Other species of a gelatinous nature, like Nemalion and Dudresnaya, may be allowed to dry on the paper, and need not be submitted to pressure until they no longer present a gelatinous appearance.
Unknown in Cyanophyceae and Phoeophyceae, known only in Bangiaceae and Nemalion among Rhodophyceae, they are of frequent occurrence among Chlorophyceae, excepting Characeae.
This fusion has been observed by Wille in Nemalion multifidim, and by Schmidle in Batrachospermum.
In Batrachospermum filaments arise from the carpogonium on all sides; in Chantransia and Scinaia on one side only; in Helminthora the filaments are enclosed in a dense mucilage; in Nemalion, prior to the formation of the filaments, a sterile segment is cut off below.
Nemalion sp., carpogonial and antheridial branches.
The genus Nemalion has been recently investigated by Wolfe with the object of examining the cytological evidence.
Upon the evidence it would seem therefore that so far as Nemalion is concerned an alternation occurs comparable with that existing in the lower Bryophyta where the sporophyte is relatively small, being attached to and to some extent parasitic upon the gametophyte.
Nemalion is, however, one of those Florideae in which tetraspores do not occur.
The whip-forms are represented by Spirogyra, Chaetomorpha, Scytosiphon, Nemalion, Himanthalia and Chorda.
Compare, for example, the blue-green Gloeocapsa with the green Gloeocystis, the red Batrachospermum with the green Draparnaldia, the red Corallina with the green Cymopolia, the green Enteromorpha with the brown Asperococcus, the green Ulva with the red Porphyra, the red Nemalion with the brown Castagnea, and so on.
Wille, " Uber die Befruchtung bei Nemalion multifidum," Ber.
Wolfe, " Cytological Studies on Nemalion," Annals of Botany (vol.