220 



Haynes : The genus Sphaerocarpos 



consisting of a single layer of cells destitute of spiral, annular, or 

 other local thickenings. Spores permanently united in tetrads 

 with two exceptions, S. Domicilii, in which they become free at 

 full maturity and 5. crislatus, in which they separate early in the 

 development of the sporogonium ; spore-tetrads, when persistent, 

 distinctly areolate, appearing crenulate, papillate or subechinulate 

 in optical section ; spores, when separate, compressed-tetrahedral, 

 rounded-lenticular, or sometimes concavo-convex, areolate or 

 cristate, in 5. Donnellii prominently tuberculate in the basilar cir- 

 cumference. Accompanying the spore mother-cells are smaller 

 starch-bearing sterile cells probably equivalent to elaters morpho- 

 logically, but lacking a spiral band, these more or less shriveled 

 and obscure at the maturity of the spores. 



Type species, Sphaerocarpos Sphaerocarpos (Dicks.) M. A. 



Howe. 



Key to the species of Sphaerocarpos 



9 involucre sessile or subsessile. 



Spores permanently united in tetrads. 



9 involucre contracted at the apex, the diameter of its 

 orifice much less than that of the involucre ; 

 spore-tetrad regularly areolate. 

 9 involucre pyriform, obovoid, or subglobose ; 

 meshes of spore-tetrad J-I^fi in diameter, the 

 separating ridges low except at their intersections 

 where they are raised into very acute or acicular 

 spicules. 

 9 involucre tubular, fusiform-clavate, or rarely 

 subpyriform ; meshes of spore-tetrad 15-30 // in 

 diameter, the separating ridges usually high, 

 sinuous, crenulate, or dissected, or sometimes 

 raised to blunt spines at their intersections. 

 9 involucre wide-mouthed, the diameter of its orifice 

 equaling or often exceeding that of the subjacent part 

 of the involucre. 

 Spores separating at maturity, 85-138/^ in maximum diam- 

 eter, areolate, each while united in the tetrad commonly 

 showing a prominent protuberance about 12 fi high in 

 middle of outer face, and after separation exhibiting a 

 coarsely lobed basilar margin. 

 Spores separating long before maturity, 52-80// in maximum 

 diameter, typically cristate, less commonly irregularly and 

 sparingly areolate. 

 9 involucre distinctly stipitate. 



I. S. Sphaerocarpos. 



2. S. texanns. 



S. hians. 



4. S. Donntlli. 



5. S. cri status 



6. S. stititatus. 



I. Sphaerocarpos Sphaerocarpos (Dicks.) M. A. Howe, Mem. 



Torrey Club 7 : 66. 1899. [With the -us ending.] 



Targionia Sphaerocarpos Dicks. PI. Crypt. I: 8. 1785. — D.C. 



Fl. Fr. 2: 419. 18 1 5. --Poll. Fl. Veron. 3: 399. 1824. 



