rr.vv L85 



He greater Dumber of cells in the breadth of the frond, 

 and the presence of occasional Bhoii ramuli, would Beem to 

 be the characters by which JE. JRalfsii is to be known from 



the true /•;. i« rcursa. 



!. I L\.\. 



'Mo. latissima {The very-broad Ulva) j frond broadly -ovate or 

 oblong, flat, of a full-green colour, Linn. /'/. Shtecp. 



(An as, PL I. Will. Fig. 342.) 



riv;i Lactuca, Smith. U. Lactuca, var., Lightf. 



Hub. On rocks and Btonea in the sea, between tide-marks, and ex- 

 tending to ten fathoms water, or perhaps a greater depth. 



Annual. Summer and autumn. 

 An exceedingly common species, found on all Bhores, 



and nearly in all latitudes. Except on the extreme Ant- 

 arctic coasts, where all vegetation, save the Diatamacea % 

 is at an end. Ulva latissima may be said to Inhabil 

 shore. It is as abundant in the tropica as in the temperate 

 zone. 2sor do specimens from different countries exhibit 

 many minor points of difference. Some are of more rigid 

 texture than others, but there is little else peculiar about 

 them. The form is too variable among specimens from 

 the same locality, to found any characters upon Ltfi 

 dations. 



311. Lactuca (The Tjlfn<->< Ulva) ; "frond at first obovat 



. inflated, at length cleft down to the base; the segments 

 plane, unequal, laciniated, semi-transparent," /. . Sp. TL 

 p. L632. \ clas, PL LXXIII. Fig. 343.) 

 Hah. On ro< mells,|and the smaller Algse between tide- 



marks. Annual. May ami June. Generally distributed 

 round the British coa ts, but Less common than U.latisi 

 The characters by which this delicate plant may be dis- 

 tinguished from the more common ('. latissima are most 



obvious in an early Btage of -r->\\ tli. u hen the present plant 



forms an obovate Bac, uol very unlike a greatly distended 

 Enteromorvha ; while ('. latissima is at all periods of its 

 growth a tlat membrane. Other characters are found in 

 the Bubstance and colour. U. Lactuca is of a brighter 



and yellower green, and more glossy when dry : and its 



tly more thin and delicate than that o[' 



U. latu Im '. U. latissima is found a; all Beasons and 



*m every BnOre; bul I . / 3 Beldom seen 6XC 



