. Dansk botanisk arkiv. Plants; Plants -- Denmark. F. Børgesen: List of species. 469 131. Digeiiea simplex (Wulf.) Ag. In a collection consisting of various algæ I have come across the male plant of this species. The antheridial stands have pre- viously been known only from a figure in Kützing's "Tabulæ Phycologicæ", vol. 15, pi. 28, fig. m. Concerning this figure Fal- kenberg in his monograph of the Rhodomelaceæ writes p. 160: "Die Antheridien habe ich zwar nicht selbst gesehen, aber die Abbildung Kützing's lässt wohl kaum eine andere Deutung zu, als dass es sich bei Di
. Dansk botanisk arkiv. Plants; Plants -- Denmark. F. Børgesen: List of species. 469 131. Digeiiea simplex (Wulf.) Ag. In a collection consisting of various algæ I have come across the male plant of this species. The antheridial stands have pre- viously been known only from a figure in Kützing's "Tabulæ Phycologicæ", vol. 15, pi. 28, fig. m. Concerning this figure Fal- kenberg in his monograph of the Rhodomelaceæ writes p. 160: "Die Antheridien habe ich zwar nicht selbst gesehen, aber die Abbildung Kützing's lässt wohl kaum eine andere Deutung zu, als dass es sich bei Digenia in der That um flache, ovale Anthe- ridien handelt, die am oberen Ende der Sprosse gehäuft stehen. Ich wäre eher geneigt, die Abbildung auf misverstandene eingekrümmte Blätter zu deuten, wenn ich nicht bei Bryothamnion analoge flache Anthe- ridien gefunden hätte". The male plants recently discovered by ^^ ^^â J.\%:'iZ- me prove that Kützing has had such a mit of the thallus with plant at his disposal. The antheridial stands '"'^About^'sivn"^'" are, when fully developed, discoid bodies of obhque reniform shape; their entire surface is covered by the antheridia. A whole trichoblast is used to the formation of the antheri- dial stand just as in the case of Bryothamnion according to Fal- kenberg's description (1. c, p. 175), and its development takes place in a very similar way. From an apical cell with two sides seg- ments are cut off alternately at both sides. These segments or branches remain together, increasing gradually in length and at the same time dividing into smaller cells; and this process is carried on until the above mentioned flat bodies are formed. The antheridial plant was found in the month of January in shallow water near the shore. St. Croix: Lt. Princess. 132. Bryothamnion triquetrum (Gmel.) Howe. 133. â Seaforthii (Turn.) Kiitz. 134. Herposiphonia secunda (Ag.) Falkenb. As pointed out in my previous
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