164 THE AMERICAN MONTHLY [September, 



§§ End view 5 or 6-angled, apices of (6) rays rounded and spiirulose, 



Kissiin 7n ense . f 

 §§ " " f ajjices of (5-6) rays trifid, distended, 



distent ufii^ 149. 

 §§ End view S-angled ; rays a whorl of 8 below^, 4 above, tetroctocerum^ 151 . 

 §§ End view circular, rays a whorl of 9 below, 6 above, . artiscon^ 148. 

 §§ "■ " rays marginal, very short, usually 9, ends notched, 



Eloiseanum^ 149. 

 I. Angles of semi-cell in front view not produced ; rounded and smooth (a) . 

 I, " " " " " '^ mucronate, spinous or 



notched (c) . 



1. Angles of semi-cell in front view produced more or less (/^). 

 3. Angles of semi-cell in front view more or less produced (/). 



2. " '' '' *•' '' '" not produced i^gg) • 



3. Angles of semi-cell in front view more or less produced {00). 



3. " " " " " "• not produced (jKy)- 



a. Semi-cell oval or elliptical ; diameter ^^77 ^'^ tsVo" "^' K^'h~^^'>'-) 



miitic?e?n^ 119; minor ^ 119; Bieneanuiti^ 124. 



a. Semi-cell oval or elliptical; diameter ^1,^ to ^\-^ in. (60-112//) ((5). 



a. Semi-cell semicircular; sinus narrow, linear. . . orbiadare^ \20. 



a. " triangulare, sides concave tri'hedralc, 123. 



a. " subcuneate ; cell slightly longer than wide, 



pseudopachyrhynchutti^ 125. 



b. Sides slightly constricted near the angles, especially in end-view, 



ttimiduin., 120. 

 b. Sides not constricted ; diameter -^\-^^ to -^^-^ in. (7'i~S3'/) grande^ 120. 



b. "• "■ '' diameter ^^\-^ in. (60//.) .... inerme^ 122. 



c. Angles mucronate {d ) . 



c. Angles aculeate, spinous, awned or notched {e) . 



d. Mucros double on basal angles, none on the end in front view ; semi-cells 



truncated triangles, paniculosum^ 124. 



d. Mucros single on all angles, horizontal ; diameter less than ^i^ in. (50//) ; 



semi-cells not quadrangular brevispina^ I2i. 



d. Mucros single on all angles, horizontal ; semi-cells quadrangular, 



quadrangnlai-c, 145. 

 d. Mucros single on all angles, diameter larger than -^\-j^ (50,'j) •, 



fnagnu7n, 120. 



d. Mucros single, o])lique downward and inward: diameter ^t^- (lOO//) or 



more niajuscuhim^ 121. 



d. Mucros single, oblique downAvard and out\vard ; diameter ^^ (45/^-) oi' 



less Dickiei^ 122. 



e. Aculei or awns i on each angle (y") . 

 e. " 2 on each angle (^). 

 e. " 3 on each angle {vv) . 



e. " 4 or more on each angle {zvzv) . 



f. Semi-cells elliptical, often angular, approximate ; ends straight, concave 

 or convex ; awns horizontal, diverging, converging or upwardly ob- 

 lique ; diameter g-|-g- to yqJq^^ in. (25-3S//) .... dejectum, 121. 

 y. Semi-cells elliptical, separated by a long, narrow isthmus, 



cuspidatum^ 123. 

 _/". *' triangular-fusiform; awns long ; diameter ^^j^ to j^-g (50-57,'/) 



fnegacanthum , 121. 



t Bulletin Torrey Botknical Club, Dec, 1885. 



