HYBRID INTERMIXTURES. 
341 
Sweet, in the second edition of his Hortus Britannicus, has 
since wisely added to Rhododendron the genera Rhodora 
and Azalea, with the exception of Azalea procumbens, 
though in his subdivision of the pelargoniums he has not 
kept in view sufficiently that certain and unalterable guide. 
The true meaning of species, not as the word used to be ex- 
plained by botanists, but as it is in fact used in all botanical 
arrangements, appears to be, the subdivision of the genera 
or kinds into branches, which naturally maintain themselves 
distinct even when approximated, though they maybe more 
or less capable of artificial or accidental intermixture; while 
a local variety will reproduce itself when isolated under 
particular circumstances of soil and climate ; and a semi- 
nal variety will not with equal certainty reproduce itself 
in the same form anvwhere, being more ready to inter- 
mingle with others of like origin. In fact, there is no 
real or natural line of difference between species and per- 
manent or descendible variety, as the terms have been ap- 
plied by all botanists ; nor do there exist any features on 
which reliance can be placed to pronounce whether two 
plants are distinguishable as species or varieties. Any per- 
son, who attends to the subject, will perceive that no bota- 
nist has laid down any precise rules by which that point of 
inquiry can be solved, and that the most variable, contra- 
dictory, and unsubstantial features have been taken by dif- 
ferent persons, and by the same person on different occa- 
sions, to uphold the distinctions they proposed to establish ; 
the truth being that such distinctions are quite arbitrary, 
and that, if two plants are found capable of interbreeding, 
when approached by the hand of man, they are as much one 
as if they were made to intermix more readily and frequently 
by the mere agency of the wind, or assiduity of insects ; and 
are not separable with more truth by any positive difference, 
than the varieties which cannot be prevented from crossing 
with each other when in the same vicinity. It remained to 
be ascertained whether there did exist a real, natural, and 
indefeasible difference between plants which could produce 
a fertile and those which could produce only a sterile off- 
spring by blending their races. It was my opinion that 
fertility depended much upon circumstances of climate, soil, 
and situation, and that there did not exist any decided line 
of absolute sterility in hybrid vegetables, though from rea- 
