726 



The surface of the stem is perfectly without ridges or furrows ; the 

 number of joints is forty : the colour of the internodes is white, with 

 the slightest tinge of green, but those on the lower part of the stem 

 often change to intense black: the black makes its first appearance in 

 spots or blotches, giving the stem a singularly variegated appearance, 

 but it rapidly spreads, and finally entirely occupies all the lower in- 

 ternodes. The sheaths, at the stouter part of the stem, are fully half 

 an inch in length, and the teeth are as much more : the former have 

 about thirty-two deep and distinct striae, which are furnished w^ith rows 

 of siliceous particles at their edges : the spaces between the strioB have 

 broad shallow furrows. The teeth are slender, setiform, closely ap- 

 pressed to the stem, frequently adhering at the summit in twos and 

 threes, and furnished with dilated, semi-membranous, somewhat rag- 

 ged edges at the base. The sheaths are pale green, with a distinct 

 blackish ring at the summit ; the teeth are black, with the membra- 

 nous edges brown, and, in the lower sheaths, often clothed with a 

 brown, byssoid pubescence. Each of the joints, with the exception 

 of five forming a slender apiculus at the summit, and six nearest the 

 ground, is furnished at the base of its accompanying sheath with a 

 whorl of slender branches : those of the lower sheaths are short and 

 recurved, while those near the summit are nine inches in length, and 

 nearly erect : the varied direction of the branches is shown at fig. a. 

 The number of branches in a whorl is very various : the respective 

 numbers, counting from the summit, are these : — five, six, seven, 

 eight, nine, ten, thirteen, fourteen, fifteen, sixteen, eighteen, twenty, 

 twenty-five, twenty-nine, thirty-three — repeated eleven times, thirty, 

 twenty-eight, and sixteen, making a total of six hundred and seventy- 

 eight. The colour of the branches is a delicate green, so beautiful as 

 to attract the eye at a considerable distance. Each of these branches 

 is composed of about eight or nine longish joints, and each joint ter- 

 minates in a loose sheath : the branches have either eight or ten ribs, 

 imited in pairs, and rough with siliceous particles : the sheaths termi- 

 nate in four or five teeth, each furnished at the extremity with a slen- 

 der black bristle : a pair of ribs ascends into each of the teeth, and 

 each rib is furnished, near its termination, with a series of rather long 

 siliceous points, which give it a pectinated appearance. Such may be 

 received as the descrijDtion of a stem of normal size and characters, 

 and the variations are very unimportant, chiefly consisting in size and 

 number of branches, but rarely interfering with the figure of the frond, 

 unless caused by circumstances, either of wet or drought, both appa- 

 rently uncongenial to i<s perfect development. One character, how- 



