Arcyria 255 



The two phases of the sporangia have intermediate forms con- 

 necting them but are usually clearly distinguished. The species 

 is also connected with A. occidentalis by forms with the general 

 characters of A. stipata, but with deeper cups which may show 

 occasionally a slight tendency to the petaloid dehiscence of A. 

 occidentalis. The spirals on the threads of the capillitium of A. 

 stipata are similar to those of other species of the genus, only often 

 more prominent, and are not like those in the genus Ilemitrichia. 



11. Arcyria nutans (Bull.) Grev. Fl. Edin. 455. 1824. 



Trichia nutans Bull. Herb. Fr. pi. 502, fig. 3. 1790; Bull. Champ. 122. 1791. 



Plasmodium watery white (Lister). Sporangia stalked, clus- 

 tered, cylindrical, when unexpanded 1.5 to 2 mm. high, 0.3 to 0.5 

 mm. broad, yellow or buff; cup of sporangium membranous, flac- 

 pid, reticulate and often spinulose on the inner side, interruptedly 

 plicate. Stalk buff, short or elongate, weak, filled with spore- 

 like cells. Capillitium an elastic network of pale yellow, terete 

 or flattened threads 3-4 m diam., expanding into a drooping 

 column 8 to 12 mm. long, free from the cup or with few attach- 

 ments; thickenings on the threads in the form of sharp spines and 

 half-rings arranged in a loose spiral, and of scattered spinules and 

 short lines of broken reticulation ; free ends more or less numerous, 

 clavate. Spores pale yellow, nearly smooth, marked with a few 

 scattered warts, 6-8 m diam. (Plate 16, fig. 15.) 



Type locality: France. 



Habitat: On dead wood. 



Distribution: Common throughout North America. 



Illustration: Lister, Mycetozoa ed. 3. pi. 179. 



12. Arcyria magna Rex, Proc. Acad. Nat. Sc. Phila. 1893: 364. 

 1893. (N. Y. B. G. no. 5198, type material.) 



Plasmodium? Sporangia stalked, clustered, cylindrical, when 

 unexpanded 1.5 to 2 mm. high, 0.3 to 0.5 mm. broad, gray, often 

 forming large developments; cup of sporangium funnel-shaped, 

 membranous, flaccid, plicate, spinulose or papillose on the inner 

 side. Stalk short or long, somewhat membranous and irregular, 

 yellowish or brownish, filled with spore-like cells, and arising from 

 a yellowish membranous hypothallus. Capillitium an elastic 

 network of grayish threads 3-4 fx diam., expanding into a drooping 

 column up to 12 mm. or more in length, free from the cup or with 



