. Dansk botanisk arkiv. Plants; Plants -- Denmark. 242 Dansk Botanisk Arkiv, Bd. 3. Nr. 1. no indications as to the position of the tetrasporangia; J. Agaedh gives a very good and detailed description of it. Judging from that this species appears to be like a Ceramium diaphanum, regularly dichotomous and with isolated projecting tetrasporangia. However, when these organs are not present, this species is not easily recognizable. In referring the present specimens to Ceramium fastigiatum we have in view the shape and size of the tetrasporangia. As these, how- ever, do not seem to agree en- tirel
. Dansk botanisk arkiv. Plants; Plants -- Denmark. 242 Dansk Botanisk Arkiv, Bd. 3. Nr. 1. no indications as to the position of the tetrasporangia; J. Agaedh gives a very good and detailed description of it. Judging from that this species appears to be like a Ceramium diaphanum, regularly dichotomous and with isolated projecting tetrasporangia. However, when these organs are not present, this species is not easily recognizable. In referring the present specimens to Ceramium fastigiatum we have in view the shape and size of the tetrasporangia. As these, how- ever, do not seem to agree en- tirely with the typical form de- scribed by Harvey (Phyco- logia Britannica, pi. 255) it seems preferable to con- sider them as representing a special form: f. flaccida, so cal- led because their filaments are extremely thin and flabby. The tufts are 4—5 cm high, built up by dichoto- mous threads. The axial cells are about 400 /jl long, 50 // broad, with zones 30—40 /t high and 50 // broad, often only 20 fj. high. The zones do not increase in the margins; the upper marginal cells are often smaller than the other Fig. 231. Ceramium fastigiatum (Roth) „„„t-„„i ppii„ at^ alandular Harv. f. flaccida H. E. P. a, part of a cortical cells. IN O gianauiar young filament; fe, part of an older one; cells are present. The sum- c, zone ^^^h^^ te^^^lP'^p^^^^gjJ- (^^^"^ mits of the filaments are not very curved and the zones are here quite close together. The tetrasporangia are isolated and prominent. Sexual organs are not present. Of the specimens of C. fastigiatum distributed in Phycotheca , No. 446 the uppermost one of those belonging to the Botanical Museum, Copenhagen, agrees in some respects with the present form, especially as to the shape and size of the zones. The other specimen is a typical Ceramium strictum. Ceramium fastigiatum f. flaccida is found in sheltered locali- ties and in shallow water and grows upon the roots of the man- groves, to which it is fa
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