DIACHEOPSIS 187 



or solely from the summit of the columella, when latter is present, 

 otherwise from the base of the sporangium. 



The typical members of this family are very close to the Stemoni- 

 tacea?. Certain species of Lamproderma and of Comatricha approach 

 the other genus rather closely. In general, however, the lamproder- 

 mas have the capillitial branches concentrated at or near the tip and 

 possess a more persistent and usually iridescent membrane. 



The genus Diacheopsis, judging from the description, is a sessile 

 or nearly sessile lamproderma without columella. Echinostelium 

 may or may not belong in this family, but may at least be tempo- 

 rarily accommodated. 



KEY TO THE GENERA OF THE LAMPRODERMACE^E 



a. Sessile on a broad base or short-stalked; columella lacking. . 1. Diacheopsis 

 a. Stipitate, or rarely sessile on a narrowed base; columella 



present " 



b. Columella percurrent; capillitium arising from a disk at 



its apex 2. Enerthenema 



b. Columella rarely exceeding the center of the sporangium c 



c. Columella very short; capillitium forking but not forming a 



net d 



c. Columella \i to Y 2 the height of the sporangium « 



d. Minute, 100 n or less in height; capillitium rudimentary. . 3. Echinostelium 

 d. Larger; capillitium brush-like, rigid, the threads bearing 

 circular disks at their tips derived from the sporangium 

 wa ll 4. Clastoderma 



e. Peridium dark, dehiscing in persistent lobes; capillitium dark, 



scanty, simple 5. Barbeyella 



e. Peridium iridescent, fragile; capillitium dense, often branch- 

 ing and anastomosing freely 6. Lamproderma 



1. Diacheopsis Meylan 

 Bull. Soc. Vaud. Sc. Nat. 57 : 149. 1930. 



Sporangia globose, sessile or stalked; peridium membranous, per- 

 sistent, shining with metallic luster; columella lacking; capillitium of 

 branching and anastomosing threads as in Lamproderma, but these 

 arising from the base of the sporangium; spores dark. 



Except for the absence of a columella the genus appears to be very 

 close to Lamproderma. 



A single species: — 



Diacheopsis metallica Meylan 



Bull. Soc. Vaud. Sc. Nat. 57 : 149. 1930. 

 Sporangia clustered, subglobose, sessile, broader than high, 1-2 mm. 

 in diameter, dark blue, with metallic green, pale blue, purple or gold 



