230 CERAMIACEiE. v. 



specimen is well or ill dried. For the convenience of easy reference, I divide tte 

 American species into the following six sections : — 



Sect. 1. Fruticosa : Frond shrub-like^ the stem and branches more or less filled with 

 veins, imperfectly articulate. Eamuli pectinate or pinnate, the pinnm alternate or 



secund. 



1. Callithamnion Pikeanum ; frond robust, fruticose, with an undivided, opaque 

 stem, set with alternate, similar branches directed to every side ; branches alter- 

 nately decompound, opaque, the lesser divisions densely beset on all sides with 

 minute, imbricated, articulated ramuli ; ramuli divaricate, pectinate or bi-pectinate 

 on the outer side (the naked side directed to the rachis), the ultimate divisions 

 spreading at right angles, subulate, sub-acute ; articulations of the ramuli once and 

 half as long as broad ; tetraspores tri-partite, sessile, one or more together on the 

 ultimate ramuli. 



Hab. Golden Gate, California, Capt. Nicholas Pike. (v. s. in Herb. T. C. D.) 



Frond solitary ? Stem four to five inches high, half a line in diameter at the base, 

 undivided, slightly attenuated upwards, opaque, set with similar, opaque, alternate 

 branches, which again bear a second or third series of similar, but smaller branches. 

 Branches directed to every side, the larger ones either naked or clothed with 

 minute, haii'-like ramuli, the lesser ones very densely set on all sides with minute, 

 multifid ramuli, one to two lines in length. These ramuli alone are pellucidly 

 articulate, the articulations once or twice as long as broad. They are set at right 

 angles to the branches from which they spring, but are curved or arched inwards, 

 so as to present to the branch the concave face, which is bare of ramelli ; the convex 

 or outward face being pectinated with horizontally patent or divaricated, spine-like, 

 simple or again pectinellated ramelli. Tetraspores roundish, triangularly-parted, 

 sessile, or borne on the ultimate divisions of the ramuli. Favellw I have not seen. 

 The colour is a dark, vinous purple. The substance is firm and rather rigid. It 

 imperfectly adheres to paper in drying. 



This species is very different from any American one known to me, but is nearly 

 related to the European C. Arbuscula, and still more closely to the South African 

 C. purpuriferum, J. Ag. ; but appears to be distinct from both. It is a stronger 

 growing plant than C. Arbicscula, with more squarrose and thicker ramuli. From 

 C. purpuriferum it differs in colour, in the ramification of the ultimate ramuli, in 

 the much greater opacity of the stem and branches, the structure of the tetraspores, 

 &c. I have pleasure in bestowing on it the name of Captain Nicholas Pike, of 

 Brooklyn, an ardent student of marine plants, to whom I am indebted for a very 

 interesting collection of Californian Alga3, among which was this species. 



2. Callithamnion tetragonum, Ag.; frond ultra-setaceous, shrub-like, with a per- 



