The North American Slime-Moulds Part 65

Widely distributed. New England to Colorado, south to Mexico.

9. HEMITRICHIA STIPITATA (_Ma.s.s._) _Macbr._

1889. _Hemiarcyria stipitata_ Ma.s.s., _Jour. Mic. Soc._, p. 354.

1893. _Hemiarcyria plumosa_, Morg., _Jour. Cin. Soc._, p. 29.

Sporangia scattered, seldom crowded, obovoid or turbinate, olivaceous yellow, stipitate; the peridium smooth without, granulose within, evanescent above, persisting as a funnel-shaped cup below; the stipe long, reddish or blackish, rising from a small hypothallus; capillitium of threads 5-6 thick, very much branched, forming a dense net, free ends none, or not evident; the sculpture as in _H. clavata_, smooth and regular; spore-ma.s.s yellow; spores by transmitted light yellow, minutely warted, 7-8 .

This form corresponds in nearly every respect with _H. clavata_, except in the structure of the capillitium. The color is rather ochraceous, dirty yellow, and the stipe is proportionally longer and darker, but the form of the net is positive and gives to the species a decidedly striking and unique appearance, so that it may be recognized by the naked eye. It looks like an arcyria and for this reason Professor Morgan said _H. plumosa_. Lister regards it as the same as our number 8.

Common. Ohio, Illinois, Missouri, Iowa, and west; south to Mexico.

10. HEMITRICHIA MONTANA _Morgan._

Sporangia scattered or gregarious more or less closely, globose, whitish, sessile or very short stipitate; the peridium opaque, dull white, persistent below; capillitium deep yellow, the threads abundantly branched, forming a compact network, 7 wide, bearing spirals five or six, uneven and irregular, or anon interrupted, conspicuously spinulose or warted, free tips not lacking, generally inflated; spore-ma.s.s yellow, spores by transmitted light pale, nearly colorless, distinctly warted, 10 .

Recognizable by its peculiar pallid, sessile sporangia, as by the internal structure. Perhaps related to _Hemiarcyria bucknalli_ Ma.s.s. Our specimens are from Mr. Morgan, of Ohio, with the statement that they were collected in the San Bernardino Mountains, California, by Mr. S. B.

Parrish; collected later from Monterey south.

Common throughout south-western states to lower California.

=2. Calonema= _Morgan._

1893. _Calonema_ Morgan, _Jour. Cin. Soc._, p. 33.

Sporangia sub-globose, crowded or superimposed, irregular sessile; hypothallus none; capillitium of slender tubules, arising from the sporangium base, branched, marked with branching veins in an irregular reticulation, and terminating in free extremities. Spores yellow.

1. CALONEMA AUREUM _Morgan._

PLATE XIII., Figs. 2, 2 _a_, 2 _b_, 2 _c_.

1893. _Calonema aureum_ Morgan, _l. c._

Sporangia crowded or heaped in scattered cl.u.s.ters; peridium thin, golden yellow, adorned with intricate radiating veinlets capillitium of threads more or less branched, attached below, free above, the surface to the very tips venulose, interrupted with rings or fragmentary spirals, the apices bulbous and obtusely conical; spore-ma.s.s yellow, spores by transmitted light bright yellow, covered by a network of interlocking plates, as in _T. favoginea_, globose, 14-16 .

A curious form, related to _Hemitrichia_, much as _Oligonema_ is to _Trichia_. Related to both the genera first named, but distinct, in the peculiar sculpture, from _Hemitrichia_, and from _Oligonema_ in that the threads are not entirely free. Professor Morgan's original determination, founded on Ohio materials is confirmed by material sent us by Professor Underwood from Alabama.

=3. Trichia= (_Haller_) _Rost._

1768. _Trichia_ Haller, _Hist. Stirp. Helv._, III., p. 114, in part.

1875. _Trichia_ (Haller) Rost., _Mon._, p. 243.

Sporangia distinct, sessile or stipitate; capillitium of distinct elastic threads, free ac.u.minate at each end, yellow or more rarely reddish or brown; spores generally yellow.

The trichias are easily recognized among their kind by their beautiful spirally wound, elastic capillitial threads, the _elaters_; these are entirely free, about 3-4 mm. in length, simple or only rarely branched, and generally acute at each extremity. The spiral bands, sometimes called _taeniae_, are generally very uniform in thickness, distance from each other, and pitch, and in many species are further reenforced by minute longitudinal plications running from one spiral to the next.

Furthermore, the spirals may be smooth or spinulose the elater uniform throughout or enlarged betimes by nodes and swellings. Taken altogether, the trichias with the species of the genus next following exhibit the highest degree of differentiation attained by the Myxomycetes.

Most of the earlier authors, including Haller, used the generic name _Trichia_ to cover a variety of forms. It is here used with the limits sketched by De Bary in 1859 and 1864 (_Die Myxomyceten_), and followed more exactly ten years later by his pupil, Rostafinski.

=Key to the Species of Trichia=

_A._ Sporangia, in typical cases at least, wholly sessile.

_a._ Gregarious; hypothallus none.

i. Peridium brown or reddish brown.

O Elaters smooth.

OO Spirals even, regular 1. _T. inconspicua_

+ Spirals irregular 2. _T. contorta_

++ Elaters rough, spinescent 3. _T. iowensis_

ii. Peridium olivaceous or yellow.

O Elaters smooth 4. _T. varia_

_b._ Hypothallus distinct; sporangia crowded; spores reticulate, banded, or netted.

i. Spore-bands pitted 6. _T. persimilis_

ii. Spore-bands, narrow, plain 7. _T. favoginea_

iii. Spores covered by a delicate net 5. _T. scabra_

_B._ Sporangia stipitate.

_a._ Hypothallus distinct 8. _T. verrucosa_

_b._ Hypothallus none; peridium checkered with pale reticulations.

i. Brownish red or black 10. _T. botrytis_

ii. Olivaceous.

O Elaters smooth 11. _T. subfusca_

OO Elaters rough 12. _T. erecta_

_c._ Peridium plain, s.h.i.+ning 13. _T. decipiens_