IV. DICTYOTACEJE.— ZoNARiA. 105 



spores, each containing four sporules in tbe 2'>erispore ; jig. 5, section through one 

 of the concentric bands of paranemata ; fig. G, paranemata : the latter figures 

 more or less highly magnified. 



III. ZONARIA, Ag. 



Soot coated with woolly hairs. Frond flat, ribless, coriaceo-membranaceous, 

 flabelliform, entire or vertically cleft, the segments radiating ; the surface cellules 

 disposed in distinct longitudinal lines flabellately radiating from the base. Con- 

 centric lines indistinct. Fructification roundish or linear sori, formed beneath the 

 cuticle of the frond, and bursting through at either surface ; and composed at 

 maturity, of sjwres furnished with hyaline perispores, and of paranemata which are 

 mixed with the perispores. Paranemata club-shaped, articulated, numerous. 



In the more or less fixn-shaped frond this genus approaches Fadina, but differs in 

 the more opaque substance, only obscurely marked with concentric zones ; and in 

 the fructification, which is not disposed in regular, concentric lines. Here, too, 

 the spores and paranemata occupy the same sorus, while in Fadina they are sepa- 

 rated. Under a pocket lens the surface appears to be finely striated longitudinally^ 

 an appearance caused by the disposition of the superficial cellules, which are ranged 

 in lines proceeding from the base, slightly diverging one from another, and admit, 

 ting the introduction of new series of cells between each original row, as the frond 

 advances in growth. From this peculiarity results the fan-like form of the mature 

 frond. 



Ten or twelve species of this genus, from various parts of the world, are known 

 to botanists. All are natives of the warmer parts of the sea, with the exception of 

 Z. parvida, which bj' some authors is rejected from the genus. 



1. ZoNARiA lobata, Ag. ; frond erect, coated with woolly hairs at the base only, 

 membranaceo-coriaceous, broadly flabelliform, at first with a nearly entire margin, 

 then palmately cloven, or divided nearly to the base ; laciniae eventually elongate, 

 wedge-shaped, simple or again divided, concentrically zoned ; sori linear, formed 

 along the concentri lines. J. Ag. Sj?. Alg. vol. l,p. 109. Stypopodium fuliginosum, 

 Kutz. Sp. Alg. p. 663. (Tab. VII. C.) 



Has. On stones about low-water mark. Annual ? Keys of Florida : abundant 

 at Sand Key in February ; and sparingly, at the same season, at Key West, W. H. H. 

 Sand Key, Frof. M. Tuomey. (v. v.). 



VOL. m. art. 4. p 



