r. CRYPTOXEMIACE^. I95 



beset, in its upper half, with quasi-proliferous ramenta, given off without order and 

 often very densely fascicled, one to two inches long, filiform, simple or slightly ra- 

 mulose, sometimes forked, and very often twisted or otherwise distorted, all tapering 

 to the base, and in a less degree to the apex. Colour, a dark lurid purple, paler in 

 the ramenta. Substance rigidly membranaceous or sub-coriaceous. In drying under 

 pressure, it imperfectly adheres to paper. 



A most variable plant in the number and disposition of its ramenta, but easily 

 recognised after it has once been seen. 



Plate XXIX. A. Fig. 1, Halosaccion ramentaceum ; the natural size. Fig. 2, 

 transverse section of the frond ; magnified. Fig. 3, a small part of the same, more 

 highly magnified. 



XIX. FURCELLARIA. Lainour. 



Frond terete, dichotomous, fastigiate, solid, composed of three strata of cells ; 

 the medullary stratum of densely interwoven, longitudinal, elongate filaments ; 

 the intermediate of large, roundish cells ; the cortical of small cellules strung 

 together in moniliform, vertical filaments. Fruit of both kinds contained in the 

 swollen, pod-like apices of the branches. Nuclei {favellas) simple, immersed, formed 

 from some of the cells of the intermediate stratum, numerous in each pod, at length 

 often confluent, each containing many large angular spores in a cluster. Tetra- 

 spores immersed within the cortical layer, formed in its filaments, large, pear- 

 shaped, transversely zoned. 



Very similar in external aspect, and even in the internal structure of the frond, 

 to Polyides rotundus, a plant from which it differs so remarkably in fructification, 

 that in a classification founded on differences of fruit, we are compelled to place these 

 genera at opposite ends of our arrangement. The only known species, described 

 below, is common to a wide extent of the Northern Atlantic Ocean. 



1. FuRCELLARiA/as^^^iata, Lyngh.—J. Ag. Sp. Alg. 2, p. 196. Kut:. Sp. Alg. p. 

 749. Harv. Phijc. Brit. t. 94 and i. 358. Fucus lumbriealis, Turn. Hist. t. 6. F. 

 Bot. t. 846. 



Has. Newfoundland, Agardh. (v. v.) 



Root, a mat of creeping fibres. Fronds 4—8 inches high, nearly a line in diameter, 

 tufted, cylindrical, repeatedly dichotomous, the branches of equal height, the axils 

 and apices acute. When in fruit, the ends of the branches, for an inch or more, 



c c 2 



