274 COMMENTARY ON THE PLANTS IN 
which, under the designation “ Cochenille végétale,” a chemical ana- 
lysis has been given by Vauquelin (Mém. du Mus. vi. p.345). The 
presence of a red pigment, capable of becoming fixed, leaves no doubt 
as to the nature of this vegetable, which is found at Rio de Janeiro, S. 
Paulo, S. Catharina, and Minas, in such quantities, that its collection 
may be recommended for dyeing purposes. The fructification of this 
Lichen is unknown; while the two other species, Hypochnus nigro- 
cinctus, Ehrenb. (l. c. t. 17. f. 4) and H. albo-cinctus, Mont. (l & - 
p- 368) are thallus forms of Chiodecton umbratum and Ch. lacteum, Fée. 
Comp. Montagne in Ann. Sc. Nat. 3 Ser. vol. xvi. p. 76. 
Alge. 
These are not mentioned at all by Marcgrav, and only one species 
by Piso, in whose first book de aere, aquis et locis (ed. 1648, p. 3), 
while giving an account of the weeds which prevail in the Brazilian 
ocean, the Sargasso of the Spaniards (Sargassum bacciferum, Ag.) is m- 
troduced, and more in detail in the second edition, p. 266, with an 
annexed woodcut, representing the ordinary form of this remarkable 
seaweed, without being copied from the earlier authors (Taberng- 
mont. ed. 1625, ii. p. 208; Lobel, Obs. p. 633, and Parkinson, Theatr. 
p. 1281). Acosta had already noticed (Aromata, ed. Clusii tertia 
1579, p. 87) that seamen were in the habit of eating the plant, both 
raw and boiled, as a remedy against urinary troubles. Piso repeats 
the observation. 
This class of Brazilian vegetation, both of fresh waters and the se 
coasts, has hitherto been comparatively little examined. I have given 
seventy-nine species, contained in several groups of the order, in Flora 
Bras. i. 1833; and St. Hilaire's species, determined by Greville and 
published the same year, amount to forty-five. "The algological labours 
of Montagne, of more recent date, have augmented the number to 141 
species in Kiitzing’s Species Algarum, namely, seventy-five species of 
the section Isocarpee and sixty-six of Heterocarpee of this author. 
Lichens, Mosses, and Hepatice are not mentioned by our authors, 
and therefore beyond our limits. 
Ferns. 
Maregrav speaks of this class of plants in the 2nd chapter of his 1st 
book (ed. 1, p. 2); Piso in the 54th chapter of his 4th book (ed. 2, 
P- 233, 234). The former has some Leyuminose among his Ferns, of 
LJ 
