LINNEAN SOCIETY OF LONDON. 881 
one or more species of grass belonging to the genus Epicampes; one 
species, viz., H. macroura Benth., was undoubtedly used. The local 
name is Zacato on, and hence the fibre is “sont amongst the 
Mexicans as Raviz de Zacaton. (2) A Mexican fibra or Ixtli, 
largely used in this country in the manufacture of nail-brushes, 
dandy-brushes, &c. The origin of this fibre has for a long time 
been obscure. Dr. Perry santsibuted to the Kew Museums in 1879 
fibre and brushes made from it, said to be derived from Agave 
Sechiquilla Torrey. This species is identical with A. Poselgerii 
Salmdyck, and A. heteracantha Zuce. A careful examination of the 
deri m livi 
in the place of animal bristles. — A paper was read by Mr. Patrick 
Geddes, ‘‘On Certain Factors of Variation in Plants and Animals” 
fo i 
race 
vray spike or umbel to capitulum or even fig, (8) of the ean 
ning of the axis hyo the flower itself, giving the transition from 
Hy Dongtsy through per to epigyny, (4) of the reduction and 
coherence of the ae pede te (5) of the reduction of stamens, 
(6) of — (7) of ovules. But opel constitute the leading 
modifications of ihe ftir ‘and the essential characters of the 
natural vas are then seen to continndaaly developed as a 
consequence of aly subordination and reproductive pre- 
onderance; natural selection furnishing more frequently the check 
to evolutionary change this the impulse or aid toit. Floral colour, 
too, is seen to have arisen in the same way, the reds and yellows of 
flowers, as of spring and autumn foliage, being simply the imperfect 
as vegetation of immaturity, reproduction, and decline irl ntthap 
The tendency to its accumulation is primarily associated with the 
by a insects, is not derived. ation of floral details 
hows many of the most peculiar “ adaptations ” to be more simply 
interpretable in terms of the characters of the leaves of whic 
of the rose, or the swollen leaves of the styles of Umbellifere, from 
their characteristic leaf-cases, but even the 
cupped stigma of violet or the springing eranilum, 
Passing next to the variation of plants under domestication, we 
find their apparent indefiniteness cleared up by the gaunt" - 
of change. The apparently obvious and generally accepted origin 
of spring plants through the natural selection of browsing mammals 
