Annie C. Maybrook. 
243 
NOTE ON THE BIOLOGY OF FEGATELLA CONICA. 
By Annie C. Maybrook. 
[With One Figure in the Text]. 
HE following investigation of variation in the thallus structure 
| of Fegatella conica was carried out on plants found, during 
July, 1913, growing in a small hole in a high hedge bank, near 
Wetton in Derbyshire. The hole was broad-mouthed, narrowing 
at the back where there was a continuous dripping of water. It 
was thickly overgrown inside with plants of a thalloid liverwort 
(which proved to be Fegatella conica ) also present on the bank 
around the hole. The plants shewed great variation in form and 
size of the thallus, and in the number of spots, which indicated the 
position of the air chambers. 
The light intensity was measured at different positions in the 
cavity by means of Wynne’s exposure meter. Samples of thalli 
were taken from these positions, and later on their structure was 
investigated. In none of the forms were any sexual organs present, 
but the flask-like form of the assimilating filaments was sufficient to 
identify the liverwort as Fegatella conica. The light intensities at 
the different positions were expressed as fractions of the total 
daylight outside the cave, which was taken as unity. 1 These 
fractions will be referred to as the fractional light intensities at the 
different positions. Forms of thalli will be referred to as Forms 
I, II and III, corresponding to positions at which the fractional 
light intensities were -046, -043, ’0073, respectively. Forms IV and 
V are from dry and wet positions respectively, corresponding to the 
same fractional light intensity, namely ’0041. 
The thallus of Form I was broadly dichotomising (Fig. 1, 7), and 
shewed the following typical 2 structures (Fig. 1, 2). (1) Air chambers 
with elliptical pores, and flasked-shaped assimilating filaments. (2) 
Ventral scales. (3) The two kinds of rhizoid—tuberculated and 
smooth—the tuberculated rhizoids produced in bundles in the axils 
of ventral scales, and running horizontally, approximating to the 
under surface of the thallus, the smooth-walled rhizoids growing 
vertically downwards. (4) Mucilage sacs in the midrib and in the 
lateral wings of the thallus. (5) Two or three rows of assimilating 
1 Cf. Wiesner’s method for the “ Lichtgenuss ” of plants: J. Wiesner, 
“ Der Lichtgenuss der Pflanzen,” 1907, p. 4. 
3 F. Cavers. “ On the Structure and Biology of Fegatella conica Ann. 
Bot., Vol. 18, 1904. 
