VALONIACE^. 45 



less compressed, erect, coated with a velvetty scurf, and partially incrusted with cal- 

 careous matter ; nearly destitute of lime when young, much incrusted with it in old 

 age. This stipes is composed of innumerable, densely packed, longitudinal, unicellular 

 fibres which closely adhere by lateral branching processes, and are interlaced together. 

 The outer strata of these fibres emit, to form the periphery of the stipe, innumerable 

 short, lateral, horizontal, multifid, fastigiate ramelli, whose apices, lying close together, 

 give the velvetty appearance to the surface. As long as these longitudinal filaments 

 cohere into a stipe they are unicellular ; but when they become free at the apex of the 

 stipe, they are articulated, or pluricellular ; and a capitidum of confervoid filaments 

 comjiletes the frond. According to the age of the specimen, the filaments of the 

 capitulum are more or less developed ; in young specimens they are less than an inch 

 long ; in older and full-grown ones they vary from 3 to 6 inches. They are densely, 

 but not intricately tufted, thicker than hog's bristle, dichotomous, radiating to all 

 sides, equal and obtuse ; their articulations are cylindrical, and many times longer than 

 broad. The colour is a full, deep green, and they are very thinly incrusted with lime ; 

 the crust pierced with minute pores. The primordial utricle separates readily from the 

 cell-wall, and is firmly membranous. 



Plate XLIIL A, Fig. 1, 2, 3. Penicillus dumetosus, of difierent ages : the 

 natural sizes. Fig. 4. Portion of one of the dichotomous filaments of the capitulum. 

 Fig. 5. Small portions of the same, after the calcareous coating has been removed, 

 showing a pitted surface ; the latter figures more or less highly mngnijied. 



2. Penicillus capitatus, Lamk. ; stipes long or short, cylindrical or clavate, terete, 

 incrusted, smooth ; filaments of the globose capitidum densely crowded, fastigiate, 

 capillary, rigid, pale green, their joints cylindrical, many times as long as broad, 

 obtuse, constricted at the nodes. Due. Cor. p. 97. Nescea Penicillus., Lamour. Pol. 

 fiex. p. 2.58. Corallina Penicillus, Ell. and Sol. p. 126, tab. 25, Jig. 4, 5. Corallo- 

 cephaliis Penicillus, Kiitz. Sp. Alg. p. 505. (Tab. XLIII. B.) 



Hab. Key West, W. H. H., Prof. Tuomey. (v. v.) 



Root very large, two inches long or more, deeply descending, very fibrous and 

 densely matted. Stipes from one to four or five inches long, a quarter to a third of 

 an inch in diameter, mostly cylindrical and equal throughout, occasionally compressed 

 and widened upwards, thickly incrusted with calcareous matter, and having a smooth 

 and sometimes a polished surface. Capitulum very dense, mostly globose, sometimes 

 oblong and rarely somewhat difi'use, fiistigiate, one or two inches in diameter, composed 

 of innumerable, curved, densely packed and often entangled, capillary filaments which 

 are encrusted with calcareouis matter to an extent that makes them rigid. The 

 structure is similar to that of the preceding species ; and the calcareous incrustation 

 is similarly dotted or pitted. The length of the articulations varies much ; usually 



