TRICHIA 209 



A curious form, related to Hemitrichia, much as Oligoncma 

 is to TricJiia. Related to both the genera first named, but dis- 

 tinct, in the peculiar sculpture, from HcmitricJiia 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 (Hatter) Rost. 



1768. Trichia Haller, Hist. Stirp. Helv., III., p. 114 (in part). 

 1875. Trichia (Haller) Rost, Man., p. 243. 



Sporangia distinct, sessile or stipitate ; capillitium of distinct 

 elastic threads, free, accuminate 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 tcenice, 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 Myxomy- 

 ceten\ 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. 

 * Elaters smooth. 

 f Spirals irregular . . . 2. T. contorta 



