might have passed as a grass patch. When growing so thickly 

 the trunks were small, but when more scattered they sometimes 

 attain a size of 1% inches, with 75 leaves, 18 inches long. These 

 leaves under water ascend spirally, fall flat and decay on subsi- 

 dence of water, and a new growth appears, shorter, tortuous and 

 often intricately interlaced in a manner not heretofore noticed in 

 any Isoetes. 



I made several trips to the locality in '96 and observed it in 

 all its phases. In '97 the water was not drawn off till the middle 

 of September, so the immersed form was rarely observed, but it 

 was characteristic so far as noticed. Inasmuch as the terms ver- 

 nal and aestival as applied to the leaves imply a dependence on the 

 season, while the forms depend entirely on the water, long when 

 submersed, short when growing on the bank after the water has 

 been drawn off, I abandon them and use the terms " submersed " 

 and *'emersed" leaves respectively, which terms are sufficiently 

 self-explanatory. 



Isoetes Dodgei, n. sp. Trunk, bilobed, .4~3 cm in. ) in 



diameter; /eaves, 10-75, submersed 2o-45 cm - (8-18 in. ) long, erect 

 when plants are close set, spirally ascending when scattered, 

 mostly female; emersed, stouter, 2 -3 mm - {1-1%, in.) in diame- 

 ter, io-i5 cm - (4-6 in.) long, tortuous and intricately interlaced, 

 mostly male, both with many stomata and usually 4 bast-bundles. 

 Ligula 2 mm - (1" in.) long, sharply lance-triangular; velum, 

 indusiate; sporangia, thickly sprinkled with light-brown cells. 

 Macrospores, globular, 500-675 //, averaging 560 \i in diameter, 

 sparsely covered with irregular crests, set on a reticulate pattern, 

 especially on young spores. As the spores develop, the crests 

 separate into irregular or isolated groups, with large bare spaces 

 between, or rarely they extend across one face of the spore. They 

 are always serrate or spinulose-rosulate at the top. Microspores, 

 ashy, 22-40//, average 32 /x, papillose. 



This belongs next I. riparia, from which it differs in its larger 

 size, longer leaves, narrower vellum, more isolated and jagged 

 sculpture of the macrospores, larger microspores, narrower dis- 

 sepiments to the leaves, as, indeed, the whole interior structure is 

 different; and especially in the bast bundles, which are nearly al- 

 ways present. At one time I thought it might be I. riparia var. 

 Canadensis Eng., and had it compared with specimens at the 

 Missouri Botanical Gardens, through the courtesy of Dr. Trelease. 

 As they differ in so many points no doubt of their being distinct 

 can be entertained. 



