254 THE DISPERSION OF BRITISH PLANTS. 
species. Whether this be the case or not, we at any rate find that 
our plants with ex-albuminous seeds have a "lower degree of dispersion 
than those with albuminous ; and that among the latter differences in 
the nature of the albumen are accompanied by variations in the average © 
range; plants in which the albumen is farinaceous exceeding in this 
respect dupe in which it is fleshy, dense, or horny. 
Spee Average. 
ats With albumen floury or mealy oe 
fleshy or horny ; 6°80 
i = absent or very scanty ; 6°55 
This accords with the pepe of Mr. Darwin on the resistance 
of seeds to sea-water; in so far as the two pong which he foun 
were soonest killed, Leguminosee ant Malvae have no albumen; 
e of the five orders, which retained their vitality lo longest, Chenopo- 
pane Polygonacese and Srvaine have a floury, Solanacee a fleshy, 
and Umbellifers a dense album 
Dispersion dea: to Classification. 
Large Genera . Darwin, in support of his views of the nature 
of a * a addnces the fact that large genera comprise bec 
Gencral diffusion over er area they occ 3rd, Commonness, oF 
upy: : 
being represented by an abundance of individuals : "and 4th, a 
di 
or a tendency to proce varieties differing from the typical form. 
subsequent comparisons e in this connection, and show that a range 
ore 
oe Average. 
362 rBelaclal to 25 large haart 4 : : 7.38 
hye Belonging to smaller genera . : 6°82 
ral Diffusion, —On this point t have iced Mr. Watson's 
census ot counties in the “Compendium.” Classed according to his 
figures therein given :— 
Species. Average. 
150 Poaad : in 90 or more counties . : . 8-01 
336 Found in 60 to 89 counties ‘ : 724 
665 Found in less than 60 counties ; 6°65 
Commonness.—Taking ide our best-known Floras, 
averaged the plants that “ therein described, as “common,” “ abu 
dant,” “ple ntiful.” 
pa . Average 
319 Gendrally common . : é - . bar 
83 Partially common : ‘ . : eed 
749 Less plentiful, or rare ; 4 6118 
Variability.—Regarding as variable all species « of which m 
ore than 
one form is distinguished. bie Professor Syme in ‘ ‘ English Batany 
I have 
“1 
: 
: 
; 
ee 
Me 5 PAR 
