306 
SPECIES, VARIETIES, AND HYBRIDS. 
tice ; and it is singular enough that not only 
do botanists differ from one another, but they 
differ from themselves. Dr. Herbert con- 
tinues : — 
" The colour of the flower is one of the 
most uncertain features ; and yet if immut- 
able thi'ough successive generations, it is just 
as sound a botanical distinction as any other, 
whilst pubescence is a feature to which more 
weight is attached, and yet we sometimes 
find it as variable as colour. For instance, 
as to colour, the beautiful Convolvulus varius, 
figured in the Botanical Magazine as a 
variety of C purpureus, is very similar to 
that plant in everything but the colour of the 
flower. The seedlings of C. purpureus vary 
with every shade of purple, red, and white, 
having always five spots at the mouth of the 
tube, but no variation of colour is ever seen 
in the different flowers of the same seedling. 
Convolvulus varius has the opposite pecu- 
liarity ; the plants which I have raised, 
through twelve or thirteen generations, dif- 
fered not in the least from each other, but it 
would be difiicult to find two flowers upon 
any plant exactly alike in the marks of 
colour, but they never have the five spots in 
the tube ; and the natural ground is a sul- 
phureous white, with the inside of the tube 
pale purple, and the flowers are irregularly 
streaked with dark blue in infinite diversity. 
Sometimes an accidental flower, like a run 
carnation, will have the ground entirely blue, 
with streaks of a deeper colour, but no in- 
stance of a plant raised from its seed, with all 
its flowers alike, or spotted at the mouth of 
the tube, has been seen ; and therefore it ap- 
pears to be as truly a distinct species as if it 
had been distinguished by any other perma- 
nent feature. Permanent colour is also a 
principal feature in distinguishing the species 
of Anagallis. On the other hand, as to pu- 
bescence, the lovely Eddies suberecta does 
not appear to vary in colour, but in a pot of 
seedlings I have found one with the stems 
hairy, whilst the rest have them smooth. If 
that difference had been found in a wild spe- 
cimen, with some variation in the colour of 
the flower, the botanist mould have named it 
a distinct species, tmfil the experience oj^ cul- 
tivators had shown the difference to he un- 
certain." 
This raising of new varieties from seed is 
rapidly destroying many botanical distinctions; 
species so called are proved to be only seed- 
ling varieties, and many of the varieties 
from seed difl'er more from each othei>than 
plants which we have been told are distinct 
genera. 
" With respect to the fertility or bai'ren- 
ness of mule vegetables," continues the Rev. 
author of these remarks, " there is some mys- 
teiy which I cannot at present, and perhaps 
never shall be able to develop. All the 
mules I have raised between the African 
Gladioli have proved exceedingly fertile, in- 
deed certain of producing good seed from 
every flower ; yet the Gladioli cardinalis, 
hlandus, tristis, hif'sutus, and recurvus, from 
the intermixture of which some of those mules 
have been produced, are plants exceedingly 
dissimilar to each other, and could not pos- 
sibly be considered as varieties of one species. 
I have found no difficulty in crossing one 
of the mules produced from these with any 
third species : but the European Gladioli 
(which have not winged seeds, and ought to 
be considered as constituting a distinct genus) 
have as yet refused to breed with the African 
sorts. On the other hand, the hybrid C?'i- 
num Govenium has not produced any seed, 
either from impregnation with its own dust 
or with that of other Crinums, although I 
applied that of C. speciosissim,um and C. hre- 
vifolium. Its stigma was, however, quite 
perfect, and furnished with the usual tubular 
fringe, and the particles of its pollen, exa- 
mined with the microscope, though not very 
abundant, appeared to be furnished with the 
viscous juice which I consider to be the proof 
of fertility. I did not think of examining the 
interior of the germen till it had begun to turn 
yellow, but it appeared then as if there had 
been a deficiency of the embryo seeds in the 
germen, and therefore an incapacity of bear- 
ing seed. 
" The American AzaSfeas do not produce 
seed abundantly in this country, and one 
reason for this is that they are frequently en- 
tirely deficient in pollen, in consequence, per- 
haps, of the dryness of our atmosphere .or soil 
in spring compared with that of America. 
In the second week of May I was desirous 
of impregnating Rhododendron azaleoides, 
which had no pollen of its own, with that of 
some Azalea, but I could not find a single 
Azalea iiower that had any pollen. I touched 
its stigma therefore with the dust of Rhodo- 
dendron Catawhiense. The capsules swelled, 
and in August they appeared in fair progress 
to ripen the seed, but owing to the extraor- 
dinary drought (the plant not having been 
watered) the pods fell off; but they had re- 
mained on long enough to show that the 
germen had been apparently fertilized ; those 
to whose stigma the dust had not been ap- 
plied having withered long before. From 
this it should seem that the ovarium is not 
defective in that mule, and that it would pro- 
bably be fertile in America. My own mule 
Rhododendroife have pollen, though not 
abundant, and I think I should have obtained 
seed from them this year if their roots had 
not been inj ured by too much water in the pots. 
