220 Haynes: THE GENUS SPHAEROCARPOS 
consisting of a single layer of cells destitute of spiral, annular, or 
other local thickenings. Spores permarently united in tetrads 
with two exceptions, S. Doznelliz, in which they become free at 
full maturity and S. cristatus, 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 S. Donnellfii 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 
© involucre sessile or subsessile. 
Spores permanently united in tetrads. 
Q involucre contracted at the — the diameter of its 
orifice much less than that of the involucre; 
spore-tetrad regularly areolat 
© involucre pyriform, Sa: or subglobose ; 
m of spore-tetrad 7-15 in diameter, the 
eataie ridges low except at their intersections 
where they are raised into very acute or acicular 
spicules. 1, S. Sphaerocarpos. 
.e) involucre tubular, fusiform-clavate, or rarely 
raised to blunt spines at their intersections. 2. S. texanus, 
2 involucre wide-mouthed, the diameter of its orifice 
equaling or often exceeding that of the subjacent part 
he involucre, . S. hians. 
Spores separating at maturity, 85-138 u in maximum diam- 
showing a prominent protuberance about 124 high in 
middle of outer face, and after separation exhibiting a 
coarsely lobed basilar margin 4. S. Donnelli. 
Spores separating long before ciitasiey, 52-80 ” in maximum 
diameter, typically cristate, less commonly irregularly and 
sparingly areolate 5. S. cristatus 
2 involucre distinctly stipitate. 6. S. stipitatus. 
I. SPHAEROCARPOS SPHAEROCARPOS (Dicks.) M. A. Howe, Mem. 
Torrey Club 7: 66. 1899. [With the -ws ending. ] 
Targionia Sphaerocarpos Dicks, P|. Crypt. 1: 8. 1785. — D.C. 
Fl. Fr. 2: 419. 1815.— Poll. Fl. Veron. 3: 399. 1824. 
