Chapter III: TRICHIA, Haller. Sporangia regular and stipitate or sessile and

somewhat irregular; the wall, at maturity, irregularly ruptured. The stipe more or less elongated or often wanting, usually resting on a hypothallus. Capillitium consisting of numerous short slender tubules, called _elaters_, intermingled with the spores and wholly free; elaters simple or rarely branched a time or two, each extremity terminating in a smooth tapering point; the spiral ridges parallel and conspicuous, 2-5 in number, smooth or spinulose. Spores globose, yellow, ochraceous, olivaceous.

The genus Trichia is unique among the Myxomycetes in having its capillitium composed of tubules, which are entirely free from the wall of the sporangium. The length of these free tubes varies usually between .3 mm. and .5 mm., being sometimes shorter, but seldom longer; they are typically cylindric, or equally thickened from end to end, or quite rarely they are thickened in the middle, and taper gradually to each extremity; the extremities terminate in a smooth tapering point, straight or sometimes a little curved or flexuous, which maintains an average length in each species. The spiral ridges wind around the thread almost invariably to the left, or with the hands of a watch; they are always more or less prominent and conspicuous, and usually maintain a regular curve and uniform interval between each other in the same species; their surface is either smooth, or sometimes it is invested with minute warts or spinules.

In all the species of this genus, however, irregular and abnormal elaters are occasionally met with among the typical ones. As these abnormal forms always arrest attention, and have been conceived to possess specific value, it may be well to note the principal of them.

1. The elater is sometimes branched. In two or three species the branching appears to be quite regular and not abnormal; still, even in these species, most of the elaters in the sporangia are not branched. In some cases the branching arises from confluence of two or more elaters.

2. Ellipsoidal swellings, or enlargements of the elater, sometimes occur, at one or both extremities, or at points intermediate between them; these always occur irregularly, and are essentially abnormal.

3. The smooth tapering point is rarely wanting, in which case the extremity presents a blunt end, the spiral ridges running to the end. More frequently the tapering points are multiplied, the elaters bearing two or three spines at the extremities; this often occurs in the species of Trichia, and also of Hemiarcyria with spinulose elaters.

4. The spiral ridges are sometimes defective, there being less than the typical number; sometimes they are merely displaced, there being a much wider interval between them than usual; rarely do they habitually wind about the thread in an irregular manner.

5. Under high magnifying power, fine ridges are sometimes seen running lengthwise of the elaters, bridging the intervals between the spirals. These were first observed by DeBary, in _Trichia chrysosperma_, but they have since been seen in the elaters of nearly every other species of Trichia, and also in species of Hemiarcyria.

The few species with elaters, so far as yet known, habitually irregular, defective and abnormal, are referred to the genus Oligonema.

The normal species of Trichia arrange themselves quite naturally into three sections.

§1. A NACTIUM. Sporangia varying from globose to pyriform or turbinate, supported on a more or less elongated stipe. Spores globose, the surface minutely warted.

_a. Elaters with very long tapering extremities._

1. TRICHIA FRAGILIS, Sow. Sporangia obovoid to pyriform or clavate, often fasciculate, stipitate; the wall a thin membrane, with a thick dense outer layer of brown-red granules. Stipes long, erect or curved, simple or usually fasciculate and often connate, arising from a thin hypothallus. Mass of spores and capillitium from reddish-brown to yellow and ochraceous; elaters simple, rarely branched, 4-5 mic. thick, with very long tapering extremities, ending in smooth points 8-12 mic. long; spirals, three or four, perfectly smooth. Spores globose, minutely warted, 10-12 mic. in diameter.

Growing on old wood. Sporangia with the stipe 2-4 mm. in height, the sporangium .6-.8 mm. in diameter, the stipe usually longer than the sporangium. The color quite variable, mostly dull red-brown or blackish-brown, more rarely yellow or coffee-brown, usually opaque, rarely shining.

2. TRICHIA FALLAX, Pers. Sporangium obovoid to pyriform or turbinate, rarely clavate, stipitate; the wall thin, smooth and shining, colored as the spores and capillitium. Stipe more or less elongated, simple, erect, brownish below, filled with roundish vesicles. Mass of capillitium and spores yellowish, ochraceous or olivaceous; elaters simple or sometimes with several branches, 4-6 mic. thick in the middle, tapering gradually to each extremity, ending in smooth tapering points, 20-40 mic. in length; spirals, three, perfectly smooth. Spores globose, minutely warted, 10-12 mic. in diameter. See Plate I, Fig. 22.

Growing on old wood. Sporangium with the stipe 2-4 mm. in height, sporangium .6-.8 mm. in diameter, the stipe usually longer than the sporangium. Under high magnifying power the spores are seen to be minutely reticulated.

_b. Elaters cylindric, ending in a smooth tapering point._

3. TRICHIA SUBFUSCA, Rex. Sporangium globose, rarely globose-turbinate, stipitate; the wall thickish, dull tawny-brown above, shading to dark brown at the base. Stipe simple, erect, brown or blackish in color. Mass of capillitium and spores bright yellow; elaters simple, rarely branched, cylindric, 3.5-4 mic. in thickness, ending in smooth tapering points, 10-12 mic. in length; spirals, four in number, perfectly smooth. Spores globose, minutely warted, 11.5-12.5 mic. in diameter.

On old wood and bark, Adirondack Mountains, New York. Dr. George A. Rex. Sporangium .5-.8 mm. in diameter, the stipe equal in height to the diameter of the sporangium.

4. TRICHIA ERECTA, Rex. Sporangium globose to globose-turbinate, stipitate; the wall of both sporangium and stipe with a rough outer layer of brown scales and granules, which, on the upper surface of the sporangium, soon breaks up into irregular patches. Stipes long, erect, usually simple, rarely fasciculate and connate. Mass of capillitium and spores, bright yellow; elaters simple, cylindric, 4 mic. in thickness, ending in smooth points, 4-6 mic. long; spirals four, often united by intervening branches, covered with numerous irregular spinules. Spores globose, minutely warted, 12-14 mic. in diameter.

Growing on old wood and bark, Adirondack Mountains, New York, Dr. Geo. A. Rex. Sporangium .5-.8 mm. in diameter, the stipe about 1 mm. in height. This Trichia is conspicuous by the checkering or areolation of the upper surface in the mature sporangia, affording a sharp contrast between the brown patches and the yellow bands.

§2. CHRYSOPHIDIA. Sporangia globose, obovoid or somewhat irregular, sessile, rarely with a short stipe, usually closely crowded. Spores globose, the surface minutely warted.

_a. Elaters perfectly smooth._

5. TRICHIA VARIA, Pers. Sporangia globose, obovoid or somewhat irregular, gregarious and scattered or crowded, yellowish, ochraceous or olivaceous, sessile, or with a very short brown or blackish stipe. Mass of capillitium and spores yellow; elaters long, simple or sometimes branched a time or two, 4-5 mic. in thickness, ending in a smooth tapering point, 8-12 mic. long; spirals only two, smooth, very prominent in places, causing the elater to appear notched. Spores globose, oval or somewhat irregular, minutely warted, 10-14 mic. in diameter.

Growing in patches on old wood; a very common species. Sporangium .6-.8 mm. in diameter, or when irregular sometimes elongated to 1 mm. or more. Extremely variable as to the form of the sporangium, but readily recognized by its elaters.

6. TRICHIA ANDERSONI, Rex. Sporangia globose or obovoid, sessile, gregarious, closely crowded, or sometimes scattered, the wall thickened with minute scales, in color brownish-ochre or olivaceous. Mass of capillitium and spores yellow; elaters long, simple, 3-4 mic. in thickness, ending in a very long flexuous point, 14-18 mic. in length; spirals three or four, winding evenly and closely, perfectly smooth. Spores globose, minutely warted, 10-12 mic. in diameter.

Growing on the inside of bark of Acer. Sporangium .4-.5 mm. in diameter. The capillitium is deep orange and the spores olivaceous, but this difference in shade of color between spores and capillitium occurs in other species. _Trichia advenula_, Mass., is a closely related species, the swellings in the elaters having no specific value.

7. TRICHIA INCONSPICUA, Rost. Sporangia very small, subglobose, sessile, collected together in clusters, or scattered, without any hypothallus; the wall brown, smooth and shining. Mass of capillitium and spores yellow; elaters long, simple, cylindric, 3-4 mic. in thickness, ending in smooth tapering points, 6-7 mic. in length; spirals three or four, close, not prominent, perfectly smooth. Spores globose, minutely warted, 10-12 mic. in diameter.

Growing on bark of Platanus, etc. New York, _Peck_; Iowa, _McBride_. The sporangia spherical or reniform and very small.

_b. Elaters spinulose._

8. TRICHIA IOWENSIS, McBride. Sporangia subglobose, sessile, gregarious, scattered, or sometimes close and confluent; the wall thickened with minute scales, reddish-brown in color. Mass of capillitium and spores yellow; elaters quite variable, usually very long, but sometimes very short, simple, rarely branched, the thickness unequal, 3-4 mic. in the same elater, with occasional thicker swellings, bearing numerous scattered spines, usually about as long as the thickness of the elater, but sometimes much longer, those at the ends being similar; spirals three or four, fine and close, in places nearly obsolete. Spores globose, or more or less irregular, minutely warted, 9-11 mic. in diameter.

Growing on old bark of Populus; Iowa, McBride. Sporangia .4-.5 mm. in diameter. This is a very curious species of Trichia; it suggests _Ophiotheca Wrightii_, but the elaters are short and simple, and there is no question as to the spirals upon them. I could find no branched elaters in my specimen.

9. TRICHIA SCABRA, Rost. Sporangia globose or somewhat irregular, sessile and closely crowded on a well-developed hypothallus; the wall thin, gold-yellow or orange to yellow-brown in color, smooth and shining. Mass of capillitium and spores orange or golden-yellow; elaters long, simple, 4-5 mic. in thickness, ending in a smooth tapering point, 5-8 mic. in length; spirals three or four, covered with numerous short acute spinules. Spores globose, minutely warted, 9-11 mic. in diameter. See Plate I, Fig. 23.

Growing on old wood in patches, sometimes several centimeters in extent. Sporangia .6-1 mm. in diameter. "The papillæ, which cover the spore, show, when highly magnified, a distinct net-like pattern," _McBride_. The elaters of this species are subject to much irregularity in the way of abnormal swellings, duplicating the spines at the apex, etc.; the spinules are sometimes quite obsolete on some or all of the elaters of a sporangium.

§3. GONIOSPORA, Fr. Sporangia obovoid to oblong, sessile and closely crowded on a well-developed common hypothallus. Spores with thick ridges upon the surface, which are combined into a more or less incomplete network of polygonal meshes.

The ridges of the epispore are 1-2 mic. in height, and do not present to the view more than two or three perfect polygons on a hemisphere of the spores; more often the reticulation is imperfect, the ridges being interrupted and defective. When highly magnified these ridges are seen to be "perforated through their thickness with one, two or three rows, or with clusters of cylindrical openings or pits, or are sculptured into intricate plexuses of minute reticulations with quadrilateral interspaces."

10. TRICHIA AFFINIS, DeB. Sporangia obovoid to oblong, sessile and closely crowded on a common hypothallus; the wall thin, golden-yellow to tawny or brownish-yellow, smooth and shining. Mass of capillitium and spores golden to tawny-yellow; elaters long, simple, 4-5 mic. in thickness, ending in a smooth tapering point, 6-10 mic. in length; spirals four, usually spinulose, rarely smooth. Spores angularly or irregularly globose, 10-12 mic. in diameter.

Growing on old wood and bark in small patches of a few millimeters to a centimeter or more in extent. Sporangia .6-.8 mm. in height by .4-.5 mm. in diameter. _Trichia Jackii_, Rost., is included in this species.

11. TRICHIA CHRYSOSPERMA, Bull. Sporangia oblong-obovoid to cylindric, sessile and closely crowded on a well-developed hypothallus; the wall thin, pale citron to olive-yellow, smooth and shining. Mass of capillitium and spores, golden to ochre-yellow; elaters long, simple, 6-8 mic. in thickness, ending in a smooth tapering point, 3-7 mic. in length; spirals four or five, usually smooth, rarely spinulose. Spores angularly or irregularly globose, 12-14 mic. in diameter.

Growing on old wood, in small patches, one to several centimeters in extent. Sporangia 1-2 mm. in height and .5-.6 mm. in diameter. This is readily distinguished from _Trichia affinis_ by the larger and differently colored sporangia.