78 American Fern Journal 



stomates, 2-5 in. long. Sporangia broadly oblong, 

 mostly not spotted, with a narrow indusium. Mega- 

 spores .300 -.450 mm. in diameter, marked with minute 

 dots which rarely join to form wrinkles. Microspores 

 deep brown, .026 -.031 mm. long, spinulose or rarely 

 smooth. — Washington and Idaho to California, Colorado 

 and Utah. 



7a. Isoetes echinospora Braunii (Durieu) Engelm. 



Brawn's Quillwort. 



Plant submerged, or in dry seasons emersed. Leaves 

 10-30, usually 3-6 in. long, sometimes 10 in. long, without 

 peripheral bast-bundles, half-erect in water, recurved out 

 of water, dark green, occasionally reddish at base, bear- 

 ing stomates only at tip. Sporangium pale, spotted, 

 half-covered by the indusium. Megaspores .350-1550 

 mm. in diameter, covered with spinules; spinules wide, 

 often forked or toothed, sometimes recurved, often con- 

 fluent and incised at tips. Microspores .026 -.030 mm. 

 in length, white or gray, smooth, numerous. — Alaska to 

 Labrador and Greenland, south to Pennsylvania, Utah, 

 Washington. 



7b. Isoetes echinospora Flettii Eat. 



Differs from var. Braunii in having stout leaves; spines 

 of megaspores few, short, wart-like; microspores also 

 spinulose.— Washington and British Columbia. 



EQUISETACEAE. Horse-tail Family. 



rush 



branched; stems jointed, usually hollow, arising from 

 subterranean rootstocks; the sterile and fertile often 

 unlike, the epidermis containing silica. Sterile leaves 

 reduced to sheaths at joints; fertile leaves forming a 

 cone-like spike terminating the stem. Sporangia clus- 

 tered beneath the cone scales, each with 1 spore-hollow. 



