Chapter XXV: Part 25

_Jungermanniaceae Acrogynae._--The plant consists of leafy shoots, the origin of which can be understood in the light of the foliose forms described above. The great majority of existing liverworts belong to this group, the general plan of construction of which is throughout very similar. In Britain thirty-nine genera with numerous species are found. With few exceptions the stem grows by means of a pyramidal apical cell cutting off three rows of segments. Each segment gives rise to a leaf, but usually the leaves of the ventral row (amphigastria) are smaller and differently shaped from those of the two lateral rows; in a number of genera they are wanting altogether. Sometimes the leaves retain their transverse insertion on the stem, and the two lobes of which they consist are developed equally. More often they come to be obliquely inserted, the anterior edge of each leaf lying under or over the edge of the leaf in front. The two lobes are often unequally developed. In _Scapania_ the upper lobe is the smaller, while in _Radula_, _Poretta_ and the _Lejeuneae_ this is the case with the lower lobe. The folding of one lobe against another assists in the retention of water. Pitcher-like structures have arisen in different ways in a number of genera, and are especially common in epiphytic forms (_Frullania_, _Lepidolaena_, _Pleurozia_). In some forms the leaves are finely divided, and along with the hair-like paraphyllia form a loose weft around the stem (_Trichocolea_). The rhizoids spring from the lower surface of the stem, and sometimes from the bases of the leaves. The branches arise below and by the side of the leaves.

The sexual organs may occur on the same or on distinct individuals. The antheridia are protected by leaves which are often modified in shape. The archegonia are borne at the apex of the main stem or of a lateral branch. A single archegonium may arise from the apical cell (_Lejeunea_); more commonly a number of others are formed from the surrounding segments. The leaves below the archegonial group are frequently modified in size and shape, but the chief protection is afforded by a tubular perianth, which corresponds to a coherent whorl of leaves and grows up independently of fertilization. The perianth serves also to enclose and protect the sporogonium during its development. In a number of forms belonging to different groups the end of the stem on which the sporogonium is borne grows downwards so as to form a hollow tubular sac enclosing the sporogonium; in other cases this marsupial sac is formed by the base of the sporogonium boring into the thickened end of the stem. The sac usually penetrates into the soil and bears rhizoids on its outer surface. _Kantia_, _Calypogeia_ and _Saccogyna_ are British forms, which have their sporogonia protected in this way. The sporogonium is very similar throughout the group (figs. 8, 9). At maturity the seta elongates rapidly, and the wall of the capsule splits more or less completely into four valves, allowing the elaters and spores to escape. In the Jubuloideae, which in other respects form a well-marked group, the seta is short and the elaters extend from the upper part of the capsule to the base; at dehiscence they remain fixed to the valves into which the capsule splits. The germinating spore usually forms a short filament, but in other cases a flat plate of cells growing by a two-sided apical cell is first formed (_Radula_, _Lejeunea_). In one or two tropical forms the pro-embryonic stage is prolonged, and leafy shoots only arise in connexion with the sexual organs. In _Protocephalozia_, which grows on bare earth in South America, this pro-embryo is filamentous, while in _Lejeunea Metzgeriopsis_, which grows on the leaves of living plants, it is a flat branched thallus closely applied to the substratum. Other cases of the plant being, with the exception of the sexual branches, apparently thalloid, are on the other hand to be explained as due to the reduction of the leaves and flattening of the stem of a shoot (_Pteropsiella_, _Zoopsis_).

The Acrogynous Jungermanniaceae fall into a number of natural groups, which cannot, however, be followed out here. They occur in very various situations, on the ground, on rocks and stones, on tree trunks, and, in the damp tropics, on leaves. Usually they form larger or smaller tufts of a green colour, but some forms have a reddish tint.

From Strasburger's _Text-book of Botany_.]

_Anthocerotales._--This small and very natural group includes the three genera _Anthoceros_, _Dendroceros_ and _Notothylas_, and stands in [v.04 p.0650] many respects in an isolated position among the Bryophyta. Three species of _Anthoceros_ occur in Britain, growing on the damp soil of fields, ditches, &c. The dark green thallus has an ill-defined midrib, and is composed of parenchymatous cells. In each assimilating cell there is usually a single large chloroplast. The apical region, which has a single initial cell, is protected by mucilage secreted by the mucilage slits, which are small pit-like depressions between superficial cells of the lower surface. Mucilage is also often formed in intercellular spaces within the thallus. Colonies of _Nostoc_ are constantly found living in some of the mucilage slits which then become enlarged. The sexual organs are scattered over the upper surface. The stalked globular antheridia are exceptional in being formed endogenously, and are situated in groups in special intercellular spaces. The superficial layer of cells bounding the cavity does not break down until the antheridia are nearly mature. Occasionally antheridia develop on the surface of shaded portions of the thallus. The necks of the archegonia hardly project above the general surface of the thallus. In structure and development they agree with other Hepaticae, though differences of detail exist. The young sporogonium is protected by a thick calyptra derived from the tissue of the thallus around the archegonium. The sporogonium consists of a large bulbous foot, the superficial cells of which grow out into processes, and a long capsule, which continues to grow for months by the activity of a zone of cells between it and the foot, and may attain the length of an inch and a half. The wall of the capsule is several layers of cells thick, and since the epidermis contains functional stomata and the underlying cells possess chlorophyll it is capable of assimilation. In the centre of the capsule is a strand of narrow elongated cells forming the columella, and between this and the wall spores mixed with elaters are formed from the dome-shaped archesporium, the origin of which has already been described (fig. 4, D). The capsule opens by splitting into two valves from the apex downwards, and the mature spores escape while others are developing in succession below. In _Dendroceros_, which grows as an epiphyte in the tropics, the thallus has a well-defined midrib and broad wings composed of a single layer of cells. The capsule is similar to that of _Anthoceros_, but has no stomata, and the elaters have spirally thickened walls. Some species of _Anthoceros_ agree with it in these respects. _Notothylas_ resembles _Anthoceros_ in its thallus, but the sporogonium is much smaller. In some species, although the columella and archesporium arise in the usual way, both give rise to mingled spores and elaters, and no sterile columella is developed.

_Musci_ (Mosses).

Though the number of species of mosses is far greater than of liverworts, the group offers much less diversity of form. The sexual generation is always a leafy plant, which is not developed directly from the spore but is borne on a well-marked and usually filamentous protonema. The general course of the life-history and the main features of form and structure will be best understood by a brief account of a particular example.

A, Leafy shoot (g) bearing a young sporogonium enclosed in the calyptra (c).

B, Similar plant with an almost mature sporogonium; s, seta; f, capsule; c, calyptra.

C, Median longitudinal section of a capsule, with the seta gradually widening into the apophysis at its base; d, operculum; p, peristome; a, annulus; c, columella; s, archesporium; h, air-space between the spore-sac and the wall of the capsule.

(From Goebel's _Pflanzenmorphologie_, by permission of W Engelmann)]

_Funaria hygrometrica_ is a moss of very common occurrence even in towns on the soil of paths, at the foot of walls and in similar places. The small plants grow closely crowded in tufts, and consist of short leafy shoots attached to the soil by numerous fine rhizoids. The latter, in contrast to the rhizoids of liverworts, are composed of rows of elongated cells and are branched. The leaves are simple, and except for the midrib are only one layer of cells thick. The structure of the stem though simple is more complicated than in any liverwort. The superficial cells are thick-walled, and there is a central strand of narrow cells forming a water-conducting tissue. The small strand of elongated cells in the midrib of the leaf runs down into the stem, but is not usually connected with the central strand. The sexual organs are developed in groups at the apices, the antheridial group usually terminating the main axis while the archegonia are borne on a lateral branch. The brown tint of the hair-like paraphyses mixed with antheridia (fig. 15) makes the male branch conspicuous, while the archegonia have to be carefully looked for enclosed by the surrounding leaves (fig. 16, B). The sporogonium developed from the fertilized ovum grows by means of a two-sided apical cell (fig. 16 A), and is at first of uniform thickness. After a time the upper region increases in diameter and forms the capsule, while the lower portion forms the long seta and the foot which is embedded in the end of the stem. With the growth of the sporogonium the archegonial wall, which for a time kept pace with it, is broken through, the larger upper part terminated by the neck being carried up on the capsule as the calyptra, while the basal portion remains as a tubular sheath round the lower end of the seta (cf. figs. 16, C, and fig. 11, A, B). The seta widens out at the base of the capsule into a region known as the apophysis. The peripheral cells of the seta are thick-walled, and it has a central strand of elongated conducting cells. In the epidermis of the apophysis functional stomata, similar to those of the higher plants, are present and, since cells containing chlorophyll are present below the superficial layers of the apophysis and capsule, the sporogonium is capable of independent assimilation. The construction of the capsule will be best understood from the median longitudinal section (fig. 11, C). The central region extending between the apophysis and the operculum is composed of sterile tissue and forms the columella (c). Immediately around this is the layer of cells from which the spores will be developed (s), and the layers of cells on either side of this form the walls of the spore-sac, which will contain the spores. Between the wall of the capsule, which is composed of several layers of cells, and the spore-sac is a wide intercellular space (h) bridged across by trabeculae consisting of rows of chlorophyll-containing cells. At the junction of the operculum (d) with the rest of the capsule is a circle of cells forming the annulus (a), by help of which the operculum is detached at maturity as a small lid. Its removal does not, however, leave the mouth of the capsule wide open, for around the margin are two circles of pointed teeth forming the peristome. These are the thickened cell-walls of a definite layer of cells (p), and appear [v.04 p.0651] as separate teeth owing to the breaking down of the unthickened cell-walls. The numerous spores which have been developed in the spore sac can thus only escape from the pendulous capsule through narrow slits between the teeth, and these are closed in damp air. The unicellular spores when supplied with moisture germinate (fig. 12) and give rise to the sexual generation. A filamentous protonema is first developed, some of the branches of which are exposed to the light and contain abundant chlorophyll, while others penetrate the substratum as brown or colourless rhizoids. The moss-plants arise from single projecting cells, and numerous plants may spring from the protonema developed from a single spore.

A, Germinating spores. s, Wall of spore; v, vacuole; w, rhizoid.

B, Part of a developed protonema. h, Creeping filament with brown walls from which the filaments of chlorophyll-containing cells (b) arise; k, young moss-plant; w, its first rhizoid.]

The majority of the mosses belong to the same great group as _Funaria_, the Bryales. The other two subdivisions of the Musci are each represented by a single genus. In the Andreaeales the columella does not extend to the upper end of the capsule, and the latter opens by a number of lateral slits. The Sphagnales also have a dome-shaped spore-sac continued over the columella, and, though their capsule opens by an operculum, they differ widely from other mosses in the development of the sporogonium as well as in the characters of the sexual generation. The three groups are described separately below, but some more general features of the mosses may be considered here.

On the whole mosses grow in drier situations than the liverworts, and the arrangements they present for the conduction of water in the plant are also more complete and suggest in some cases comparisons with the higher plants. In spite of this, however, they are in great part dependent on the absorption of water through the general surface of the shoot, and the power of rapid imbibition possessed by their cell-walls, the crowded position of the small leaves on the stem, and special adaptations for the retention of water on the surface, have the same significance as in the foliose liverworts. The different appearance of exposed mosses in dry weather and after a shower illustrates this relation to the water supply. The protonema is always a well-marked stage in the life-history. Not only does a moss-plant never arise directly from the spore, but in all cases of vegetative reproduction, apart from the separation of branches by decay of older regions of the plant, a protonema is found. Usually the protonema is filamentous and ceases to be evident after the plants have developed. But in some small mosses (e.g. _Ephemerum_) it plays the chief part in assimilation and lives on from year to year. In _Sphagnum_, _Andreaea_ and some genera of the Bryales the protonema or some of its branches have the form of flat plates or masses of cells. The formation of the moss-plant on the protonema is always from a single cell and is similar in all mosses. The first three walls in this cell intersect one another, and define the three-sided pyramidal apical cell by means of which the shoot continues to grow. In _Fissidens_ and a few other mosses the apical cell is two-sided. The leaves formed by the successive segments gradually attain their normal size and structure. Each segment of the initial cell gives rise to a leaf and a portion of the stem; the branches arise from the lower portion of a segment and stand immediately below a leaf. The leaves may form three vertical rows, but usually their arrangement, owing to the direction of the segment walls at the apex, becomes more complicated. Their growth proceeds by means of a two-sided apical cell, and the midrib does not become more than one cell thick until later. In addition to the leaves the stem often bears hair-like structures of different kinds, some of which correspond to modified branches of protonema. The branched filamentous rhizoids which spring from the lower region of the stem also correspond to protonemal branches. The structure of both stem and leaf reaches a high grade of organization in some mosses. Not only are thick-walled sclerenchymatous cells developed to give rigidity to the periphery of the stem and the midrib of the leaf, but in many cases a special water-conducting tissue, consisting of elongated cells, the end walls of which are thin and oblique, forms a definite central strand in the stem. In the forms in which it is most highly developed (Polytrichaceae) this tissue, which is comparable with the xylem of higher plants, is surrounded by a zone of tissue physiologically comparable to phloem, and in the rhizome may be limited by an endodermis. The conducting strands in the leaves show the same tissues as in the central strand of the stem, and in the Polytrichaceae and some other mosses are in continuity with it. The independent origin of this conducting system is of great interest for comparison with the vascular system of the sporophyte of the higher plants.

The sexual organs, with the exception of the antheridia of _Sphagnum_, are borne at the apices of the main shoot or of branches. Their general similarity to the mature antheridia and archegonia of liverworts and the main difference in their development have been referred to. The antheridia open by means of a cap cell or groups of cells with mucilaginous contents. The details of construction of the sporogonium are referred to below. In all cases (except _Archidium_) a columella is present, and all the cells derived from the archesporium produce spores, no elaters being formed. In a few cases the germination of the spore commences within the capsule. The development of the sporogonium proceeds in all cases (except in _Sphagnum_) by means of an apical cell cutting off two rows of segments. The first periclinal division in the region forming the capsule separates an inner group of cells (the endothecium) form the peripheral layer (amphithecium). In _Sphagnum_, as in _Anthoceros_, the archesporium is derived from the amphithecium; in all other mosses it is the outermost layer of the endothecium.

Vegetative propagation is widely spread in the mosses, and, as mentioned above, a protonema is always formed in the development of the new plant. The social growth of the plants characteristic of many mosses is a result of the formation of numerous plants on the original protonema and on developments from the rhizoids. Besides this, gemmae may be formed on the protonema, on the leaves or at the apex, and some mosses have specialized shoots for their better protection or distribution. Thus in _Georgia_ the stalked, multicellular gemmae are borne at the ends of shoots surrounded by a rosette of larger leaves, and in _Aulacomnium androgynum_ they are raised on an elongated leafless region of the shoot. In other cases detached leaves or shoots may give rise to new plants, and when a moss is artificially divided almost any fragment may serve for reproduction.

Even in those rare cases in which the sexual generation can be developed without the intervention of spore production from the tissues of the sporogonium, a protonema is formed from cut pieces of the seta or in some cases from intact sporogonia still attached to the plant. This phenomenon of _apospory_ was first discovered in mosses, but is now also known in a number of ferns (see PTERIDOPHYTA).

A. Longitudinal section of apex of a bud bearing archegonia (ar), enclosed by the large leaves (y); ch, small perichaetial leaves.

B. Longitudinal section of the sporogonium borne on the pseudopodium (ps); c, calyptra; ar, neck of archegonium; sg', foot; sg, capsule.

C. _S. squarrosum._ Ripe sporogonium raised on the pseudopodium (qs) above the enclosing leaves (ch); c, the ruptured calyptra; sg, capsule; d, operculum.]

_Sphagnales._--The single genus _Sphagnum_ occupies a very distinct and isolated position among mosses. The numerous species, which are familiar as the bog-mosses, are so similar that minute structural characters have to be relied on in their identification. The plants occur in large patches of a pale green or reddish colour on moors, and, when filling up small lakes or pools, may attain a length of some feet. Their growth has played a large part in the formation of peat. The species are distributed in temperate and arctic climates, but in the tropics only occur at high levels. The protonema forms a flat, lobed, thalloid structure attached to the soil by rhizoids, and the plants arise from marginal cells. The main shoot bears numerous branches which appear to stand in whorls; some of them bend down and become applied to the surface of the main axis. The structure of the stem and leaves is peculiar. The former shows on cross-section a thin-walled central tissue surrounded by a zone of thick-walled cells. Outside this come one to five layers of large clear cells, which when mature are dead and empty; their walls are strengthened with a spiral thickening and perforated with round pores. They serve to absorb and conduct water by capillarity. The leaves have no midrib and similar empty cells occur regularly among the narrow chlorophyll-containing cells, which thus appear as a green network. The antheridia are globular and have long stalks. They stand by the side of leaves of special club-shaped branches. The archegonial groups occupy the apices of short branches (fig. 13, A.). The mature sporogonium consists of a wide foot separated by a constriction from the globular capsule (B). There is no distinct seta, but the capsule is raised on a leafless outgrowth of the end of the branch called a pseudopodium (C, qs). The capsule, the wall of which bears rudimentary stomata, has a small operculum but no peristome. There is a short, wide columella, over which the dome-shaped spore-sac extends, and no air-space is present between the spore-sac and the wall. In the embryo a number of tiers of cells are first formed. The lower tiers [v.04 p.0652] form the foot, while in the upper part the first divisions mark off the columella, around which the archesporium, derived from the amphithecium, extends. The sporogonium when nearly mature bursts the calyptra irregularly. The capsule opens explosively in dry weather, the operculum and spores being thrown to a distance. The spore on germination forms a short filament which soon broadens out into the thalloid protonema. Some twelve species of _Sphagnum_ are found in Britain.

(k) ps, Pseudopodium.

c, Calyptra.

spf, Foot of sporogonium.

From Strasburger's _Textbook of Botany_]

_Andreaeales._--The species of the single genus _Andreaea_ (fig. 14) are small, dark-coloured mosses growing for the most part in tufts on bare rocks in alpine and arctic regions. Four species occur on alpine rocks in Britain. The spore on germination gives rise to a small mass of cells from which one or more short filaments grow. The filament soon broadens into a ribbon-shaped thallus, several cells thick, which is closely applied to the rock. Erect branches may arise from the protonema, and gemmae may be developed on it. The stem of the plant, which arises in the usual way, has no conducting strand and the leaves may or may not have midribs. The leaf grows by a dome-shaped instead of by the usual two-sided initial cell. The antheridia are long-stalked. The upper portion of the archegonial wall is carried up as a calyptra on the sporogonium, which, as in _Sphagnum_, has no seta and is raised on a pseudopodium. The development of the sporogonium proceeds as in the Bryales, but the dome-shaped archesporium extends over the summit of the columella and an air-space is wanting. The capsule does not open by an operculum but by four or six longitudinal slits, which do not reach either the base or apex. In one exotic species the splits occur only at the upper part of the capsule, and the terminal cap breaks away. This isolated example thus appears to approach the Bryales in its mode of dehiscence.

_Bryales._--In contrast to the preceding two this group includes a very large number of genera and species. Thus even in Britain between five and six hundred species belonging to more than one hundred genera are found. They occur in the most varied situations, on soil, on rocks and trees, and, in a few instances (_Fontinalis_), in water. Although exhibiting a wide range in size and in the structural complexity of both generations, they all conform to a general type, so that _Funaria_, described above, will serve as a fair example of the group. The protonema is usually filamentous, and in some of the simplest forms is long-lived, while the small plants borne on it serve mainly to protect the sexual organs and sporogonia. This is the case in _Ephemerum_, which grows on the damp soil of clayey fields, and the plants are even more simply constructed in _Buxbaumia_, which occurs on soil rich in humus and is possibly partially saprophytic. In this moss the filamentous protonema is capable of assimilation, but the leaves of the small plants are destitute of chlorophyll, so that they are dependent on the protonema. The male plant has no definite stem, and consists of a single concave leaf protecting the antheridium. The female plant is rather more highly organized, consisting of a short stem bearing a few leaves around the group of archegonia. The sporogonium is of large size and highly organized, though it presents peculiar features in the peristome. _Buxbaumia_ has been regarded by Goebel as representing a stage which other mosses have passed, and has been described by him as the simplest type of moss. In _Ephemerum_ also we may probably regard the relation of the small plants to the protonema as a primitive one. On the other hand, in the case of _Ephemeropsis_, which grows on the leaves of living plants in Java, the high organization of the sporogonium makes it probable that the persistent protonema is an adaptation to the peculiar conditions of life. A highly developed protonema provided with leaf-like assimilating organs is found in _Georgia_, _Diphyscium_ and _Oedipodium_, all of which show peculiarities in the sporogonium as well. The cells of the protonema of _Schistostega_, which lives in the shade of caves, are so constructed as to concentrate the feeble available light on the chloroplasts.

We may perhaps regard the persistent protonema bearing small leafy plants as a primitive condition, and look upon those larger plants which remain unbranched and bear the sexual organs at the apex (e.g. _Schistostega_) as representing the next stage. From this condition different lines of specialization in the form and structure of the plant can be recognized. A large number of mosses stand at about the same grade as _Funaria_, in that the plants are small, sparingly branched, usually radial, and do not show a very highly differentiated internal structure. In others the form of the plant becomes more complex by copious branching and the differentiation of shoots of different orders. In these cases the shoot system is often more or less dorsiventral, and the sexual organs are borne on short lateral branches (e.g. _Thuidium tamariscinum_). The Polytrichaceae, on the other hand, show a specialization in structure rather than in form. The high organization of their conducting system has been referred to above, but though many species are able to exist in relatively dry situations, the plants are still dependent on the absorption of water by the general surface. The parallel lamellae of assimilating cells which grow from the upper surface of the leaf in these and some other mosses probably serve to retain water in the neighbourhood of the assimilating cells and so prolong their activity. As common adaptive features in the leaves the occurrence of papillae or outgrowths of the cell-walls to retain water, and the white hairlike leaf tips, which assist in protecting the young parts at the apex of many xerophytic mosses, may be mentioned. The leaves of _Leucobryum_, which occurs in pale green tufts in shaded woods, show a parallel adaptation to that found in _Sphagnum_. They are several cells thick, and the small assimilating cells lie between two layers of empty water-storage cells, the walls of which are perforated by pores.

With the possible exception of _Archidium_, the sporogonium is throughout the Bryales constructed on one plan. _Archidium_ is a small moss occurring occasionally on the soil of wet fields. The protonema is not persistent, and the plants are well developed, resembling those of _Pleuridium_. The sporogonium has a small foot and practically no seta, and differs in the development and structure of its capsule from all other mosses. The spores are derived from the endothecium, but no distinction of a sterile columella and an archesporium is established in this, a variable number of its cells becoming spore-mother-cells while the rest serve to nourish the spores. The layer of cells immediately around the endothecium becomes the spore-sac, and an air-space forms between this and the wall of the capsule. The very large, thin-walled spores escape on the decay of the capsule, which ruptures the archegonial wall irregularly. On account of the absence of a columella _Archidium_ is sometimes placed in a distinct group, but since its peculiarities have possibly arisen by reduction it seems at present best retained among the Bryales. In all other Bryales there is a definite columella extending from the base to the apex of the capsule, the archesporium is derived from the outermost layer of cells of the endothecium, and an air space is formed between the spore-sac and the wall. In the Polytrichaceae another air space separates the spore-sac from the columella. There is great variety in the length of the seta, which is sometimes practically absent. The apophysis, which may be a more or less distinct region, usually bears stomata and is the main organ of assimilation. In the Splachnaceae it is expanded for this purpose, while in _Oedipodium_ it constitutes most of the long pale stalk which supports the capsule. A distinct operculum is usually detached by the help of the annulus, and its removal may leave the mouth of the capsule widely open. More usually there is a peristome, consisting of one or two series of teeth, which serves to narrow the opening and in various ways to ensure the gradual shedding of the spores in dry weather. In most mosses the teeth are portions of thickened cell-walls but in the Polytrichaceae they are formed of a number of sclerenchymatous cells. In _Polytrichum_ a membranous epiphragm stretches across the wide mouth of the capsule between the tips of the short peristome teeth, and closes the opening except for the interspaces of the peristome.

In a number of forms, which were formerly grouped together, the capsule does not open to liberate the spores. These cleistocarpous forms are now recognized as related to various natural groups, in which the majority of the species possess an operculum. In such forms as _Phascum_ the columella persists, and the only peculiarity is in the absence of arrangements for dehiscence. In _Ephemerum_ [v.04 p.0653] (and the closely related _Nanomitrium_ which has a small operculum) the columella becomes absorbed during the development of the spores. Stomata are present on the wall of the small capsule. Such facts as these suggest that in many cases the cleistocarpous condition is the result of reduction rather than primitive, and that possibly the same holds for _Archidium_.

The former subdivision of the Bryales into Musci Cleistocarpi and Musci Stegocarpi according to the absence or presence of an operculum is thus clearly artificial. The same holds even more obviously for the grouping of the stegocarpous forms into those in which the archegonial group terminates a main axis (acrocarpi) and those in which it is borne on a more or less developed lateral branch (pleurocarpi). Modern classifications of the Bryales depend mainly on the construction of the peristome.

e, Leaves.

d, Leaves cut through the mid-ribs.

c, Paraphyses.

b, Antheridia.]

It remains to be considered to what extent the several natural groups of plants classed together in the Bryophyta can be placed in a phylogenetic relation to one another. Practically no help is afforded by palaeobotany, and only the comparison of existing forms can be depended on. The indications of probable lines of evolution are clearest in the Hepaticae. The Marchantiales form an obviously natural evolutionary group, and the same is probably true of the Jungermanniales, although in neither case can the partial lines of progression within the main groups be said to be quite clear. Such a form as _Sphaerocarpus_, which has features in common with the lower Marchantiales, enables us to form an idea of the divergence of the two groups from a common ancestry. The Anthocerotales, on the other hand, stand in an isolated position, and recent researches have served to emphasize this rather than to confirm the relationship with the Jungermanniales suggested by Leitgeb. The indications of a serial progression are not so clear in the mosses, but the majority of the forms may be regarded as forming a great phylogenetic group in the evolution of which the elaboration of the moss-plant has proceeded until the protonema appears as a mere preliminary stage to the formation of the plants. Parallel with the evolution of the gametophyte in form and structure, a progression can be traced in the sporogonium, although the simplest sporogonia available for study may owe much of their simplicity to reduction. The Andreaeales may perhaps be looked on as a divergent primitive branch of the same stock. On the other hand, the Sphagnales show such considerable and important differences from the rest of the mosses, that like the Anthocerotales among the liverworts, they may be regarded as a group, the relationship of which to the main stem is at least problematical. Between the Hepaticae, Anthocerotales, Sphagnales and Musci, there are no connecting forms known, and it must be left as an open question whether the Bryophyta are a monophyletic or polyphyletic group.

The question of the relationship of the Bryophyta on the one hand to the Thallophyta and on the other to the Pteridophyta lies even more in the region of speculation, on slender grounds without much hope of decisive evidence. In a general sense we may regard the Bryophyta as derived from an algal ancestry, without being able to suggest the nature of the ancestral forms or the geological period at which they arose. Recent researches on those Algae such as _Coleochaete_ which appeared to afford a close comparison in their alternation of generations with _Riccia_, have shown that the body resulting from the segmentation of the fertilized ovum is not so strictly comparable in the two cases as had been supposed. The series of increasingly complex sporogonia among Bryophytes appears to be most naturally explained on an hypothesis of progressive sterilization of sporogenous tissue, such as has been advanced by Bower. On the other hand there are not wanting indications of reduction in the Bryophyte sporogonium which make an alternative view of its origin at least possible. With regard to the relationship of the Bryophyta and Pteridophyta the article on the latter group should be consulted. It will be sufficient to say in conclusion that while the alternating generations in the two groups are strictly comparable, no evidence of actual relationship is yet forthcoming.

A. Longitudinal section of the very young sporogonium (f, f') enclosed in the archegonial wall (b, h).

B, C. Further stages of the development of the sporogonium (f) enclosed in the calyptra formed from the archegonial wall (c) and still bearing the neck (h). The foot of the sporogonium has penetrated into the underlying tissue of the stem of the moss-plant.]

For further information consult: Campbell, _Mosses and Ferns_ (London, 1906); Engler and Prantl, _Die naturlichen Pflanzenfamilien_, Teil i. Abt. 3 (Leipzig, 1893-1907); Goebel, _Organography of Plants_ (Oxford, 1905). Full references to the literature of the subject will be found in these works. For the identification of the British species of liverworts and mosses the following recent works will be of use: Pearson, _The Hepaticae of the British Isles_ (London, 1902); Dixon and Jameson, _The Student's Handbook of British Mosses_ (London, 1896); Braithwaite, _British Moss Flora_ (London, 1887-1905).

(W. H. L.)

BRZOZOWSKI, THADDEUS (d. 1820), nineteenth general of the Jesuits, was appointed in succession to Gabriel Gruber on the 2nd of September 1805. In 1801 Pius VII. had given the Jesuits liberty to reconstitute themselves in north Russia (see JESUITS: _History_), and in 1812 Brzozowski secured the recognition of the Jesuit college of Polotsk as a university, though he could not obtain permission to go to Spain to agitate for the recognition [v.04 p.0654] of the Spanish Jesuits. In 1814 Pius VII., in accordance with the bull _Sollicitudo omnium ecclesiarum_, gave to Brzozowski among others full authority to receive those who desired to enter the society. The Russian government, however, soon began to be alarmed at the growth of the Jesuits, and on the 20th of December 1815 published an edict expelling them from St Petersburg. Brzozowski, having vainly requested to be allowed to retire to Rome, died on the 5th of February 1820. He is interesting mainly from the fact that he was general of the Society at the time of its restoration throughout Europe.

BUBASTIS, the Graecized name of the Egyptian goddess Ubasti, meaning "she of [the city] Bast" (B;s-t), a city better known by its later name, P-ubasti, "place of Ubasti"; thus the goddess derived her name Ubasti from her city (Bast), and in turn the city derived its name P-ubasti from that of the goddess; the Greeks, confusing the name of the city with that of the goddess, called the latter Bubastis, and the former also Bubastis (later Bubastos). Bubastis, capital of the 19th nome of Lower Egypt, is now represented by a great mound of ruins called Tell Basta, near Zagazig, including the site of a large temple (described by Herodotus) strewn with blocks of granite. The monuments discovered there, although only those in hard stone have survived, are more important than at any other site in the Delta except Tanis and cover a wider range, commencing with Khufu (Cheops) and continuing to the thirtieth dynasty.

Ubasti was one of many feline goddesses, figured with the head of a lioness. In the great development of reverence for sacred animals which took place after the New Kingdom, the domestic cat was especially the animal of Bubastis, although it had also to serve for all the other feline goddesses, owing no doubt to the scarcity and intractability of its congeners. Her hieratic and most general form was still lioness-headed, but a popular form, especially in bronze, was a cat-headed women, often holding in her right hand a lion aegis, i.e. a broad semicircular pectoral surmounted by the head of a lioness, and on the left arm a basket. The cat cemetery on the west side of the town consisted of numbers of large brick chambers, crammed with burnt and decayed mummies, many of which had been enclosed in cat-shaped cases of wood and bronze. Herodotus describes the festival of Bubastis, which was attended by thousands from all parts of Egypt and was a very riotous affair; it has its modern equivalent in the Moslem festival of the sheikh Said el Badawi at Tanta. The tablet of Canopus shows that there were two festivals of Bubastis, the great and the lesser: perhaps the lesser festival was held at Memphis, where the quarter called Ankhto contained a temple to this goddess. Her name is found on monuments from the third dynasty onwards, but a great stimulus was given to her worship by the twenty-second (Bubastite) dynasty and generally by the increased importance of Lower Egypt in later times. Her character seems to have been essentially mild and playful, in contrast to Sokhmi and other feline goddesses. The Greeks equated Ubasti with their Artemis, confusing her with the leonine Tafne, sister of Shöou (Apollo). The Egyptians themselves delighted in identifying together goddesses of the most diverse forms and attributes; but Ubasti was almost indistinguishable in form from Tafne. The name of her son Iphthimis (Nfr-tm), pronounced Eftem, may mean "All-good," and, in the absence of other information about him, suggests a reason why he was identified with Prometheus.

See K. Sethe in Pauly-Wissowa's _Realencyclopädie_; E. Naville, _Bubastis_, and _Festival Hall of Osorkon II._; Herodotus ii. 67, 137-156; Grenfell and Hunt, _Hibeh Papyri_, i.

(F. LL. G.)

BUCARAMANGA, a city of Colombia, capital of the department of Santandér, about 185 m. N.N.E. of Bogotá. Pop. (estimate, 1902) 25,000. It is situated on the Lebrija river, 3248 ft. above sea-level, in a mountainous country rich in gold, silver and iron mines, and having superior coffee-producing lands in the valleys and on the lower slopes. The city is laid out with wide, straight streets, is well built, and has many public buildings of a substantial character.

BUCCANEERS, the name given to piratical adventurers of different nationalities united in their opposition to Spain, who maintained themselves chiefly in the Caribbean Sea during the 17th century.

The island of Santo Domingo was one of several in the West Indies which had early in the 16th century been almost depopulated by the oppressive colonial policy of Spain. Along its coast there were several isolated establishments presided over by Spaniards, who were deprived of a convenient market for the produce of the soil by the monopolies imposed by the mother country. Accordingly English, Dutch and French vessels were welcomed and their cargoes readily bought. The island, thinned of its former inhabitants, had become the home of immense herds of wild cattle; and it became the habit of smugglers to provision at Santo Domingo. The natives still left were skilled in preserving flesh at their little establishments called _boucans_. The adventurers learned "boucanning" from the natives; and gradually Hispaniola became the scene of an extensive and illicit butcher trade. Spanish monopolies filled the seamen who sailed the Caribbean with a natural hate of everything Spanish. The pleasures of a roving life, enlivened by occasional skirmishes with forces organized and led by Spanish officials, gained upon them. Out of such conditions arose the buccaneer, alternately sailor and hunter, even occasionally a planter--roving, bold, unscrupulous, often savage, with an intense detestation of Spain. As the Spaniards would not recognize the right of other races to make settlements, or even to trade in the West Indies, the governments of France, England and Holland would do nothing to control their subjects who invaded the islands. They left them free to make settlements at their own risk. Each nation contributed a band of colonists, who selected the island of St Kitts or St Christopher, in the West Indies, where the settlers of both nations were simultaneously planted. The English and French were, however, not very friendly; and in 1629, after the retirement of several of the former to an adjoining island, the remaining colonists were surprised and partly dispersed by the arrival of a Spanish fleet of thirty-nine sail. But on the departure of the fleet the scattered bands returned, and encouragement was given to their countrymen in Santo Domingo. For buccaneering had now become a most profitable employment, operations were extended, and a storehouse secure from the attacks of the Spaniards was required. The small island of Tortuga (north-west of Hispaniola) was seized for this purpose in 1630, converted into a magazine for the goods of the rivals, and made their headquarters, Santo Domingo itself still continuing their hunting ground. A purely English settlement directed by a company in London was made at Old Providence, an island in the Caribbean Sea, now belonging to Colombia. It began a little before 1630, and was suppressed by the Spaniards in 1641.

Spain was unable to take immediate action. Eight years later, however, watching their opportunity when many buccaneers were absent in the larger island, the Spaniards attacked Tortuga, and massacred every settler they could seize. But the others returned; and the buccaneers, now in open hostility to the Spanish arms, began to receive recruits from every European trading nation, and for three-quarters of a century became the scourge of the Spanish-American trade and dominions.

France, throughout all this, had not been idle. She had named the governor of St Kitts "Governor-General for the French West India Islands," and in 1641 he took possession of Tortuga, expelled all English from the island, and attempted the same with less success in Santo Domingo. England was absorbed in the Civil War, and the buccaneers had to maintain themselves as best they could,--now mainly on the sea.

In 1654 the Spaniards regained Tortuga from the French, into whose hands it again, however, fell after six years. But this state of affairs was too insecure even for these rovers, and they would speedily have succumbed had not a refuge been found for them by the fortunate conquest of Jamaica in 1655 by the navy of the English Commonwealth. These conquests were not made without the aid of the buccaneers themselves. The taking and re-taking of Tortuga by the French was always with the assistance of the roving community; and at the conquest of Jamaica the English navy had the same influence in its favour. The [v.04 p.0655] buccaneers, in fact, constituted a mercenary navy, ready for employment against the power of Spain by any other nation, on condition of sharing the plunder; and they were noted for their daring, their cruelty and their extraordinary skill in seamanship.

Their history now divides itself into three epochs. The first of these extends from the period of their rise to the capture of Panama by Morgan in 1671, during which time they were hampered neither by government aid nor, till near its close, by government restriction. The second, from 1671 to the time of their greatest power, 1685, when the scene of their operations was no longer merely the Caribbean, but principally the whole range of the Pacific from California to Chile. The third and last period extends from that year onwards; it was a time of disunion and disintegration, when the independence and rude honour of the previous periods had degenerated into unmitigated vice and brutality.

It is chiefly during the first period that those leaders flourished whose names and doings have been associated with all that was really influential in the exploits of the buccaneers--the most prominent being Mansfield and Morgan. The floating commerce of Spain had by the middle of the 17th century become utterly insignificant. But Spanish settlements remained; and in 1654 the first great expedition on land made by the buccaneers, though attended by considerable difficulties, was completed by the capture and sack of New Segovia, on the mainland of America. The Gulf of Venezuela, with its towns of Maracaibo and Gibraltar, were attacked and plundered under the command of a Frenchman named L'Ollonois, who performed, it is said, the office of executioner upon the whole crew of a Spanish vessel manned with ninety seamen. Such successes removed the buccaneers further and further from the pale of civilized society, fed their revenge, and inspired them with an avarice almost equal to that of the original settlers from Spain. Mansfield indeed, in 1664, conceived the idea of a permanent settlement upon a small island of the Bahamas, named New Providence, and Henry Morgan, a Welshman, intrepid and unscrupulous, joined him. But the untimely death of Mansfield nipped in the bud the only rational scheme of settlement which seems at any time to have animated this wild community; and Morgan, now elected commander, swept the whole Caribbean, and from his headquarters in Jamaica led triumphant expeditions to Cuba and the mainland. He was leader of the expedition wherein Porto Bello, one of the best-fortified ports in the West Indies, was surprised and plundered.

This was too much for even the adverse European powers; and in 1670 a treaty was concluded between England and Spain, proclaiming peace and friendship among the subjects of the two sovereigns in the New World, formally renouncing hostilities of every kind. Great Britain was to hold all her possessions in the New World as her own property (a remarkable concession on the part of Spain), and consented, on behalf of her subjects, to forbear trading with any Spanish port without licence obtained.

The treaty was very ill observed in Jamaica, where the governor, Thomas Modyford (1620-1679), was in close alliance with the "privateers," which was the official title of the buccaneers. He had already granted commissions to Morgan and others for a great attack on the Isthmus of Panama, the route by which the bullion of the South American mines was carried to Porto Bello, to be shipped to Spain. The buccaneers to the number of 2000 began by seizing Chagres, and then marched to Panama in 1671. After a difficult journey on foot and in canoes, they found themselves nearing the shores of the South Sea and in view of the city. On the morning of the tenth day they commenced an engagement which ended in the rout of the defenders of the town. It was taken, and, accidentally or not, it was burnt. The sack of Panama was accompanied by great barbarities. The Spaniards had, however, removed the treasure before the city was taken. When the booty was divided, Morgan is accused of having defrauded his followers. It is certain that the share per man was small, and that many of the buccaneers died of starvation while trying to return to Jamaica. Modyford was recalled, and in 1672 Morgan was called home and imprisoned in the Tower. In 1674 he was allowed to come back to the island as lieutenant-governor with Lord Vaughan. He had become so unpopular after the expedition of 1671 that he was followed in the streets and threatened by the relations of those who had perished. During his later years he was active in suppressing the buccaneers who had now inconvenient claims on him.

From 1671 to 1685 is the time of the greatest daring, prosperity and power of the buccaneers. The expedition against Panama had not been without its influence. Notwithstanding their many successes in the Caribbean and on land, including a second plunder of Porto Bello, their thoughts ran frequently on the great expedition across the isthmus, and they pictured the South Sea as a far wider and more lucrative field for the display of their united power.

In 1680 a body of marauders over 300 strong, well armed and provisioned, landed on the shore of Darien and struck across the country; and the cruelty and mismanagement displayed in the policy of the Spaniards towards the Indians were now revenged by the assistance which the natives eagerly rendered to the adventurers. They acted as guides during a difficult journey of nine days, kept the invaders well supplied with food, provided them with canoes, and only left them after the taking of the fort of Santa Maria, when the buccaneers were fairly embarked on a broad and safe river which emptied itself into the South Sea. With John Coxon as commander they entered the Bay of Panama, where rumour had been before them, and where the Spaniards had hastily prepared a small fleet to meet them. But the valour of the buccaneers won for them another victory; within a week they took possession of four Spanish ships, and now successes flowed upon them. The Pacific, hitherto free from their intrusion, showed many sail of merchant vessels, while on land opposition south of the Bay of Panama was of little avail, since few were acquainted with the use of fire-arms. Coxon and seventy men returned as they had gone, but the others, under Sawkins, Sharp and Watling, roamed north and south on islands and mainland, and remained for long ravaging the coast of Peru. Never short of silver and gold, but often in want of the necessaries of life, they continued their practices for a little longer; then, evading the risk of recrossing the isthmus, they boldly cleared Cape Horn, and arrived in the Indies. Again, in 1683, numbers of them under John Cook departed for the South Sea by way of Cape Horn. On Cook's death his successor, Edward Davis, undoubtedly the greatest and most prudent commander who ever led the forces of the buccaneers at sea, met with a certain Captain Swan from England, and the two captains began a cruise which was disastrous to the Spanish trade in the Pacific.

In 1685 they were joined in the Bay of Panama by large numbers of buccaneers who had crossed the isthmus under Townley and others. This increased body of men required an enlarged measure of adventure, and this in a few months was supplied by the viceroy of Peru. That officer, seeing the trade of the colony cut off, supplies stopped, towns burned and raided, and property harassed by continual raids, resolved by vigorous means to put an end to it. But his aim was not easily accomplished. In this same year a Spanish fleet of fourteen sail met, but did not engage, ten buccaneer vessels which were found in the Bay of Panama.

At this period the power of the buccaneers was at its height. But the combination was too extensive for its work, and the different nationality of those who composed it was a source of growing discord. Nor was the dream of equality ever realized for any length of time. The immense spoil obtained on the capture of wealthy cities was indeed divided equally. But in the gambling and debauchery which followed, nothing was more common than that one-half of the conquerors should find themselves on the morrow in most pressing want; and while those who had retained or increased their share would willingly have gone home, the others clamoured for renewed attacks. The separation of the English and French buccaneers, who together presented a united front to the Spanish fleet in 1685, marks the beginning of the third and last epoch in their history.