DiDYMIACEAE 115 



to D. caespitosa, but differs in having spores that are reticulated 

 with small spines. 



8. Diachea caespitosa (Sturg.) A. & G. Lister, Jour. Bot. 45: 186. 

 1907. 



Comatricha caespitosa Sturg. Bot. Gaz. 18: 186. 1893. (N. Y. B. G. no. 

 12698, type.) 



Plasmodium orange-yellow. Sporangia in clusters of six to 

 thirty, sessile or short-stalked, cylindrical or clavate-cylindrical, 

 0.7 to 1.5 mm. high, 0.5 mm. thick, iridescent blue or bronze; 

 sporangial wall membranous, colorless, soon breaking away above, 

 more persistent below. Stalk slender, dark brown, very short, 

 without lime, rising from a yellowish membranous hypothallus. 

 Columella without lime, a slender membranous wrinkled tube, 

 brown below, yellowish above, reaching nearly to the apex of the 

 sporangium. Capillitium a network of purple-brown threads, 

 spreading from all parts of the columella. Spores pale purplish 

 gray, 9-11 n diam., marked with small, scattered warts, and 

 several clusters of stronger warts. 



Type locality: Massachusetts. 



Habitat: On mosses. 



Distribution: Maine, Massachusetts, New Hampshire, 

 *North Carolina, Ontario. 



Illustration: Lister, Mycetozoa ed. 3. pi. 103, jigs. f-j. 



Related to D. cylindrica, it differs in the spore characters. 

 The form is rare, and the collection by Mr. Eli Davis at Byron, 

 Ontario, in 1940, was the first in over 30 years. D. cylindrica 

 and D. caespitosa connect the genera Diachea and Lamproderma, 

 having the thin, iridescent, persistent, sporangial walls common 

 to species of both genera, and the tubular stalks and columellae 

 of Diachea, although free from lime. Limeless forms are found 

 occasionally in several species of the genus Diachea. The two 

 forms have only a superficial resemblance to Comatricha, where 

 the sporangial wall is of a different nature, and more or less 

 evanescent with complete maturity of the sporangia. 



Family H. DIDYMIACEAE 



Deposits of lime in the form of crystals or crystalline discs 

 distributed over the sporangial wall; capillitium without lime- 

 knots (except in Didymium Sturgisii) ; sporangia simple, except 

 in Mucilago, where they are combined into an aethalium. 



