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PACIFIC SCIENCE, Vol. XV, January 1961 
Figs. 20—24. Cellular reproductive and vegetative peculiarities of Helminthocladia rhizoidea. 20, A cortical 
heterofilamentous system, wherein some branches are of slender long cells (v) and some terminated by "normal” 
obpyriform cells, normal (e.g., cp) and seemingly abnormal carpogonial branches. 21, Cellular details of a 
cortical vegetative system illustrating a hair base (h), slender cortical filaments (/), and two of the rhizoids 
(f) which characteristically issue from the assimilatory region. 22, Origin of a rhizoid (r) from an assimila- 
tory cortical filament, a well-developed gonimoblast (lightly stippled) with three hypogynous cells (darkly 
stippled) and several small-celled involucral filaments (/). 23, One of the rhizoids (r) peculiar to this species 
and well-formed carpogonial branch (cp). 24, A young gonimoblast with two one-celled encircling rhizoids (r) 
developed from supra-supporting cells, and a slender cortical filament (/). 
characters of this kind are necessary aids to dis- 
tinguishing the ever growing number of species 
in this genus. 
The sterile filaments surrounding the cysto- 
carp of H. rhizoidea (Fig. 22^') appear to re- 
semble closely those in H. papenfussii as illus- 
trated by Martin (1939), although the deriva- 
tion of the sterile filaments may not be the same 
in both species. Martin states that the sterile 
filaments arise from the vegetative cell above the 
supporting cell in H. papenfussii. This is true 
also in H. australis ( Desikachary, 1957&) where, 
however, they may also arise from the cell below 
the supporting cell. The derivation in H. rhizoi - 
dea also may be from above or below the sup- 
porting cell. 
The possession of a loose basket of sterile 
filaments around the gonimoblast in H. rhizoi- 
dea seems to furnish a further characteristic for 
distinguishing this species from H. simplex. 
Only the initial few cells of the involucre are 
illustrated in Figures 22 and 24 for H. rhizoidea , 
while perhaps the ultimate in development of 
rhizoids is given in Figures 6, 7, 9, 11, 14, 15 
for H. simplex. 
Most species of Helminthocladia appear to 
have fairly regularly dichotomous assimilatory 
filaments; see the illustrations of H. calvadosii 
(Kylin, 1930), hi. hudsoni (Feldmann, 1939), 
H. australis (Desikachary, 1957&), and those 
of H. simplex , especially Fig. 18 in this paper. 
In this respect H. papenfussii and the present 
