1860. _Trichia metallica_ Berk. Hook., _Fl. Tasm._, 2, p. 168.

1866. _Trichia flagellifera_ Berk. & Br., _Ann. Mag. Nat. Hist._, 3, XVII., p. 56.

1876. _Prototrichia flagellifera_ (Berk.) Rost. _Mon. App._, p. 38.

1894. _Prototrichia flagellifera_ Rost., List., _Mycet. 2nd ed._, p. 206.

1899. _Prototrichia flagellifera_ (Berk. & Br.) Rost., Macbr., _N. A. S._, p. 199.

1892. _Prototrichia metallica_ Ma.s.s., _Mon._, p. 127.

1911. _Prototrichia metallica_ Ma.s.s., List., _Mycet., 2nd ed._, p. 260.

Sporangia sessile, scattered or sometimes crowded, brown, sometimes with a rosy tinge, about 1 mm. in diameter; peridium a thin, transparent, iridescent membrane, bearing in its inner surface the distal attachments of the capillitial threads; capillitium of numerous brown, spirally banded threads, which take origin in the base of the sporangium, become subdivided as they ascend, and are at length attached by their tips to the sporangium wall; spore-ma.s.s brown, spores by transmitted light pale, minutely roughened.

This curious form, with its spirally sculptured capillitial threads attached at both ends, stands intermediate between _Dianema_ and _Hemitrichia_ and _Trichia_. Berkeley called it a trichia, ignoring the attachment of the threads. Cooke notes this as sufficient to exclude the form from the genus. But it remained for Rostafinski to make the transfer by setting up for its reception the genus now adopted. He preferred the later (1866) specific name as more descriptive. Miss Lister reverts to the earlier name with the remark; "Little now remains of the type _Prototrichia metallica_ Berk. from Tasmania; but the specimen is referred to _Prototrichia flagellifera_ by Rostafinski who saw it in good condition."

Not uncommon in the abietine forests of the West. Alberta, Oregon, Washington, California, Nevada, Montana, Idaho, Colorado.

_E._ TRICHIACEae

Capillitium marked by spiral bands, sometimes scattered rings, etc., the threads entirely free, or at least loosely branched, and with free tips more or less numerous.

=Key to the Genera of the Trichiaceae=

_A._ Capillitium threads long, generally united to form a loose net, centrally attached.

_a._ Sculpture spiral 1. _Hemitrichia_

_b._ Sculpture reticulate 2. _Calonema_

_B._ Capillitial threads shorter, entirely free, though sometimes branched.

_a._ Threads, elaters, marked by spiral bands 3. _Trichia_

_b._ Sculpture irregular or wanting 4. _Oligonema_

=1. Hemitrichia= _Rost._

1829. _Hemiarcyria_ Fries, _Syst. Myc._, III., p. 183 in part.

1873. _Hemitrichia_ Rost., _Versuch_, p. 14.

Capillitium a tangled net of more or less branching and anastomosing fibres centrally attached; the sculpture regular, of conspicuous spirally winding bands or ridges; habit and color various.

The species here a.s.sociated are intermediate between _Arcyria_ and _Trichia_, resembling the former in the capillitial net and the latter in thread-sculpture. Fries applied the name _Hemiarcyrieae_ to a group of trichias so-called, citing _H. rubiformis_ as the first. In his _Versuch_ Rostafinski wrote _Hemitrichia_ and afterward _Hemiarcyria_ in the _Monograph_. Ma.s.see combines the genera _Arcyria_ and _Hemiarcyria_ under the former name.

=Key to the Species of Hemitrichia=

_A._ Plasmodiocarpous

_a._ Plasmodiocarp net-like, yellow 1. _H. serpula_

_b._ Imperfectly plasmodiocarpous, brown 2. _H. karstenii_

_B._ Sporangia all distinct.

_a._ Sessile; very short stalked

i. Peridium hyaline, iridescent 3. _H. ovata_

ii. Peridium opaque 10. _H. montana_

_b._ Stipitate, generally distinctly so; sometimes nearly sessile.

i. Yellow or ochraceous.

O Stalk hollow.

+ Small, mm., iridescent 6. _H. leiocarpa_

++ Larger, 1 mm., smooth but not iridescent

1. Free ends more or less abundant 8. _H. clavata_

2. Free ends none 9. _H. stipitata_

OO Stalk solid 7. _H. intorta_

ii. Not yellow.

O Ruby red 4. _H. vesparium_

OO Copper-colored 5. _H. stipata_

1. HEMITRICHIA SERPULA (_Scop._) _Rost._

PLATE III., Figs. 4, 4 _a_, 4 _b_.

1772. _Mucor serpula_ Scop., _Fl. Carn_, II., p. 493.

1794. _Trichia serpula_ (Scop.) Pers., _Rom. N. Bot. Mag._, I., p. 90 1875. _Hemiarcyria serpula_ (Scop.) Rost., _Mon._, p. 266.

Fructification plasmodiocarpous, often covering several square centimetres, terete, branching freely and usually everywhere reticulate, rusty, tawny, or bright yellow; the peridium thin, transparent, with irregular dehiscence; hypothallus none; capillitium variable, a tangle of long yellow threads, sparingly branched, free everywhere, except below, spinulose, the free tips spinose, ac.u.minate, spiral ridges three or four, with traces of longitudinal striae; spore-ma.s.s golden yellow, spores beneath the lens pale yellow, globose, delicately reticulate, about 10 .

Very common, recognized by its bright yellow color and conspicuous reticulate habit. The plasmodium is yellow, at least upon emergence, and pa.s.ses almost without change to fruit. Found on rotten logs of every description, on the _lower_ surface. In the Mississippi valley, the lower surface of planks used in the construction of sidewalks appears to be a favorite habitat.

Common west to the Rocky Mountains, south to Mexico and Nicaragua.

2. HEMITRICHIA KARSTENII (_Rost._) _List._

1876. _Hemiarcyria karstenii_ Rost., _Mon., App._, p. 41.