18 
SIPHONACEJE. 
branches, scarcely stipitate or subsessile, linear (in outline), 2-6 inches long, less than 
half an inch wide, pectinato-pinnate from a short distance above the base to the extremity. 
Rachis filiform, scarcely thicker than hog’s bristle, closely set with pinnae. Pinnce 
opposite, sometimes a little obliquely inserted, setaceous, 2-3 lines long, rarely straight, 
generally more or less incurved or falcate, their apices sometimes very acute, ending in 
a sharp mucro, sometimes bluntish. Substance when dry horny and semitranslucent. 
Colour a deep and rather dark green, the tips of the pinnae often yellowish' or orange. 
A native of the tropics generally, both of the eastern and western hemisphere ; occa- 
sionally straggling into the warmer parts of the temperate zone. It varies much in the 
diameter of the surculi, and somewhat in the length of the pinnae, but is easily recog- 
nised by the closely pectinate fronds, which resemble small green feathers. The speci- 
mens from Key West are peculiarly robust, and if compared with some slender varieties 
from the Pacific, might pass for different. But at Yavau, in the Friendly Islands, where 
this plant is common, I collected specimens both of the robust and slender form. 
Plate XXXVIII. C. Fig. 1 . Caulerpa plumaris , the natural size. Fig. 2, a pinna, 
magnified. 
4. Caulerpa Ashmeadii ; surculi naked, glabrous ; fronds erect, shortly stipitate, 
distichously pectinato-pinnate ; rachis subcompressed ; pinnae opposite (or suboblique), 
erecto-patent, straight, linear, somewhat incrassated at the very obtuse extremity. 
(Tab. XXXVIII. A.) ; 
Hah. Key West, rare. W. H. II., Samuel Ashmead, Esq. (v. v.) 
Surculi prostrate, distantly rooting, one or two lines in diameter, glabrous and 
glossy, collapsing, and mostly channelled when dry. Fronds scattered, rising from the 
upper side of the surculi, erect, each furnished with a stipes from half an inch to upwards 
of an inch in length, and closely pectinato-pinnate throughout. Each frond, pinnae 
included, is about an inch in breadth, and from four to six inches in length. The 
pinnce are half a line in diameter, three-fourths of an inch long, terete, and nearly linear, 
but more or less thickened towards the extremity, which is very obtuse, without trace 
of mucro or acumination. The substance when dry is horny and semi-transparent. 
The colour, when recent, is grass green, but in drying it turns to olive. 
The roots, Mr. Ashmead remarks, penetrate so deeply, and fix themselves so firmly 
in the hard sand, that it is with difficulty obtained, except in fragments. I regard the 
present as a distinctly marked new species, and have much pleasure in inscribing it to Mr 
Samuel Ashmead of Philadelphia, a gentleman who has already made some interesting 
discoveries among the Algae at Key West, and from whom many more may be expected. 
It is a much larger and stronger growing plant than C. plumaris , and remarkable for 
the very obtuse and almost club-shaped ends of the nearly straight pinnae. 
Plate XXXVIII. A. Fig. 1 , Caulerpa Ashmeadii, the natural size. Fig 2, a pinna, 
magnified. 
