--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. Ma.s.s 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. Ma.s.s 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. Ma.s.s 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. Ma.s.s 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. Ma.s.s 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. Ma.s.s 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_, Ma.s.s., 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 cl.u.s.ters, or scattered, without any hypothallus; the wall brown, smooth and shining. Ma.s.s 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 Plata.n.u.s, 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. Ma.s.s 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. Ma.s.s 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 papillae, 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 cl.u.s.ters of cylindrical openings or pits, or are sculptured into intricate plexuses of minute reticulations with quadrilateral inters.p.a.ces."

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. Ma.s.s 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. Ma.s.s 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.

IV. OLIGONEMA, Rost. Sporangia subglobose, more or less irregular, sessile and closely crowded, often in heaps, one upon another, the wall thin, smooth and shining; hypothallus none. Capillitium scanty, composed of elaters habitually irregular and abnormal, intermingled with the spores; elaters simple or sometimes branched, commonly very short, but varying greatly in length, even in the same sporangium; the surface marked with faint spirals, with a few annular ridges, minutely punctulate or altogether smooth. Spores globose, yellow.

The species of this genus are to be regarded as degenerate Trichias. Of course, the abnormality is exhibited most markedly by the elaters; nevertheless, the sporangia of some of the species have a peculiar habit of heaping themselves upon each other.

_A. Surface of the spores reticulate._

_a. Elaters with projecting rings._

1. OLIGONEMA NITENS, Lib. Sporangia subglobose, irregular, sessile, closely crowded and heaped upon each other, the wall thin, yellow, smooth and shining. Ma.s.s of capillitium and spores yellow; elaters simple or sometimes branched, 3-4 mic. in thickness, with a few distant projecting rings, the surface smooth between, or with very faint spirals, the extremities obtuse, or sometimes with a minute apiculus.

Spores angularly or irregularly globose, the surface reticulate, 11-14 mic. in diameter.

Growing in small patches on and within rotten wood. Sporangia .4-.5 mm.

in diameter; the elaters variable, some with as many as a dozen projecting rings, some with but a few or nearly smooth. _Trichia nitens_, Libert.

2. OLIGONEMA PUSILLA, Schr. Sporangia subglobose, irregular, sessile, scattered or collected together in heaps; the wall thin, yellow, smooth and shining. Ma.s.s of capillitium and spores yellow; elaters simple or sometimes branched, 4 mic. in thickness, sometimes with thicker inflated portions, the surface marked with low faint spirals or perfectly smooth; the extremities rounded and usually terminating in a smooth point, 3-5 mic. in length--this point either curved, bent to one side or turned back, and twisted around the extremity as a ring. Spores angularly or irregularly globose, the surface reticulate, 11-14 mic. in diameter.

Growing in small cl.u.s.ters in rotten wood. Sporangia .3-.5 mm. in diameter; the elaters variable in length, scarcely exceeding 100 mic.

and often much shorter. _Trichia pusilla_, Schroeter.

_b. Elaters with no projecting rings._

3. OLIGONEMA FLAVIDUM, Peck. Sporangia obovoid to oblong, sessile, closely crowded and irregular from mutual pressure; the wall thin, yellow, shining, punctulate or minutely granulose. Ma.s.s of spores and capillitium yellow; elaters simple or sometimes branched, 3-4 mic. in thickness, sometimes with thicker inflated portions; the surface punctulate or minutely warted, occasionally marked with very faint spirals; the extremities usually rounded and obtuse, sometimes acute, and rarely with a minute apiculus. Spores angularly or irregularly globose, the surface reticulate, 11-14 mic. in diameter. See Plate I, Fig. 24.

Growing in dense patches on old wood and mosses. Sporangia .4-.6 mm. in diameter, and reaching 1 mm. in height, the elaters usually rather long, sometimes quite long and branched.

4. OLIGONEMA BREVIFILA, Peck. Sporangia subglobose, irregular, sessile, crowded, forming cl.u.s.ters or effused patches; the wall thin, yellow, densely granulose and venulose. Ma.s.s of capillitium and spores ochre-yellow; elaters simple or sometimes branched, often very short and fusiform, when elongated having long tapering extremities, sometimes with irregular swollen portions; the surface minutely granulose and rugulose, here and there a few spinules, occasionally with indistinct spirals. Spores angularly or irregularly globose, the surface reticulate, 11-12 mic. in diameter.

Growing on old wood and mosses. Sporangia .4-.5 mic. in diameter, the elaters varying greatly in length, some not more than 20 or 30 mic.