A SYNOPSIS OF THE SPECIES OF ISOETES. 69 



parallel anastomosing ridges, the lower half reticulated. Micro- 

 spores nearly or quite smooth. 



Hab. Ponds near Boston, associated with forms of echinospora, 



Tuckerman ! 



» 



12. I. saccharata, Engelm. in Gray Man., edit, v., 676. 



Rootstock 2-lobed. Leaves 10-15, 2-3 in. long, slender, 

 diaphanous, olive-green, furnished with stomata, but without 

 accessory bast-bundles. Sporange small, ovoid, nearly unspotted, 

 only the upper edge covered by the veil. Macrospores middle- 

 sized, minutely tubercled. Microspores papillose. 



Hab. On "Wicomico River, eastern shore of Maryland, between 



high and low tide, Canby. 



13. I. riparia, Engelm. in Gray Man., edit, v., 676. — Eoot- 

 stock 2-lobed. Leaves 15-30, resembling those of lacmtris in size 

 and texture, 4-8 in. long, J-£ lin. diam. at the middle, deep green, 

 diaphanous, furnished with stomata, but without accessory bast- 

 bundles. Sporange oblong, spotted, -J- in. long; veil partial. 

 Macrospores middle-sized, white, strongly granulated all over. 

 Microspores large, tubercled. 



Hab. Gravelly banks of the Delaware, and margin of ponds in 

 New England. 



14. I. melanospora, Engelm. in Oaks United States, ii., 

 in note. — A dwarf gregarious, usually monoicous species, with 

 a 2-lobed rootstock. Leaves few, slender, distichous, fur- 

 nished with stomata, but without accessory bast-bundles. 

 Sporange small, globose ; veil complete. Macrospores minute, 



sometimes blackish, obscurely granulated. Microspores obscurely 

 papillose. 



Hab. Georgia, on Stone Mountain, in shallow depressions of 

 the base granite rocks near the summit, Canby. Discovered 

 m 1869. 



15. I. Muelleri, A. Br. in Berl. Monatber., 1868, 541 . — Rhizome 

 3-lobed. Habit of I. echinospora. Leaves about 3 in. long, pale 

 green, diaphanous, narrowed to the point, furnished with stomata, 

 but without accessory bast-bundles. Sporange globose; veil com- 

 plete. Macrospores with numerous minute unequal tubercles 

 confluent into ridges. 



Hab. Queensland, in ponds at Rockhampton, CyShanessey. 

 Discovered in 1867. 



ans 



I. Kirkii, A. Br. in Berl. Monatber., July 22, 1869; Kirk in 

 New Zeal. Instit., ii. 107, t. 7.— Rootstock 3-lobed. Habit 

 °i slender forms of I. echinospora, Leaves 10-20, 3-4 in. long, 

 2 lin. diam. at the middle, pale bright green, diaphanous, tapering 

 jo the point, furnished with a few stomata, but without accessory 

 bast-bundles. Sporange small, globose; veil complete. Macro- 

 spores small, beset all over with minute unequal tubercles. 



Hab. New Zealand, in lakes at a low level in the northern 

 island, Kirk ! 



