32 BOTANICAL INFORMATION. 
ly, and when covered with clear water, showing itself as a 
vast gelatinous mass, of a purplish-black colour, yet ex- 
hibiting its filamentous internal structure in the same way 
as the Batrachosperma do, when seen with the naked eye. 
Some of the specimens were found to attain a length of 4 feet. 
Of all our fresh-water Alga, none, as is well known by conti- 
nental specimens in our collections, make such beautiful 
specimens for the Herbarium, when neatly laid out on 
white paper: nor can any be more elegant among the 
marine Alge : even the colour improves in drying, becoming 
an intense purple, and giving out in desiccation a red- 
purple stain to the paper. 'The largest sized paper is, 
however, hardly big enough to receive the finest speci- 
mens, with their innumerable ramifications, which in them- 
selves are some feet long. Not only does the paper, on 
which they are preserved, but water, where the specimens are 
allowed to remain, receive a violet tinge; and linen, and 
cotton and silk, steeped in this fluid, become more or less 
deeply impregnated with it: but the colour, like that of 
many vegetable dyes, is very fugacious. A full history 
of this plant, and its chemical analysis, are given by Bory de 
St. Vincent, in the 12th vol. of the Annales du Musée, where 
the genus is first described, and named in honour of its 
discoverer, M. le Docteur Thore, a naturalist of Dax, and 
author of a Flora of the Département des Landes. In that 
memoir it is observed, as the result of the chemical analysis : 
* On voit par ces diverses expériences, combien le Thorea 
se rapproche des plantes qu'on. a nommé animalisées, parle | 
rapport des principes qui les constituent, avec ceux des _ 
êtres plus parfaits. Quant à Pemploi qu'on pourrait faire - 
de la fécule, il est facile; les peintres ont trouvé sa couche - : 
plus fine et plus brillante que celle des violets obtenus pr —— 
d'autres procédés ; mais je doute que cette belle couleur fat - 
trés-durable, à cause de l'action que Poxygène doit exercer | T 
sur elle, comme le démontre Pune des Spies queue — 
avons rapportés: E 
