1922] 



PFEIFFER MONOGRAPH OF THE ISOETACEAE 207 



Missouri: ponds in the Meramec Hills, southwest of St. Louis 

 (Gravois Settlement), September, 1842, Engelmann (Mo. 

 Bot. Gard. Herb, and Gray Herb.), TYPE; St. Louis, Sep- 

 tember, 1842, Engelmann (U. S. Nat. Herb.). 



58a. Var. caroliniana Eaton, Fern Bull. 8 : 60. 1900. 



Corm 2-lobed; leaves 15-25(30), up to 22 cm. long, little 

 finer than /. Engelmanni (much like /. Dodgei] ; peripheral 

 strands 4, weak; stomata numerous; sporangium 6-8 mm. long, 

 1/3-2/3 covered by velum ; megaspores 400-530 \\ in diameter, 

 with high reticulate ridges, much crisped and cut with an ir- 

 regular margin, producing somewha^' spiny effect; microspores 

 24-34 (j long, spinulose. 



Distribution: North Carolina, Georgia. 

 Specimens examined: 



North Carolina: Big Rock Creek, Mitchell Co., 1893, Ashe 1092 

 (Mo. Bot. Gard. Herb.), TYPE; growing partly immersed, 

 Wetherby's near Salisbury, Mitchell Co., Ashe 812 (Mo. 

 Bot. Gard. Herb.) ; Roandale Farm, 28 July, 1900, Wether- 

 by (Mo. Bot. Gard. Herb.) ; edge of fish-pond, gravelly bot- 

 tom, half submerged or less, Wetherby's, 15 August, 1898, 

 Wetherby (Mo. Bot. Gard. Herb.). 



Georgia: muddy swamp of Turkey Creek, about 6 mi. south of 

 Dublin, Laurens Co., 21 April, 1904, Harper 2142 (U. S. Nat. 

 Herb.) ; in sluggish pine-barren stream, Sumter Co., partly 

 emersed, 24 July, 1901, Harper 1112 (Mo. Bot. Gard. Herb, 

 and U. S. Nat. Herb.). 



59. I. azorica Dur. Milde, Fil. Eur. 278. 1867; Baker, Jour. 

 Bot. 18: 67. 1880, and Fern Allies, 125. 1887; Motel. & Vendr. 

 Actes Soc. Linn. Bord. 36: 365. pi. 8. jig. 9, 10, 11. 1883; Trelease, 

 Mo. Bot. Gard. Ann. Rept. 8: 176 . 1897. 



Calamaria azorica Kuntze, Rev. Gen. PI. 2 : 828. 1891-93. 



Corm 2-lobed; leaves 7-25, 8-30 cm. long, slender, flexuous, 

 with narrow basal membranaceous margin ; stomata present, but 

 not numerous; peripheral strands none; ligule long subulate; 

 sporangia oval, 4-6 mm. long, 1/3-1/2 covered by velum ; mega- 

 spores 360-490 M in diameter, white, reticulate with narrow low 

 distinct crests, mostly rounded, seldom sharp; microspores 



