THE 
HEW PHYTOhOGIST. 
Vol. XVII, No. 10. December, 1918. 
[Published January 9th, 1919.] 
DEVELOPMENTAL FORMS OF MARINE ALGAE. 
By Lilian Lyle. 
(With Plates I. and II. and Ten Figures in the Text.) 
O F the various points of view from which Marine Algae may 
be regarded, their plasticity of form, and response to 
changes in surrounding conditions afford peculiar interest and 
have attracted considerable attention. 
The dimorphism of Nitophyllum ramosum Batt. (Nit. lacerntum 
Grev.) is a case in point. At times the normally erect thallus takes 
on a procumbent position. The resemblance to Nitophyllum 
reptans is then so close as to lead one to suspect that the two 
species may be identical. 
The species Nitophyllum reptans has been described by 
Crouan * 1 and Zanardini 2 , but as shown in the following 
notes, the plant is really a prostrate stage of N. ramosum, and is 
accordingly removed to that species. 
The note on Recrudescence is tentative, referring to certain 
growth forms and their possible origin, such as changes in tissue 
substance, mechanical irritation, etc. 
1 have to express my sincere thanks to Miss Lorrain Smith 
and Mr. Gepp, both of the British Museum (Nat. Hist.), for their 
valued suggestions. 
Nitophyllum ramosum (Nit. laceratum Grev.) f. reptans. comb, 
nov. (Nitophyllum reptans Crn.), Figs. 1-13. 
After carefully examining a series of specimens of Nitophyllum 
reptans Crn. and Nitophyllum ramosum Batt. I have come to the 
conclusion that they belong to the same species, and that N. 
reptans is an occasional, prostrate and dorsiventral form of N. 
1 Crouan. Flore de Finisterre, p. 153. 
1851. Ann. Sci. Nat., T. xv, Ser. Ill, Gen. 146, p. 365. 
2 Zanardini. Icon. Phyc. Adriat., Vol. Ill, p. 85. 
