Botrydina vulgaris, Brebisson, a primitive Lichen. 
BY 
ELIZABETH ACTON, B.Sc. 
University Scholar , Birmingham. 
With Plate XLIV, and a Figure in the Text. 
I N the more recent systematic accounts of the Thallophyta, Botrydina 
vulgaris has almost invariably been placed as a green alga, the nature 
of which was not thoroughly understood. In order to clear up this 
uncertainty it was suggested by Dr. G. S. West that I should thoroughly 
investigate some living material of this plant which he had obtained 
amongst Mylia Taylorii, Canipylopus flexuosus , and other Bryophytes, in the 
damp woods in the vicinity of Capel Curig, Carnarvonshire. 
The earliest description of Botrydina vulgaris is that given by Brebisson 
in Meneghini’s ‘ Nostochineae * (’41), 1 in which publication it is placed as 
a member of the Nostocoideae. It is included by Kiitzing (’49) 2 in his 
‘ Species Algarum ’ in the Palmellae, and he gives as his reference ‘ Breb. 
Nouv. genr. d’Alg. (’39) \ I can only find, however, one paper by 
Brebisson with the title referred to, 3 and in this there is no mention of 
Botrydina , nor can I find any reference to it earlier than Brebisson’s com- 
munication to Meneghini (’41). 4 
It is figured by Kiitzing (’49), 5 and for the first time short unseptate 
filaments are shown appended to the more solid portions of the thallus. 
Rabenhorst (’68) 6 and Kirchner (’78) 7 have each given a brief dia- 
gnosis of it, and placed it in the Palmellaceae, but these descriptions do not 
strictly correspond with the original one given by Brebisson. 
1 Meneghini, ‘ Monogr. Nostoch. Ital./ Atti R. Accad. Sci. Torino, ser. ii, tom. v, 1841, p. 98, 
Tab. XIII, Fig. 2. (Hassall gives a translation of this in his Brit. Freshw. Alg., 1845, p. 320, and 
an extract from this translation is given by Cooke, Brit. Freshw. Alg., 1884, vol. i, p. 14.) 
2 Kiitzing, ‘ Species Algarum,’ 1849, P* 2I °- 
3 Brebisson, ‘ Description de deux nouveaux genres d’Algues fluviatiles, avec 2 pi. col.’ (Ann. 
Sci. nat., 1844, vol. i.) 
4 Meneghini, loc. cit. ( e Botrydina vulgaris , Breb. in litt.’) 
5 Kiitzing, Tabul. Phycolog., 1845-9, v °l* h Tab. 10. 
6 Rabenhorst, Flor. Europ. Algar., iii, 1868, p. 37. 
7 Kirchner, Alg. Schles., 1878, p. hi. 
[Annals of Botany, Vol. XXIII. No. XCII. October, 1909.] 
