16 RHODOMELACEiE. 



2. Alsidium Blodgettii, Harv.; frond svib-compressed belo^y, terete above, decom- 

 pound pinnate ; pinna? alternate, patent, close, virgate, the lowest very long, set 

 with short, setaceous, spinous-toothed, alternate, distichous ramuli ; upper branches 

 short and sub-simple ; conceptacles pedicellate, inflated, urceolate, variously placed 

 on the ramuli. (Tab. XV. B.) 



Hab. At Key West, Dr. Blodgett, (No. 73.) St. Marks, Florida, Mr. Hooper. 

 Apalachicola, Capt. Pike (v. s. in Herb. T. C. D.). 



Frond of unknown lengtli, probably a foot or more. Branches pinnate or bi- 

 pinnate ; the lowermost pinnte long, simple or again pinnate ; the upper much 

 shorter or altogether abortive, so that the apices of the branches project, like long 

 tails, beyond the bushy part of the frond. All the divisions are very patent, the 

 primary and secondary ones almost horizontal. The secondary (or pinna;) are 

 distichous, about two lines apart, and are from two to three inches in length, about 

 the thickness of hog's bristle, gradually tapering to a point. Near the base they 

 are generally bare of ramuli, or are merely toothed, but for the greater portion of 

 their length are set with distichous bristle-shaped ramuli, a line apart and two or 

 three lines long. These ramuli are regularly spinoso-dentate. The conceptacles., 

 which are abundant on some of my specimens, are as large as poppy-seed, inflated, 

 thin walled, with a prominent, contracted orifice, and contain a very large tuft of 

 pear-shaped spores. They are placed either just above the axils of the ramuli, or at 

 their apex, or along their margin, and appear to be formed by a metamorphosis of 

 the spinous teeth which regularly alternate, in distichous order, along all the 

 branches and ramuli. A cross section of the stem shews a central cavity sur- 

 rounded by five primary cells, outside which several large cells are interposed 

 between the primaries and the peripheric cells. The colour appears to have been a 

 clear, full red, fading to yellowish on exposure. The substance is cartilaginous, 

 but somewhat tender, and the plant, in drying, adheres pretty strongly to paper. 



For a knowledge of this very interesting plant, I am indebted to my friend Dr. 

 Clodgett of Key West, whose name I have therefore bestowed upon it. At the 

 time the figure and description were made, I had seen but a single specimen ; but 

 have since received numerous and beautiful specimens from Dr. Blodgett, in all 

 important respects agreeing with that first found. Captain Pike and Mr. Hooper 

 have communicated, from the mainland of Florida, less perfectly preserved specimens; 

 which, notwithstanding some minor differences, I refer without hesitation to this 

 species. I think it can hardly be doubted to belong to the same natural genus as 

 A. Seaforthii, though abundantly distinct from that species. 



Plate XV. B. Fig. 1. A branch of Alsidium Bhdgettii, the natural size. Fig. % 

 apex of a branch, with toothed ramuli and conceptacles ; fig. 3, a conceptacle and 

 ramulus removed ; fig. 4, spores from the conceptacle ; fig. 5, transverse section of 

 the stem ; the latter figures more or less highly magnified. 



