276 
THE MEDITERRANEAN NATURALIST 
magma with lime and its low temperature. It i 
therefore seems that we should Look more to grai t ite 
and its derivative as fuses of limestones than to 
basic rocks. Why should not the basalts of Mull 
be the result of the contact of the granites with 
the underlying limestones? I have brought the 
subject forward, not with the intention of offering 
new evidence, but to again direct attention to such 
an important branch of vulcanological science. 
(to be continued ) 
Albinism and colour variation 
in Maltese wild flowers. 
by Dr. Alfred Caruana Gatto. 
In noting all the albinos and colour variations 
I happened to meet with in our indigenous plants 
I do not intend to give simply a list of them, but 
I wish rather to point out in what way such va- 
rieties take place jn plants such as our wild ones, 
when not subject to any artificial treatment like 
cultivation and when they are left to themselves 
under nature’s direct agencies. 
I have not analyzed and I believe I could not, 
even if I would, the various causes which led to 
them, and which I expect, are here just as any 
where else, the compositon of the soil, light, tem- 
perature and crossing; and my notes referring to 
such a circumscribed area as that of our Island 
have therefore no claim to stand good but with 
reference to our flora — they may however always 
be of some use for comparison with other floras. 
The occurrence of albinisms and colour-varia- 
tions in certain groups in preference to others 
and their relative frequency in such cases have 
led me to observe that few species are subject 
to hereditary and constant variation, and that the 
greater part are occasional variations due to indi- 
vidual causes and which though they perhaps re- 
peat themselves each year in the same species are 
not transmitted by heredity, which fact in case of 
albinisths does not astonish me, because consider- 
ing that they are generally due to a lack or dimu- 
nition of constructive faculty or at least that they 
are considered more as degenerated forms than as 
improved ones as it follows that this character, is 
little adapted for generative transmission. 
Of the constant colour variation the mosr 
remarkable is that of the yellow A<loni.< micro- 
carpa D.C., which in its typical form is of a 1 Tight 
red. This variety called by Gussone citrina is 
rarely found in rich soil and shows a beginning of 
degeneration in the floral envelope by the very fre- 
quent want of one or two petals, sometimes of 
all the petals which are scarcely developed. Bul- 
bous monocotyledons afford us also some heredi- 
tary albinisms, and we have thus Sc-H’i sieul 7 
var. Candida Guss., considered by some authors as 
a distinct species, but which nevertheless is no- 
thing else but an albino of the normal No s>cu!. . 
of which the flowers are of a lilac of various 
shades. All our Orchis offer also more less 
such a phenomenon, especially Anacaiaptis p : /ra- 
midalis Rich, which has two forms, one with rose 
or pale rose flowers flowering in March. April, the 
other with flowers of a deep purple which flowers 
in April, May: — The first form has often i;< flowers 
of a perfect white. 
What is to be noted next is the greater liability 
to albinism of flowers belonging to the cyanic 
series than those which fail under the xanthi 
series, and that, in that series the colours which 
most easily fade into white are the purple an .1 the 
lilac which are easily affected by the slightest 
causes. If it would be ascertained that this is not 
only the case with our flora but a general occur- 
rence in albinisms it would be explained by the 
fact mentioned by Prof Henslow in the Gardener's 
Chronicle p. 125 — Aug. 3, 18SD, that in the evolu- 
tion of colours in flowers, the xantliic series comes 
before the cyanic one, and that plants which have 
reached the higher stages in this evolution revert 
more readily to the more primitive colours than 
do those of which the colours have much greater 
stability, what is confirmed by Dr. Sorbffs assert- 
ion that of all colours yellow xanthophyll is the 
most stable under sunlight. We have therefore 
Labiates, Scrophulariacete and Valerianacem 
amongst the families which give the greater number 
of albinism, whilst Hypericimo and families which, 
contain many plants with yellow flowers give 
comparatively but few instances if any. 
The albinisms I have noted amongst our wild 
flowers are the following. 
