84 Mycetozoa of Nqrth America 



Genus 5. PHYSARELLA Peck, Bull. Torr. Bot. Club 9: 61. 

 1882. 



Sporangia stalked, shortly cylindrical or bell-shaped, hollow, 

 or forming plasmodiocarps; exterior part of sporangial wall 

 studded with long, spike-like processes on the inner side; interior 

 part persisting as a hollow columella after dehiscence. Capil- 

 litium of slender threads with few lime-knots, or many if the 

 processes are absent. 



A SINGLE SPECIES. 



1. Physarella oblonga (Berk. & Curt.) Morg. Jour. Cin. Soc. 

 Nat. Hist. 19: 7. 1896. 



rric^am^/zora o6/owga Berk. & Curt.; Berk. Grevillea 2: 66. 1873. 

 Physarella mirabil is Peck, Bull Torr. Bot. C\uh 9: 6\. 1882. 



Plasmodium rich yellow (Lister). Total height up to 3 mm. 

 Sporangia gregarious, stalked, inclined or nodding, shortly cylin- 

 drical, 0.6 to 1 mm. long, 0.4 to 0.6 mm. broad, cup-shaped or 

 funnel-shaped, hollow, or sometimes forming twisted and con- 

 torted sporangia and similar plasmodiocarps, olive-brown or red- 

 dish brown, speckled with small, yellow spots; sporangial wall a 

 stout yellow membrane, thickened with yellow lime-granules, the 

 exterior part attached to the stalk and studded on the inside with 

 long, yellow or orange, spike-like, calcareous processes, extending 

 toward the interior part, which is a continuation of the stalk, and 

 persists as a long, hollow columella after dehiscence at the rim of 

 the cup-like sporangium. Upon dehiscence, the outer part of the 

 wall recurves in lobes at right angles to the stalk, exposing the 

 spike-like processes extending outward. Stalk cylindrical, striate, 

 red-brown, translucent, slender, broader at the base, 1 to 2 mm. 

 high, or thick and irregular. Capillitium consisting of many 

 forking, slender, pale yellow threads, with few small, fusiform, 

 yellow lime-knots, or in sessile and plasmodiocarpous forms where 

 the processes may be absent, a network of yellow threads with 

 large irregular yellow or orange lime-knots. Spores violet-brown, 

 almost smooth, 6-8 n diam. (Plate 8, fig. 5.) 



Type locality: Pennsylvania. 



Habitat: On dead wood and piles of decaying vegetable 

 matter. 



Distribution: Distributed throughout North America and 

 not uncommon. 



