5 2 



ISOETACEAE. 



Vol. I. 



5. Isoetes saccharata Engelm. Sugary Quill- 

 wort. Fig. 122. 



Isoetes saccharata Engelm. in A. Gray, Man. Ed. 5, 676. 



1867. 



Amphibious or uliginous with a flat depressed trunk. 

 Leaves' 10-30, green, pale at the base, spreading, 2-3' 

 long, quadrangular, bearing numerous stomata ; 

 sporange oblong, unspotted, with a narrow velum 

 covering only one-fourth or one-third of its surface; 

 peripheral bast-bundles wanting; ligule triangular, 

 rather short; macrospores 420-510 m in diameter, with 

 very minute distinct or rarely confluent warts as if 

 sprinkled with grains of sugar; microspores sparingly 

 papillose, 22-30 M long. 



In mud overflowed by the tides, eastern Maryland 

 and District of Columbia. 



6. Isoetes riparia Engelm. Riverbank 

 Quillwort. Fig. 123. 



Isoetes riparia Engelm.; A. Br. Flora, 29: 178. 1846. 



Amphibious or uliginous, usually emersed when 

 mature; leaves 10-30, green, rather rigid, 4'-8' 

 long, quadrangular, bearing numerous stomata ; 

 peripheral bast-bundles wanting; ligule rather 

 short, triangular; sporange mostly oblong, dis- 

 tinctly spotted with groups of brown cells, one- 

 fourth to three-fourths covered with the velum; 

 macrospores 450-756 f- in diameter, marked with 

 distinct or anastomosing jagged crests or some- 

 what reticulate on the lower side; microspores 

 28-32 n long, more or less tuberculate. 



Borders of the lower Delaware River. 



7. Isoetes foveolata A. A. Eaton. Pitted Quillwort. Fig. 124. 



Isoetes foveolata A. A. Eaton ; Dodge, Ferns 

 and Fern Allies of New Eng. 38. 1896. 



Isoetes foveolata pleurospora A, A. Eaton, 

 Rhodora 5: 280. 1903, 



Amphibious from a bilobed or rarely 

 trilobed base. Leaves 15-70, stout, 2'-6' 

 long, pinkish even when dry, or rarely 

 dark green; stomata scattered, found only 

 near the tips; no peripheral bast-bundles; 

 monoicous or becoming dioicous ; velum 

 covering 1 or 5 of the sporange ; ligule 

 round-ovate; sporanges thickly sprinkled 

 with dark cells which are often collected 

 in groups ; macrospores 380-560 A*, covered 

 beneath with very thick-walled reticulations, 

 the openings appearing like little pits; re- 

 ticulations elongate on the upper surface 

 of the spore ; microspores dark brown, 

 22_ 3S v- long, densely reticulate and usually 

 slightly papillose. 



In muddy banks, New Hampshire, Massa- 

 chusetts and Connecticut. 



