1922] 



PFEIFFER — MONOGRAPH OF THE ISOETACEAE 185 



Herb.) ; Kingston, September, 1897, Eaton 942 (Mo. Bot 

 Gard. Herb.). 



Massachusetts: Uxbridge, 1845, Robbins 10 (Mo. Bot. Gard 



Herb.); Watson's Pond, Taunton, 15 September, 1903, Ea- 

 ton (Mo. Bot. Gard. Herb.) ; Leach's Pond (Wilbor's Pond) 

 (Mass.?), September, 1906, Eaton (Mc. Bot. Gard. Herb.) 

 Uxbridge, 31 August, 1907, Eaton (Mo. Bot. Gard. Herb.) 

 rare, muddy shores, pool in Peabody Cemetery, 10 October, 

 1915, Andrews (Gray Herb.). 



Connecticut: half submerged on shore of Chapman's Pond, Gro- 



ton, 30 August, 1896, Graves 144 (Mo. Bot. Gard. Herb.); 



mill-race in Mill River, Fairfield, 19 July, 1905, Eames 5294 

 (Gray Herb.). 



New Jersey: Pt. Pleasant, September, 1899, Best (Mo. Bot. 



Gard. Herb.); Pt. Pleasant, 4 July, 1899, Best & Crawford 



Th 



Gard. Herb.) 



distinction 



based chiefly on the tendency to larger size in the variety which 

 is evinced in more and longer leaves. There is also an inclina- 

 tion toward larger microspores, though the ranges overlap suf- 

 ficiently so that this too cannot be used absolutely. The Ux- 

 bridge material of Robbins is of the intermediate sort, with 

 somewhat bigger microspores, but plant size according well with 

 the general range of the soecies. 



49. 1. Pringlei Underw. Zoe 1 : 98. 1890. 



Corm 2-lobed; leaves 4-20, 16-30 cm. long, firm, fine, taper- 

 ing, with membranaceous margin only briefly extended (1 cm.) 

 above level of the sporangium; stomata abundant; peripheral 

 strands numerous, 6 conspicuous and 6-10 accessory groups; 

 ligule triangular, short and wide; sporangium large, up to 10-12 

 mm. in length in large individuals, partly covered by narrow 

 velum ; megaspores chalky white when dry, tan when moist, 460- 

 550 p in diameter, rarely 650 \i, marked with high tubercles, oc- 

 casionally extended into brief rounded crests; commissural 

 ridges irregular in outline ; microspores fawn-colored, 35-42 \i 

 long, sometimes showing tendency toward winged condition. 



Distribution : Mexico. 



Specimens examined : 



Mexico: in grassy springy places near Guadalajara, State of 



