98 SPH^ROCOCCOIDE^. v. 



raary leaf, by repeated proliferous development, resulting in a much branched, subdi- 

 chotomously or secundly divided, globose, flxstigiate frond, two or three inches in 

 diameter. Each individual leaf is from half an inch to an inch long and about half 

 a line broad, narrow linear-lanceolate, obtuse at the base, much attenuate at the 

 extremity, which is invariably, on very numerous specimens which I have exa- 

 mined, strongly rolled inwards, and cannot be unrolled without difficulty, imme- 

 diately rolling up again Avhen released. The margin is quite entire ; within it is a 

 wide border, occupying more than a third part of the breadth of the leaf, composed 

 of naiTow cylindrical cells disposed in obliquely ascending lines at an angle of 

 about 45° with the midrib ; and throughout this border the membrane is raised up 

 in oblong undulations having a common direction with the lines of cells, and 

 appearing more strongly coloured than the surrounding parts. The portion of the 

 lamina between the border and midrib is composed of hexagonal cells of which the 

 innermost are largest. The midrib is of the same structure as in D. tenuifolla, but 

 formed of larger cellules. In old specimens it becomes, when denuded, thickened 

 into the setaceous stem and branches of the compound frond. Conceptacles very 

 convex, more than hemispherical, borne on the midrib. Tetraspores in small irre- 

 gular sori, one at each side of the midrib in the smaller leaves. Colour a pale rosy 

 red. Substance extremely thin and delicate. In drying, it adheres most closely to 

 paper. 



Plate XXII. A. Fig. 1. Delesseria involvens, the natural size. Fig. 2. Some 

 leaves, growing proliferously ; /z'^. 3. a leaf, highly magnified to show the structure ; 

 jig. 4, tetraspores lying among the surface cells ; all more or less highly magnified. 



Sub-genus 4. Caloglossa, Harv.; Frond dichotomous^ articidato-constricted, rooting 



at the forks, livid purple. 



1 1. Delesseria Leprieurii, Mont. ; frond livid-purple, linear, dichotomous, either 

 rooting or proliferous at the forks ; the space between each furcation linear-lanceo- 

 late ; the ultimate divisions attenuate, bifid at the apex ; midrib articulated, three- 

 tubed ; conceptacles nearly spherical, on the midrib ; tetraspores in lines obliquely 

 drawn from the midrib to the margin near the apices of the branches. Mont. An. 

 Sc. Nat. 2nd ser. vol. xiii. p. 196, t. 5, fig. 1. /. Ag. Sp. Alg. 2, p. 682. Hypo- 

 glossum Leprieurii, Kiitz. Sp.Alg. p. 875. (Tab. XXII. C) 



Hab. In tidal rivers, growing on stones, woodwork, or on pha;nogamous water 

 plants, &c. Discovered in Xorth America by Prof. Bailey in the Hudson at West 

 Point, and found more recently in the Ashley and Cooper Rivers, S. Carolina, and 

 in several rivers of Georgia and Florida. Apalachicola, Capt. Pike. (106). (v. v.) 



Frond one to two inches high, from half a line to a line in diameter, many times 

 regularly dichotomous, constricted at the forks, and traversed by a slender midrib. 

 At the point where the midrib bifurcates, there is generally formed a small rootlet 

 or process by which the plant attaches itself when young. Afterwards, when the 



