country and of conditions than the Domesticas. But even where both types of plums succeed the newer plum introduces several very desirable features quite aside from additional variety which the many distinct sorts furnish. Thus, as a species, the Trifloras are more vigorous, productive, earlier in coming in bearing and more free from diseases, especially black-knot and leaf-blight, than the Domestica plums. The Trifloras are also less subject to curculio than most of the native and European species. They keep longer and ship as well as the better known Europeans. As compared with native varieties the plums from Japan are larger, handsomer and better flavored and keep and ship better. Some disadvantages are that they blossom so early as to be often caught by spring frosts; they are quite subject to brown-rot; for most part they are tenacious clingstones; the species, all in all, is less hardy to cold than the Domestica plums; lastly, they are inferior in quality to the varieties from Europe. The last fault is so serious that, though the average for the Triflora plums is high, making them unquestionably more desirable inhabitants of the orchard than any of the native species, they cannot compete with the Domesticas where the two types can be equally well grown.

The botanical differences between these Asiatic plums and those from Europe and America are most interesting. In 1859 Asa Gray called attention to the striking resemblances between the east coast floras of Asia and America. The Triflora plum is one of the plants which furnishes substantial evidence of this similarity and of the dissimilarity of the east and west coast floras of the two hemispheres. In general aspect the trees of the Triflora plums in summer or winter are much more like those of the American species than like those from Europe or West Asia; so, too, the fruits are more alike in appearance and in quality, and the peach-like foliage of the Trifloras might easily be mistaken for that of some of our varieties of Hortulana or Munsoniana. In the manner in which the buds are borne and in vernation the resemblance of the Oriental species to the Americanas, Hortulanas and Munsonianas is again most striking. In Asiatic and American species the buds are borne in twos and threes, while in the European species they are more often single or double.

The importance of this similarity of the Triflora plums to the most common American species is seen when Gray’s reason for the likenesses between the two floras is considered. This, briefly, is that similar types of post-glacial plants should persist in areas having like geographical positions and like climates; hence east-coast plants in one hemisphere should be expected to be similar to those of the east coast of the other hemisphere and the same with the west coast. Triflora plums are near of kin to American plums, then, because they have been evolved under similar conditions. This is a reason why these plums from Japan are adapted to so wide a range of country in America, and why, too, they are so free from the fungus troubles which attack European plums, but from which American plums suffer but little.

As might be expected from their nearness of kin the Triflora plums hybridize readily with the American species and especially with the Hortulanas and Munsonianas, the species they most resemble. Unfortunately an amalgamation of the Oriental plums with the Americanas is not so easily accomplished and that with the Domesticas is still more difficult. Hybrids with _Prunus simonii_ are easily made and the progeny as a rule have much merit. Hybrids of the Trifloras with our native species give most promising results, a number of them being described in _The Plums of New York_. The fact that the Trifloras have been cultivated for several centuries, at least, means in their hybridization with American species that there is an amalgamation of domesticated characters with the similar but wilder characters of our native species.

It has been very difficult to establish a satisfactory nomenclature for the Triflora plums now grown in America. In spite of the excellent work of Berckmans,[105] Bailey[106] and Waugh,[107] in bringing order out of what was at one time utter confusion, there is still a great deal of uncertainty as to the identification of some varieties. The confusion began with the first extensive importation of these plums from Japan when names which the Japanese applied to classes or groups or the localities from which the plums came were made to apply in America to definite varieties. Many of the names under which the plums were imported have had to be dropped and the varieties boldly renamed. Another source of confusion has been that these, of all plums, seem most variable under changed conditions. Local environment in many instances in America changes somewhat the habit and appearance of varieties, making it difficult to decide whether two or more specimens of the same sort from different localities are identical varieties or distinct. Curiously enough, too, the trees of some varieties of plums seem to bear unlike fruit in different years, especially in the matter of time of ripening; that is, trees of some varieties do not always ripen their fruit in the same sequence, being earlier than another variety one year and possibly later the next. All fruits are more or less variable in this respect, but the Triflora plums are remarkably so, a fact that has added to the confusion in their nomenclature, since it adds to the difficulty of identifying varieties.

The cultivated varieties of _Prunus triflora_ are also very diverse as regards tree-characters, especially as to vigor, hardiness and time of maturity of the fruit. The differences seem to be horticultural or those that come from cultivation, rather than botanical. Indeed, it seems impossible to place the numerous varieties in horticultural groups that are marked with any great degree of definiteness. A distinction of groups based on color is sometimes made, but the one character is insufficient to have classificatory value. In Japan, according to Georgeson, a division of the species is made with shape as the line of division. He says[108] “The round plums are designated by the term botankio, while those of an oval or pointed shape are called hattankio.” The varieties are sometimes loosely grouped into yellow and red-fleshed sorts. A serviceable classification would have to be founded on several or a considerable number of characters. Such a classification at present is impossible.

=9.= =PRUNUS SIMONII= Carrière

=1.= Carrière _Rev. Hort._ 111. 1872.[109]

Tree small, of medium vigor, upright, dense, hardy except in
exposed locations, unproductive; branches stocky, long, rough,
thickly strewn with small lenticels; branchlets slender, long,
with internodes of medium length, reddish, glabrous; leaf-buds
intermediate in size, short, obtuse, free.

Leaves folded upward, oblong-lanceolate to obovate, peach-like,
narrow, long, of medium thickness; upper surface dark green,
smooth, shining, lower surface pale green, not pubescent, with
prominent midrib; margin slightly crenate; petiole short,
thick, faintly tinged red, often with four large globose glands
on the stalk.

Flower-buds numerous on one-year wood although found on spurs
on the older wood; flowers appearing very early, semi-hardy,
small, pinkish-white; borne singly or in pairs, often defective
in pollen.

Fruit maturing early; one and three-quarters by two and
one-quarter inches in size, strongly oblate, compressed;
cavity deep, wide, flaring, regular, often slightly russeted;
suture variable in depth, frequently swollen near the apex
which is flattened or strongly depressed; dark red or
purplish-red, overspread with waxy bloom; dots numerous,
small, dark colored, with russet center, inconspicuous; stem
thick, characteristically short being often one-quarter inch
long; skin of medium thickness, tough, bitter, adhering to the
pulp; flesh rich yellow, medium juicy, tough, firm, very mild
sub-acid with a peculiar aromatic flavor; of fair quality;
stone clinging, about seven-eighths inch in diameter, roundish,
flattened to rather turgid, truncate at the base, tapering
abruptly to a short point at the apex, with characteristic
rough surfaces; ventral suture narrow, acute or with distinct
wing; dorsal suture very blunt or acute, not grooved.

All that is known of the history and habitat of this species is that it came from China in 1867 having been sent to the Paris Museum of Natural History by Eugene Simon, a French consul in China. The spontaneous form has not as yet been found. The general aspect of the tree is more that of the peach than the plum and the drupes are as much like apricots or nectarines as plums but when all characters are considered the fruit can better be classed with the plums than with any of the other stone-fruits named.

_Prunus simonii_ has been widely grown in America both for its fruits and as an ornamental, but it cannot be said that it has become popular for either purpose and only one variety of the species is now under cultivation. As a food product the plums lack palatability and as ornamentals the trees are subject to too many pests. _Prunus simonii_ has been successfully hybridized with _Prunus triflora_ and as secondary crosses its blood has been mingled with that of some of the native species as well. Most of its hybrid offspring have more value than the parent, nearly all of them lacking its disagreeable taste. According to an article published in _Revue Horticole_[110] a new form of the _Prunus simonii_ was produced in 1890 from a bud sport, the fruit of which is elongated, a little cordate, slightly unequal, and grooved on one side. So far as can be learned this sport has no very decided merits as a horticultural plant.

=10.= =PRUNUS AMERICANA= Marshall

=1.= Marshall _Arb. Am._ 111. 1785. =2.= Eaton and Wright _N.
Am. Bot._ 377. 1840. =3.= Torrey and Gray _Fl. N. Am._ =1=:407.
1840 (in part). =4.= Torrey _Fl. N. Y._ =1=:194. 1843 (in
part). =5.= Emerson _Trees of Mass._ 449. 1846. =6.= Nuttall
_Silva_ =2=:19. 1846. =7.= Darlington _Fl. Cest._ Ed. =3=:72.
1853. =8.= Torrey _Pac. R. Rpt._ =4=:82. 1854. =9.= Curtis
_Rpt. Geol. Surv. N. C._ 56. 1860. =10.= Ridgway _Proc. U. S.
Nat. Mus._ 65. 1882. =11.= Sargent _10th Cen. U. S._ =9=:65.
1883 (in part). =12.= Watson and Coulter _Gray’s Man._ Ed.
=6=:151. 1889 (in part). =13.= Coulter _Cont. U. S. Nat. Herb._
=2=:102. 1891. =14.= Sargent _Silva N. Am._ =4=:19, Pl. 150.
1892. =15.= Rydberg _Cont. U. S. Nat. Herb._ =3=:156. 1895.
=16.= _Ibid._ =3=:494. 1896. =17.= Waugh _Vt. Sta. Bul._
=53=:59. 1896. =18.= Ibid. _Vt. Sta. An. Rpt._ =10=:100.
1896-7. =19.= Chapman _Fl. Sou. U. S._ 130. 1897. =20.= Bailey
_Ev. Nat. Fr._ 182, fig. 1898. =21.= Waugh _Vt. Sta. An. Rpt._
=12=:231. 1899. =22.= Mohr _Cont. U. S. Nat. Herb._ =6=:551.
1901. =23.= Bailey _Cyc. Am. Hort._ 1448 fig. 1901. =24.=
Rydberg _Fl. of Colo._ 193. 1906.

Tree attaining a height of thirty feet, slow but strong in
growth, often shrubby; trunk thick, sometimes a foot in
diameter, short, bearing the head at three to five feet; bark
one-half inch thick, dark grayish-brown, outer surface rough,
shaggy with large scales, with age becoming smoother, giving
a characteristic aspect; branches spreading, crooked, long,
rigid, but often pendulous at the extremities, more or less
thorny, with lateral, spinescent branchlets; branchlets light
green, usually glabrous, sometimes much or little tomentose,
at first becoming brownish and later tinged with red; lenticels
numerous, large and distinct.

Winter-buds medium in size, short, acute, appressed,
reddish-brown; leaves large, obovate, oblong-obovate, or oval,
acuminate at the apex and usually rounded at the base, thin and
firm in texture, becoming somewhat coriaceous; margins sharply
serrate, almost incised, often doubly serrate, the coarse and
double serrations characteristic; teeth not glandular; upper
surface more or less roughened, light green, the lower one
glabrous or slightly hairy, sometimes pubescent, coarsely
veined, the midrib grooved on the upper side; petioles slender,
two-thirds inch in length, usually glandless; stipules long,
sometimes three-lobed, falling early.

Flowers expanding after the leaves, large, an inch in diameter,
borne in lateral umbels, two to five-flowered, mostly on
one-year-old wood; pedicels one-half inch long, slender,
usually glabrous; calyx-tube obconic, entire, glandular,
reddish on the outer, green on the inner surface, glabrous;
calyx-lobes acuminate, glabrous on the outer and pubescent
on the inner surface, reflexed; petals white, sometimes with
bright red at the base, rounded and often lanciniate at the
apex, contracted into a long, narrow claw at the base; stamens
about thirty in number, as long as the petals; anthers small,
yellow; pistils glabrous, slender, as long as the stamens;
stigma thick and truncate; anthers and pistils often defective;
when in full flower emitting a disagreeable odor.

Fruit very variable in ripening period; globose, sub-globose,
conical, oval, or sometimes oblique-truncate, usually more
than an inch in diameter, red or rarely yellowish, mostly
dull, with or without bloom; dots pale, numerous, more or less
conspicuous; cavity shallow or almost lacking; suture a line;
skin thick, tough, usually astringent; flesh golden-yellow,
juicy, meaty, fibrous, sweetish, acid and poor but often good
to very good; stone clinging or free, turgid or flattened, the
apex pointed, ridged on the ventral and slightly grooved on the
dorsal suture, surfaces smooth.

As _Prunus americana_ is more carefully studied throughout the great territory it inhabits, undoubtedly one or more sub-species will be described. The plums of this species in the Mississippi Valley are distinguished from the eastern and typical form by fruits having a length greater than the diameter, by a somewhat different aspect of tree and by flatter seeds which are usually conspicuously longer than broad. All of the cultivated varieties come from the western form. The plant of _Prunus americana_ in the dry plain regions in Kansas and Nebraska becomes shrubby in character while on the alluvial bottom lands along the streams in this region it retains the character of a tree. In the southern limit of its range, the leaves of this species are more or less pubescent on the lower surface. As the species occurs throughout western New Mexico, Colorado, Utah, Wyoming, Montana and Manitoba, it differs enough, possibly, from the eastern types to be considered a sub-species, having a wholly different aspect of tree, silvery and somewhat scurfy twigs, smaller, thinner and lighter colored leaves and smaller fruits with more roundish stones.

_Prunus americana_ is the predominating native plum. It is the most widely distributed, is most abundant in individual specimens and has yielded the largest number of horticultural varieties of any of the native species. Because of its prominence and comparatively high degree of permanency of characters it may well be considered the type from which has sprung not only its botanical varieties but several other of the American species. Its variability, too, is shown in its many diverse horticultural varieties, and of its adaptability it may be said that it flourishes on nearly all soils and exposures, and is found wild or cultivated from Maine to Florida and northward from Mexico along the eastern slope of the Rocky Mountains well into Canada. The species was well named by Marshall “Americana.”

This plum has not played nearly as important a part in the pomology of America as its merits would warrant. It seems to have made an impression almost from the first upon the Europeans who settled America, for it is mentioned in nearly all the early records of the food products of the newly found land, yet its cultivation can hardly be said to have begun until the last half of the Nineteenth Century. But the early descriptions of this and other native plums by the colonial explorers, naturalists and botanists, show but little interest in these fruits as subjects for cultivation, and seem to contain almost no prophecies as to the possible development of a new orchard plant from them. It is probable that the Damsons, which were early introduced in America, and the Domesticas, which came at least before the Revolution, proved so adaptable to the part of the New World in which the colonies were planted that this, even though the best of the wild plums, offered small reward in comparison.

It is certain, however, that from the very first, Americana plums were much used by the early settlers as wild fruits, for the histories of all the colonies and states in which plums are found contain innumerable references to wild plums, usually with some expression showing that they were considered makeshifts until the European plums could be grown. Long before white men came to America the possessors of the continent knew and esteemed these fruits of the woods. According to some of the early writers wild plums of this species, since found where the Americanas are dominant, were planted and rudely cultivated by the natives.[111] It is likely, however, that these Indian orchards were more often the result of seeds dropped about camping places and towns rather than regularly planted orchards. It is not improbable that the wide distribution of this species in the Mississippi Valley and the country about and beyond the Great Lakes is due somewhat to the hand of the Indian, of the voyageur and of the missionary of the French regime.

The common names under which this plum passes in the states where it is found as a wild fruit are indicative of the knowledge possessed of it by the people. The Americana is nearly always the wild plum of eastern America. It shares with several other species the names in various parts of the country of Red Plum, Yellow Plum, the Horse and the Hog Plum. In Iowa this is most often the “native plum;” in Indiana it is the Goose plum; in Georgia, the August plum, while in the states bordering on the Gulf it is often called the Sloe.

The domestication of Americana plums is due to the fact that the plums of Europe will not thrive in the Mississippi Valley, the prairie states, nor, for the most part, in the South. The European species are tender both to cold and heat in these regions and they are attacked by those scourges of plum culture, black-knot, leaf-blight and curculio. If, then, the people in the West and South were to have plums at hand when wanted, the wild species had to be brought under cultivation. Where the two will grow side by side it is doubtful if any would choose to grow the Americanas in preference to the Europeans or even for the sake of variety.

The Americana plum was introduced into European gardens at an early date, for references to it are found in the pomological works of the Eighteenth Century, Duhamel having described it in his great work on pomology in 1768, under the name _Prunier de Virginie_, and later Poiteau[112] gives a very good description of it under the name _Prune de la Gallissioniere_. Just how much earlier than these dates it was taken to the Old World cannot be said, but seeds of it are likely to have been taken there by some of the returning explorers of early colonial times. The important fact is that as a cultivated fruit it has made absolutely no headway in competition in Europe with the plums of that continent though it is to be found not infrequently as an ornamental.

The domestication of these plums began less than a century ago, not through direct efforts in breeding them but as the result of the selection of the best of the wild or chance trees found in many widely separated localities. It would be most interesting to follow in detail the introduction of variety after variety of this species into cultivation, giving full credit to the men, many of them pioneers in newly settled countries, through whose efforts the amelioration of the species was begun. But space forbids, and the reader who desires to trace more fully the history and the evolution of these plums must put together the histories of the two or three hundred varieties of Americanas described in the chapters on varieties.

Are the Americanas to compete with the Domesticas, Insititias and Trifloras where all may be grown? It is very doubtful or at least not soon. The Old World plums are so superior, speaking generally, in size, appearance, and flavor, the qualities which appeal to those who eat plums, that the native varieties stand small chance for popular favor. Their place in pomology must long remain the region where the older and more highly developed groups of plums cannot be grown. Though there are now many times more of the Americana plums under cultivation than of the recently introduced Trifloras, the latter are more popular and are likely to remain so in localities where both can be grown.

The range of _Prunus americana_ is seemingly increasing, making it almost impossible to give its present limits. The boundary line of its northern range passes through central New York to central Michigan, southern Wisconsin, Minnesota and South Dakota extending northwestward to Manitoba and reaching its western limit in Utah. It occurs locally southward through Colorado to northern New Mexico. It is rare in Oklahoma and does not occur in Texas, but is represented in Missouri by a pubescent form. East of the Mississippi River the typical species occurs in all of the states from central New York southward to northern Florida. In this great territory it is found in many diverse soils and exposures but responding in all to good soil and congenial environment. In the wild state the Americana plums are most often found along the borders of streams and swamps or in bottom lands where moisture abounds. Sometimes they are found in swamps which may be submerged a part of the year. In spite of a predilection for moist lands, however, the wild plants are not infrequently found on comparatively dry uplands, seeming to prefer soils containing considerable lime. The wild trees are usually found in thickets, often of considerable extent.

Under cultivation the range is even greater than for the wild plant. It is only in localities of extreme heat and cold, humidity or aridness, that some of the many Americanas cannot be made to grow under conditions at all favorable for orchards of any of the temperate fruits. So, too, varieties may be found for nearly all soils which permit of cultivation. This freedom from local attachments is one of the chief assets of the species.

The Americana tree is commonly small, often but a bush, and usually with a thick, thorny top. Generally the head attains a height of about fifteen or eighteen feet and sometimes it rises to twenty-five or thirty feet, spreading into many rigid branches which are often pendulous at the extremities. The species may almost always be told by the rough, shaggy, grayish bark, the large, thin, persistent plates of which give a very characteristic shagginess. In the spring the tree is covered with umbelliferous masses of pure white flowers and both at this season and later with its ample foliage or showy fruit, the plant is very ornamental. The leaves are large, oval or obovate, thin, dull and veiny, with very jagged margins.

The fruit is reddish or yellowish or a blending of the two with the red varieties predominating. Often the color is more nearly orange than red or yellow—in fact pure yellow fruits cannot be found. Wild or cultivated the fruits of the Americana plums vary greatly in season, size, shape and flavor. In the orchard the period of maturity covers a range of several weeks, beginning in New York in August and ending in October; in the wild, trees in the same thicket may vary as much as three weeks in ripening their fruit. The size of the cultivated sorts is from that of a Damson to that of some of the Gages, the shape being roundish-oval, or quite oval, sometimes oblique and sometimes truncate at one or both ends and often more or less compressed. The wild fruits usually have a pleasant flavor and this is much improved under cultivation so that when fully ripe the flesh of some sorts is sweet and luscious, hardly surpassed, if the skin be rejected, by the best Domesticas. The skin is usually thick, coriaceous, acerb or astringent, and altogether very unpleasant, making with the tenaciously clinging stones the chief defects of these fruits. In some varieties skin and stones are far less objectionable than in others.

The trees of the varieties we have as yet are not very manageable in the orchard. They make a very slow growth and are hard to control, producing at maturity many leaning trunks which are often crooked, as are also the branches which, with the unkempt heads, give an impression of waywardness and wildness. Nearly all of the varieties over-bear and unless thinned the fruits are so small as to be hardly worth harvesting; not infrequently trees die from over-bearing. A few varieties are unfruitful but usually because of defective pollination. Nearly all sucker badly on their own roots, and except in cold regions should be grown on other stocks. In general there are fewer pests to combat with these than with the European plums but yet they are far from being exempt and require on the grounds of this Station quite as much spraying as do other plums.

Waugh, who has given the subject much study, claims that the Americanas are not very strong sexually,[113] chiefly because of defective reproductive organs. He found in extensive examinations that 21.2 per ct. of the pistils were defective, ranging from nothing in some varieties to 100 per ct. in others. More seldom the anthers were defective and the flowers were sometimes proterandrous (the pollen maturing before the pistil is ready to receive it), and that they were rather frequently proterogynous (the pistils receptive before the pollen is mature). Waugh holds that in planting these plums, provision should be made for cross-pollination, and recommends as sorts most suitable for inter-planting for this purpose, other varieties of the same species.

Plant-breeders have not found that this species hybridizes as readily as most of the other cultivated native plums. This is chiefly due to a seeming lack of affinity for other species. Nevertheless there are numerous Americana hybrids, and it is likely that as the high quality of the fruit and the hardiness of the trees become better known they will be used much more for hybridizing.

The Americana plums are all hardy and some of the varieties can be grown as far north as general agriculture is practiced. These, with the Nigras, will probably always be the chief groups for dry, cold regions between the Great Lakes and the Rocky Mountains. They may also be relied upon in the colder parts of New York and New England. The flower-buds as well as the trees are hardy, having been known to withstand a temperature of forty degrees below zero. Goff[114] reports that in the winter of 1896-7 the flower-buds of Domestica varieties on the grounds of the Wisconsin Experiment Station were almost totally destroyed though the minimum temperature recorded was only twenty-three degrees below zero, but the flower-buds of Americana varieties were not at all injured. Since the blossoms open comparatively late there is less damage from spring frosts in this than in most other species even of the natives.

The number of varieties of Americana plums is a testimonial to the merits of the species. There are about 260 varieties of them more or less disseminated. There are many divergent types of these and since all are far from what may be eventually expected from the species the number of varieties will undoubtedly greatly increase and in still other directions. In the meantime the great majority have fallen by the wayside. The weeding-out process seems to be in this case the chief agent of progression. A fault with the varieties now before the public is that many of them are so similar that a difference can hardly be detected. The elimination of the great majority of the varieties of this species now in the catalogs and a much more judicious selection of varieties for future dissemination would relieve pomology of the burden it now carries in the numerous sorts of Americanas.

=PRUNUS AMERICANA MOLLIS=[115] Torrey and Gray

=1.= Torrey and Gray _Fl. N. Am._ =1=:407. 1840. =2.= Sargent
_10th Cen. U. S._ =9=:65. 1883. =3.= Coulter _Cont. U. S. Nat.
Herb._ =2=:102. 1891. =4.= Sargent _Sil. N. Am._ =4=:19. 1892.
=5.= Waugh _Bot. Gaz._ =26=:50. 1898.

_P. americana lanata._ =6.= Sudworth _Nom. Arb. Fl. U. S._ 237.
1897.

_P. lanata._ =7.= Mackenzie and Bush _Trans. Acad. Sci. St.
Louis_ =12=:83. 1902.

_Prunus americana mollis_ is a western and southwestern form of _Prunus americana_, the sub-species being distinguished from the species by the amount and character of the pubescence on the leaves and shoots. The leaves, petioles and shoots of this plum are soft-pubescent, almost tomentose, the tomentum being pale in color and usually very dense; the calyx-lobes are pubescent on both sides and the pedicels are appressed and densely pubescent. According to Bailey, there is a form of this sub-species “with flowers as completely double as those of St. Peter’s wreath, or similar spireas.” This double-flowering plum we have not seen.

It is impossible to give the range of _Prunus americana mollis_ as the woolly-leaved plum of the west gradually passes into the smooth-leaved species of the east and the two forms are not infrequently mixed in the South and Southwest; or possibly it would be better to say that they run into each other though the extreme forms are sufficiently distinct as to be readily mistaken for separate species. It can only be said that it is to be found in the greatest abundance in the region extending from southern Iowa through Missouri. Only two varieties of this plum, Wolf and Van Buren, are in general cultivation, both of which originated in Iowa. In neither fruit nor tree-characters do these differ greatly from the Americana plums.

A plum with pubescent leaves belonging to the Americana series known locally as the Big Tree plum, occurs from western Tennessee, south-westward through the extreme southern portion of Missouri, through Arkansas, southern Oklahoma, extending westward in central Texas, at least, as far as the Colorado River and reaching its southwestern limit in northern Mexico. From specimens of this plum in several herbaria and from studies made of it in the field by W. F. Wight of the United States Department of Agriculture, it would seem that this plum is a distinct species, its chief distinguishing character being the great size attained by the tree. So far as it is known the Big Tree has no cultivated forms unless it be Bilona, supposed to be a hybrid between this species and _Prunus triflora_, now growing on the grounds of F. T. Ramsey, Austin, Texas.

=11. PRUNUS HORTULANA= Bailey[116]

=1.= Bailey _Gar. and For._ =5=:90. 1892. =2.= Sargent _Sil.
N. Am._ =4=:23, Pl. 151. 1892. =3.= Waugh _Vt. Sta. An. Rpt._
=10=:99-105. 1897. =4.= Mohr _Torrey Bot. Club Bul._ =26=:118.
1899. =5.= Bailey _Cyc. Am. Hort._ 1450, fig. 1901. =6.= Mohr
_Cont. U. S. Nat. Herb._ =6=:551. 1901.

_P. americana_, var.? 7. Patterson _List Pl. Oquawka_ 5. 1874.

Tree attaining a height of thirty feet or more, vigorous
in growth; trunk sometimes a foot in diameter; trunk and
branches rough and shaggy becoming furrowed in age; bark
gray-brown, thick and containing deposits of red cork cells
which show as bright red blotches or as thick layers when the
bark is sectioned, these deposits, especially in quantity,
characterizing the species; branches very spreading and open,
twiggy, slender, thorny; branchlets light green at first,
becoming reddish-brown, glabrous and glossy; lenticels few,
large, very coarse, raised, characteristic of the species.

Winter-buds plump, very small, obtuse, appressed; leaves one
and three-quarters inches wide to five inches in length,
long-oval with a tapering, pointed, acuminate apex, peach-like,
base abrupt, texture thin, becoming leathery, margins serrate,
almost crenate, sometimes in a double series, glandular;
upper surface smooth, glossy, glabrous; lower surface light
green, almost glabrous except on ribs and veins which are very
pubescent, with characteristic orange color, midrib grooved
above, rounded below, very prominent; petioles slender, an inch
in length, pubescent on the upper side, tinged with red; glands
two to eight, small, globose, mostly on the petioles.

Flowers expanding after the leaves, blooming later than any
other cultivated plum, three-quarters inch across; odor
disagreeable; clusters borne from lateral buds on one-year-old
wood only, characterizing the species, the fruit-spurs making
a very long growth, more like branches than the spurs of other
species, two to six flowers from a bud; pedicels three-quarters
inch long, very slender, glabrous; calyx-tube narrow,
campanulate, glabrous, green; calyx-lobes narrow, acute,
glandular-serrate, glands red, slightly pubescent on the inner
side, erect; petals ovate, slightly crenate, dentate at the
apex, tapering into long narrow claws; stamens about twenty in
number, yellow; pistils glabrous, equal to or shorter than the
stamens.

Fruit very late in ripening; globose, oval, an inch in
diameter; color varying from shades of red to shades of
yellow; bloom inconspicuous or lacking; dots numerous, small,
conspicuous; suture very shallow or only a line; skin thick,
tough, astringent; flesh golden-yellow, juicy, coarse, fibrous,
firm, flavor mildly sweet, astringent at the pit, strongly
aromatic; quality fair; stone clinging to the flesh, turgid,
long-oval, small, prolonged at the ends, the surfaces rough and
reticulated.

_Prunus hortulana_ as established by Bailey, to quote a part of the original description, “includes a large class of plums represented by Golden Beauty, Cumberland, Garfield, Sucker State, Honey Drop, probably Wild Goose and others.” Unfortunately Bailey later added[117] a number of other plums to the group which the above varieties and some ten or fifteen others comprise, the additions in themselves constituting at least three somewhat distinct groups, and then to account for this omnibus species called it a “brood of natural hybrids.” Waugh supports Bailey’s conclusions[118] and divides the species into four groups of hybrids—the Miner group, the Wild Goose group and the Schley or Clifford group. These, Waugh says, “form an unbroken series from _Prunus americana_ to _Prunus angustifolia_.” The fourth of Waugh’s groups, “comparatively distinct from the others, is made up of such varieties as Wayland, Moreman, Golden Beauty, Reed, Leptune, Kanawha and others.” These plums he designated as the “Wayland group.” This disposition of the plums under consideration leaves _Prunus hortulana_ as the name of only a rather loosely related lot of cultivated varieties. It is probable that neither Bailey nor Waugh, had they seen the material now to be had, would have left the species as they did.