240 CERAMIACE.E. 



V. 



articulations of the stem six to eight or ten times as long as broad ; upper much 

 shorter, and those near the ends of the branches but twice or thrice as long as 

 broad. The articulations of the rarauli are very short. Tetraspores numerous 

 on the pinna3 of the ramuli, sessile, cruciate. Favelloe unknown. Colour a fine 

 crimson. 



This plant has the external aspect of Cal. floccosum, but is more robust, and is 

 readily distinguished by its compound ramuli. It is more closely related to C. 

 Americajium, but the ramuli are shorter and more densely branched, with much 

 shorter internodes. The differences between these species may more readily be 

 understood, by comparing the figures we have given than by a detailed description. 



Until the favelte of this plant be discovered, some doubt may rest upon its gene- 

 ric position, yet I cannot but think it more nearly related to C. Americanum and 

 C. Jloccosum, between which it is nearly intermediate in character, than to Wrange- 

 lia midtifi.da, with which Professor Agardh associates it. 



Plate XXXVI. B. Fig. 1. Callithamnion Pylaiscei ; the natural size. Fig. 2, por- 

 tion of a branching stem, magnijied. Fig. 3, internode of a branch, with opposite, 

 bi-pinnate, fertile ramuli ; jig. 4, pinnule from the same, with tetraspores ; more 

 highly magnijied. 



14. Callithamnion jloccosum., Ag. ; frond capillary, very flaccid, remotely much 

 branched ; branches alternate, erecto-patent, articulated ; every node emitting a 

 pair of opposite, simple, subulate, erecto-patent, minute, ramuli ; tetraspores 

 elliptical, pedicellate on the ramuli near the base. J, Ag. Sp. Alg. 2, p. 27. 

 Harv. Phrjc. Brit. t. 81. Iviitz. Sp. Alg. p. 64G. 



Hab. South Boston, very rare, Dr. Durkee. (v. s. in Herb. T. C. D.) 



Filaments capillary, four to six inches long, alternately or sub-dichotomously 

 branched, the lower divisions distant, from half an inch to an inch or more apart, 

 the upper gradually closer together. Secondary and lateral branches repeatedly 

 divided alternately ; the general outline lanceolate or somewhat rhomboid. Ramuli 

 opposite, a pair springing from every internode of the frond at a short distance 

 below the node, distichous, a quarter to half a line long, erecto-patent, quite simple 

 spine-like, subulate, tapering to an acute point. Articulations in the lower part of 

 the stem six or eight times as long as broad, without veins ; in the upper branches 

 gradually shorter, near the apices twice or thrice as long as broad, the terminal 

 ones shorter than their breadth. Articulations of the ramuli once and half or twice 

 as long as broad. 



I have as yet seen but a solitary American specimen, and it is without fruit. 



15. Calithamoton cruciatum, Ag. ; filaments short, in globular tufts, sub- 

 fastigiate, alternately decompound ; branches erect ; ramuli at every node in pairs 



