THE AQUATIC QUILLWORTS. 



Megaspore of 



Isoetes echinospora 



Flettii. 



appear to be trivial ones produced by tlie habitat in 

 which they grow. Most botanists now give little atten- 

 tion to them. According to Eaton Boottii is found in 

 sand, and this may account for its characteristic slender 

 leaves. 



Isoetes ecJiinospora mvricata is a more pronounced form. 

 The leaves are longer, slenderer, and 

 inclined to be spiral and the mega- 

 spores are slightly larger, and covered 

 with shorter, thicker, and more con- 

 fluent spinules. In deep water the 

 slender leaves are inclined to take on 

 a spiral form. This variety is found 

 from Nova Scotia to New Jersey. 

 Isoetes echinospora Flettii comes from a 

 few lakes in Washington and British 

 Columbia, and differs from the type in having stout 

 leaves, and the spines of the megaspores few, very short, 

 almost wart-like. This is an extreme form and by some 

 might be considered a distinct species. In spore char- 

 acters it approaches the various other species of the 

 Northwest, and except for the size of the spores might 

 be considered a variety of Isoetes Bolanderi. 



A stout plant, also from northwestern 

 America, has been named Isoetes echino- 

 spora truncata. This has megaspores 

 thickly covered with short truncate 

 columns. The spores are noticeably 

 flattened on the hemispheres contain- 

 ing the commissures, and are not 

 easily confused with those of other 

 species. This form is reported from Vancouver Island 

 to Alaska, but is as yet not common. The author would 



Megaspore of 

 Jsoetes irtntcatat 



