■9°9l 



* STOKEY— ANATOMY OF ISOETES 3*3 



rability of a comparative study of several species embracing a 



considerable range of habit is obvious. 



Material 



material of I. Tucker mani var. H 



Ha 



Maine 



cf development ; to Mr. Wilhelm Suksdorf for material ol 

 /. Nuttallii Engelm. (7. Suksdorfii Baker) collected at Bmgcn, 

 Wash.; and to Dr. H. C. Cowles for material of I. 



echinosp 



rieitu which he collected at bpanaway i^aK.c, w^..., ^ -~ 

 of 1907. The latter material has been kept in cultivation at the 

 greenhouses of the University of Chicago and has afforded abundant 

 material for ihe study of a close series of stages in the development ol 

 the stem. I am also indebted to the late Mr. A. A. Eaton of me 



Mass 



tion of I. melanopoda 



For killing and fixing the stems a medium solution of chrom-acetic 

 acid was used. The material was embedded in paraffin and cut in 

 rial sections 7 to 12 /* thick. Some of the series were transverse 

 and others longitudinal, both parallel and perpendicular to the iur- 

 «w. A considerable number of stains and combinations of stains 

 *ere used, of which the most satisfactory were the following: a com- 

 bination of safranin and anilin blue devised by Dr. Land; 10 1 

 green and Bismarck brown ; iodin green and eosin. _ 



The four species studied present a considerable range in ia 1 . 

 '• Tukermani var. Harvey i is a submersed form which grows in 

 water 30-1 ,„« dee p. The trunk is deeply two-lobed, occasiona l 

 ^ree-lobed. The leaves are short, strongly recurved, without 

 st °mata, and said bv Eaton (8) to be relatively the stoutest otji ^ 



^rth American species, being 5 ^ cm ™ len § th and 'j^avellv 

 ^"icter. hoetes echinospora var. Flettii grows on the n ra 

 %s of mountain lakes in Washington. In the spring it ma> 

 ^bmersed, but during most of the year it is out of the water, 

 ^l holds water so that the substratum is never very dn . 



*»* is two-lobed and the leaves are moderately stout. The ^ 

 form stn^j • r . . , T , 1 i„„„» two-lobed trunk, vim 



m studied is J. melanopoda 



r> 



