18 RHODOMELACEiE. v. 



quoted above, except that Lamouroux represents the splniferous ramuli shorter 

 than I find them. He received the plant on which he founds his species from 

 " North America," but was uninformed of the exact locality where it was gathered. 

 I have little hesitation, therefore, in adopting his specific name. Nor do I hesitate 

 to refer the A. muscoides, Grev., typified by Turner's plate 32, nor the A. militaris, 

 Lamour., to the same species ; for though my specimens from Key West are much 

 less copiously branched than the figures given by the authors just named, yet I 

 find such a series of connecting links in numerous specimens from St. Croix, 

 which I owe to Miss Dix, and specimens from Chili collected by Baron de Selding, 

 that I cannot point out any valid difiference. Some are scarcely branched, others 

 closely pinnate or bi-pinnate, and both forms sometimes occur in the same tuft. I 

 am not alone in this opinion, doubts of the validity of A. muscoides being held by 

 Dr. Montagne, {Nat Hist. Cuba, p. 43,) who has kindly sent me a specimen of 

 his plant, and it closely agrees with some of my Key West specimens. 



Plate XIV. A. Fig. 1 , Frond of Acanthophora Thierii ; the natural size. Fig. 

 2, a spiniferous ramulus ; jig. 3, cross section of the stem ; the latter figures more 

 or less magnified. 



2. Acanthophora Delilei, Lamour. ; much branched and bushy, decompoundly 

 pinnate or irregularly divided ; branches beset with long and short, sub-spiuiferous 

 ramuli, and with solitary, distant, short spines. Lamour, Ess. f. 44 ; Kiitz. Sp. 

 Alg., 858 ; Fhyc. Gen. t. 52, /. 4 ; Fucus naiadiformis, Delile, Egypt, t. 56,/. 1. 



Hab. At Sand Key and Key West, W. H. H. (No. 3.) (v. v.) 



Fronds in large tufts, 4 — 6 inches long, one-third of a line in diameter, exces- 

 sively branched from the base. Branches alternate or secund, rarely opposite, 

 spreading, simple below, beset with secondary branches above. These secondary 

 branches are often again pinnate or bipinnated with lesser ramuli of unequal 

 lengths. Ramuli either naked, or having a few distant, horizontal spines, or 

 regularly beset with alternate spines. The larger branches also are furnished with 

 scattered, simple, solitary spines. Substance cartilaginous. Colour dull purple, or 

 brownish, becoming very dark when dry, in which state the plant imperfectly 

 adhei'es to paper. 



This is a more slender and much more diffusely branched plant than the pre- 

 ceding, from which it is technically distinguished chiefly by the scattered solitary 

 spines, found on all the branches in greater or less plenty. Our specimens agree 

 in most respects with specimens from the Mediterranean, but I am not without 

 doubts, whether the differences indicated betw^een this plant and A. Thierii are 

 valid. 



