122 ' Rhodora • [J^tly 



In addition to these forms which considerable field study of their 

 habit and surroundings have shown to be unmistakably of hybrid 

 origin and in which, for the most part, it has been easy to determine 

 from what species they have been derived, there are many uncertain 

 forms in need of further study. Among them may be noted what 

 seems to be a triple hybrid between T/o/a {fimhriaiuJa X papili(>nacea) 

 and Viola emarginata, at Takoma Park, July 23, 1904 (No. 95). 



Clemson College, South Carolina. 



Explanation of Plates. 



Plate 71. Viola Brittoniana X emarginata House. (Natural size.) a. 

 Flowering plant, b. Mature leaf. c. Cleistogainous flowers, d, e. Capsules 

 from cleistogamous flowers. 



Plate 72. Viola Stoneana X villosa House. (Natural size.) a. Flowering 

 plant, b. Mature plant, c. Cleistogamous flower, d. Capsule from cleisto- 

 gamous flower. 



NOTES ON ALGAE,— VII. 



F. S. Collins. 



In this number of the Notes are included records of various species, 

 etc., new to our flora; also a few items of interest in regard to previously 

 recorded species; unless otherwise indicated, all were collected by the 

 writer. 



Phormidium Retzii (Ag.) Gomont forma fasciculatum (Br6b.) 

 Gomont, Monogr. des Oscill., p. 197. The typical P. Retzii is a 

 widely distributed species, and is common in sluggish waters through- 

 out New England, in the form of rather firm coatings, from one half 

 to one cm. thick, on stones and other objects. When the current is 

 rather brisk, these coatings sometimes fringe out into narrow strings, 

 but the extreme form appears to be unusual. It Avas found by the 

 writer in quite rapid water, in Lynnfield, Mass., June 11, 1905. There 

 was a distinct stipe-like part, flattened, expanding above into a broader 

 lamina, repeatedly dividing, and ending in innumerable long, slender, 



