1922] 



PFEIFFER — MONOGRAPH OF THE ISOETACEAE 111 



Corm 3-lobed; leaves 10-40 (rarely 60). 12-40 cm. long, light 

 green, firm but not stiff, tapering to apex, with wide membrana- 

 ceous margin at base gradually narrowed to disappearance 1-2 

 cm. above sporangium level; stomata present in upper parts of 

 leaves; peripheral strands variable, but chiefly 6 plus accessory 

 strands ; ligule longer than wide ; sporangia 4-6 mm. long, lightly 

 marked with sclerenchyma cells ; velum none ; megaspores white, 

 564-680 n (rarely 800) in diameter, densely crowded on all faces 

 with small warts or tubercles ; commissural ridges prominent and 

 wide ; microspores 27-37 m long, usually with slightly crenulate 

 margins and with low crest. 



Distribution: Montpellier, Herault, France. 

 Specimens examined : 



France: Grammont, near Montpellier, December, 1820, Ballard 



(Gray Herb.) ; Montpellier, ex Herb. Engelmann (Mo. Bot. 

 Gard. Herb.) ; mare de Grammont pres Montpellier, Delile 

 (N. Y. Bot. Gard. Herb.); lac de Grammont. August, 1S37, 

 de Gerard (Mo. Bot. Gard. Herb.) ; Montpellier, Grammont, 

 21 March, 1840, Bubani (U. S. Nat. Herb.); Montpellier, 

 1842, Wanderley (Mo. Bot. Gard. Herb.); Montpellier, 

 Grammont, 30 June, 1X12, without collector (Mo. Bot. Gard. 

 Herb.) ; pools of plateau of Roquehaute, 7 June, 1863, Durieu 

 21 (N. Y. Bot. Gard. Herb.) ; pond near Montpellier, 8 June. 

 1857, Cosson (Gray Herb., Mo. Bot. Gard. Herb., and N. Y. 

 Bot. Gard. Herb.); near Beziers (Herault), and Juire, 1879, 

 Gautier (N. Y. Bot. Gard. Herb.) ; Montpellier, 1866, Cosson 

 (Mo. Bot. Gard. Herb.) ; marsh, Roquehaute near Beziers 

 (Herault), 3 June, 1862, Cosson (Mo. Bot. Gard. Herb., N. 

 Y. Bot. Gard. Herb., and Gray Herb.) ; pool, Roquehaute, 

 June, 18(i2, Durieu (Mo. Bot. Gard. Herb.); "in almost all 

 the ponds of the volcanic plateau of Roquehaute, Herault/' 

 17 May, 1S64, Motelay (Mo. Bot. Gard. Herb.); ponds of 

 Roquehaute, 11 May, 1864, Cheveneau (U. S. Nat. Herb.); 



pond of Roquehaute near Beziers, June, 1869, Cheveneau 

 (Gray Herb.); near Montpellier, Grammont, 6 June, 1884, 



without collector (U. S. Nat. Herb.); pond at Grammont 



near Montpellier, November, 1876, Duval-Jouve (Gray 



Herb.) ; Grammont near Montpellier, 10 May, 1888, Herb. 



Fac. Sclent. Monsp. (U. S. Nat. Herb.) ; Portiragnes 



(Herault), ponds in plateau of Roquehaute, 1 April, 1888, 



