The Life History of Griffithsia Bornetiana . 1 
BY 
I. F. LEWIS. 
With Plates XLIX-LIII, and two Figures in the Text. 
HE red alga, Griffithsia Bornetiana , was first described by W. G. 
X Farlow (28). It has been reported as occurring commonly from 
northern Massachusetts (Collins, 18, p. 50) south to Long Island Sound, 
and has been recorded from New Jersey (Britton, 13). 2 It forms rosy tufts 
of branching filaments (PI. XLIX, Fig. 1), 2*5 to 15 centimetres high, on rocks, 
‘ wharves, sponges, shells, and occasionally on Zostera ’ (Farlow, 29, p. 131). 
South of Cape Cod it is found growing from one to four feet below low 
water mark, in protected situations such as the Little Harbor at Wood’s 
Hole, Mass., and on rocks in more exposed localities. 
The present investigation was begun in 1905 on material collected 
at Cold Spring Harbor, New York, by D. S. Johnson in 1902, and has been 
continued during 1906 and 1907 at Wood’s Hole and at the Johns Hopkins 
University. 
In all plants examined, with two exceptions noted below, the antheridia 
cystocarps, and tetraspores are borne on separate individuals, which may be 
readily distinguished with the aid of a hand lens. The male plant is smaller 
and more compact than either the female or tetrasporic plant, and may be 
identified by the abrupt terminations of the filaments (Fig. 2). It rarely 
becomes more than 4 centimetres high. The female plant is more loosely 
tufted than the male, and reaches a much larger size* becoming 12 to 
15 centimetres high. The cystocarps form deep red dots at the sides 
of the nodes (Fig. 3). The filaments of the female plant do not end 
abruptly, but become gradually smaller toward their tips. The tetrasporic 
plant is more slender than the female, and to the eye more nearly like 
it than the male. It may be distinguished by the whorls of tetraspores, 
which form complete rings at the nodes (Fig. 4). The tetrasporic plant, 
1 Contribution from the Botanical Laboratory of the Johns Hopkins University, No. 9. 
2 The form reported from as far south as the Barbadoes by Mile. Vickers (86) is believed by 
Dr. Farlow not to be identical with G. Bornetiana. 
[Annals of Botany, Vol. XXIII. No. XCII. October, 1909.3 
