VALONIACEJE. 43 



Young and full grown specimens of the little Alga which constitutes the present 

 genus are so unlike that they might readily pass for diiFerent entities. The frond 

 originates in a dense mass of branching, horny-membranous, intricate, rooting fibres, 

 from which spring erect unicellular branches, or fronds. These are at first quite simple 

 and naked ; but afterwards develope from their summit two or three very closely placed 

 whorls of much branched ramelli, which form a dense, fasciculate capitulum. The frond 

 is then mature and resembles a little tree; or perhaps, more justly, a little mop. The 

 genus was founded by Montague in 1842, by a separation from Fenicillus. 



1. CHAMiEDOMS amiulata, Mont. An. Sc. Nat. Ser. 2, vol. 18, p. 261. Kutz. Sp. 

 Alg. p. 509. Nescea annulata, Lamour. Pol. Flex. p. 256. Corallina peniculum, Ell. 

 and Sol. Zoop. p. 127, tab. 1,fig. 5-8 and tab. 25,Jig. 1. (Tab. XLII. B.) 



Hab. Key West, rare. W. H. H., Dr. Blodgett. (v. v.) 



Root composed of many branching and clasping, tufted fibres, which issue from the 

 base and lower part of the stipes, and at length form a dense mat. Fronds tufted, 

 2-3 inches high, nearly a line in diameter, tubular, simple, membranaceous or some- 

 what horny, destitute of calcareous incrustation except in old age, when they are thinly 

 coated toward the base ; cylindrical, annularly constricted at short intervals as if 

 jointed, the internodes most apparent on old specimens, when the annular constric- 

 tions are deeper. In the young state the frond consists merely of such an annulated 

 tube, formed of a single cell. When this has attained the height of two or three inches, 

 it ceases to grow longer ; a septum is formed just below the summit, and a new cell 

 begins there to develope. This second cell is very short, and again divides, once or 

 twice, vertically ; so that the original tubular cell (now to be called the stipe) is 

 crowned with two or three minute cells, placed one above the other (Tab. XLII.^^. 3), 

 the terminal one being attenuated and pointed. These cells remain short and rudimen- 

 tary, but from their nodes dense whorls oi ramelli begin to grow (jig. 4), which finally 

 constitute a dense, mop-like capitulum. When fully grown the capitulum is an inch 

 or more in diameter, globose, very dense, composed of innumerable, crowded and inter- 

 woven, much branched, irregularly dichotomous, articulated filaments. The articulations 

 are cylindrical, constricted at the nodes and many times longer than broad ; but 

 variable in length. Colour, a bright, grass-green. Substance., membranaceous, rather 

 rigid and tough, not adhering to paper in drying. Thin slices of the tube, when 

 examined under the microscope, show concentric lines of growth, as in Dasydadus, &c. 



This plant is rare at Key West, and none of my specimens are fully grown. It is a 

 native of the West Indian Islands. 



Plate XLII. B. Fig. 1. Cham^doris annulata, the natural size. Fig. 2. A young, 

 unicellular frond, previous to the formation of the capitulum. Fig. 3. Apex of a frond 

 in a more advanced stage, showing the newly formed axial cells of the future capitulum. 

 Fig. 4. Apex of a still more advanced young frond, with the capitulum beginning to be 



