218 



Dansk Botanisk Arkiv, Bd. 3. Nr. 1. 



The antheridial stands (Fig. 203 E, F) are found at the same 

 places as the tetrasporangia; they consist of a system of closely 



placed, short branches, of which 

 each bears 2 — 4 antheridia. 



The cystocarps (Figs. 202, 

 203 G, 204) are binate and trilo- 

 bed heart-shaped, sometimes also 

 more irregularly formed. The 

 younger and smaller ones consist 

 only of a single layer of carpo- 

 spores (Fig. 203 K), but in the 

 bigger cystocarps and especially 

 in the more irregularly shaped 

 several layers are also present. 

 The carpogonial branch is 

 four-celled and possesses a very 

 long trichogyne (Fig. 203 /). 



The plant occurred as a com- 

 mon epiphyte on Gracilaria 

 Blodgetti and was found only 

 in deeper water (about 15 fat- 

 homs). It was collected \V\i\\ tetraspores, antheridia and cystocarps 

 in the month of March. 



Occurred in many places in the sound between St. Tliomas and St. 

 Jan: off Cruz Bay. 



Geogr. Distrib. : Hitherto found only in theabove mentioned locaUty. 



Fig. 204. Callithamnion cordatum 



Borgs. Branch with cystocarps and 



a single tetrasporangium (50:1). 



2. Callitbaranion byssoides Arn. 



Arnott in Hooker, English Flora, vol. II, part I, 1833, p. 342 (Algæ 

 by Harvey). Harvey, Manual, 1849, p. 178; Phycol. Brit, pi 262. Are- 

 scHouGH, I. E., Phyceae Scandin. Marinae, 1850, p. 107, pi. V, B. Cfr. 

 Schmitz, Fr., in Berichte d. deutsch, bot. Ges., Bd. XI, 1893, p. 280. Børge- 

 sen, F., Some new or little known West Indian Florideæ (Bot. Tidsskr., 

 vol. 30, 1909, p. 11). 



Regarding a comparison of the West Indian form with plants 

 from other countries I refer to my remarks, 1. c. Here I shall 

 restrict myself to give a short description only of the West In- 

 dian plant (Fig. 205). 



It has a rather vigorous main stem whose cells are about 

 3 — 4 times as long as broad (lat. cell. = 140//); higher up the 

 cells grow thinner and thinner, the youngest tips of the branches 

 being only 9 — 10// thick. The branches emerge spirally from the 



