. Dansk botanisk arkiv. Plants; Plants -- Denmark. F Børgesen: Rhodophyceæ of the Danish W. Indies. 247. Fig. 235. Laurencia Poitei (Lamour.) Howe. Transverse sec- tion of the peripheric tissue of the thallus. (About 150:1). a few cm in height, in somewhat more sheltered places it grows higher, up to 10 cm or even more. It is firmly fastened to the rocks by means of a broad and rather thick disc, from which several, and often many, erect branches grow up. Growing as it often does in the most exposed places, the thallus is of a very firm and cartilaginous con- sistency. The tissue of the plant
. Dansk botanisk arkiv. Plants; Plants -- Denmark. F Børgesen: Rhodophyceæ of the Danish W. Indies. 247. Fig. 235. Laurencia Poitei (Lamour.) Howe. Transverse sec- tion of the peripheric tissue of the thallus. (About 150:1). a few cm in height, in somewhat more sheltered places it grows higher, up to 10 cm or even more. It is firmly fastened to the rocks by means of a broad and rather thick disc, from which several, and often many, erect branches grow up. Growing as it often does in the most exposed places, the thallus is of a very firm and cartilaginous con- sistency. The tissue of the plant is also built quite according to its habitat. The epidermal cells, when seen from above, are small, roundish and have very thick walls; upon a transverse section they are found to be long and narrow like palissade cells (Fig. 236). They are about 25/i long and 8;/ broad. Also the cells in the interior of the thallus have thick walls. The central cylinder is not easily distinguishable. Only plants with tetraspores were found. These are formed in the summit of the wart- like ramuli. It is a common plant along the more open Fig. 236. Laurenciapa- parts of the coast of the islands. pillosa (Forsk.) Grev Geogr. Distrib.: Warmer parts of the At- 1 rcinsv6rs6 S6Ction oi nr t n t^jo c* a peripheric part of lantic Ocean, Mediterranean Sea, Ked bea, bana- thallus. (About 200:1V wich Islands etc. mwm 3. Laurencia obtusa (Huds.) Lamour. Lamouroux, J. V. F., Essai in Annales du Museum d'Hist. Nat., vol. 20, 1813, p. 130. J. Agardh, Spec. Alg., vol. II, p. 3, p. 750; Epicrisis, p. 653. Harvey. Phycologia Brit., pi. 148. Fucus obtusus Huds. Fl. Angl., p. 586. Turner, D., Fuci, vol. I, tab. 21. The specimens I refer to this species are very heterogeneous, and it may be that several different forms have been classified together. What especially characterizes this species is that the rami- fication has more or less a tendency to be verticillate; this being especially the case in the var. gelat
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