ULVACEA, 129 
and folded. Quaternate granules beautifally arranged in squares, con- 
tained in larger ones, and separated by parallel pellucid lines, the whole 
compared by Agardh to the walks and parterres of a garden. Annual. 
Found throughout the winter and early spring.—Eng. Bot. p. 111. 
at L. fig. 1. Plants slightly magnified. Fig. 2, portion of a frond 
x 400. 
Prasiola furfuracea. Menegh, Cenni. p. 36. 
Forming a furfuraceous stratum, more or less expanded, dark 
green. Thallus about a line long and broad, dilated from the 
short stem-like base into a fan-like lamina; margin slightly 
undulate and repand, often emarginate at the apex or lobed. 
Cells angular, arranged in regular quadrate, or almost quadrate 
areolas, 
Sizz. Cells -014-:016 x *004-:006 mm. 
Jessen, Mon. Pras. t. 2, f. 1-10. Rabh. Alg. Eur. iii, 309. 
Lagerstedt Pras. p. 32. 
Ulva furfuracea, Grev. Sc. Crypt. Fl. t. 265. Eng. FL. v., p. 
812. Harvy.Man.171. Eng. Bot. ed. ii, p. 112. Grev. Alg. 
Britt. 176, t. 18. Mack. Fl, Hib. 244, 
On damp walls and rocks, 
‘“‘ Fronds closely tufted, forming a vivid green stratum, a yard or more 
in extent, two or three lines in length, erect, obovate, truncated, and 
usually eroded at the top, tapering at the base into a longish claw; 
margin inflected, substance firm, and void of lubricity. Cells in fours, 
It does not adhere to paper.” — Carm. 
Plate L. fig. 5. Fronds slightly magnified. Fig. 6, young frond X 400. 
Fig. 7, lower portion of mature frond X 400. 
Prasiola stipitata. Suhr. in Jessen Mon. t. 2, f. 11-16. 
Stratum cespitose, expanded, dark green. Thallus of 
variable form and size, commonly one to two lines, rarely four 
lines long ; dilated upwards from a stem-like base (lanceolate, 
obovate, obcordate, reniform, flabelliform, &c.), often truncate 
at the apex;-margin slightly repand; cells in the stem-like 
base in series, in the upper part disposed in small regular 
areolas. 
Size. Cells :005--007 mm. 
Jessen, Prasiola p. 16, t, 2. Rabh. Alg. Eur. iii., 309. 
Lagerstedt. Pras. p. 36, fig. 4. 
On rocks by the sea, &c. 
Jessen, in his monograph of this genus, gives figures of the fronds of 
some Irish specimens of the above species, which he had seen and 
examined. It is, on the faith of this, included here, although it appears 
to be the most marine of any of the four. 
Plate L. figs. 8.9. Fronds of P. stipitata magnified 4diam. Fig. 10, 
young frond X 400. Fig. 11, part of mature frond X 400. All after 
Jessen. 
