Morphological Notes. 
BY 
Sir W. T. THISELTON-DYER, K.C.M.G., C.I.E., F.R.S., 
Director , Royal Botanic Gardens , Kew. 
With Plates XXI-XXIII. 
IX. A Kalanchoe Hybrid. 
HEN two distinct species are crossed, one would 
V V expect, a priori , the offspring to exhibit a c blend ’ 
of the parental characters. And this appears to correspond 
largely with experience. Thus Darwin states : ‘As a general 
rule, crossed offspring in the first generation are nearly inter- 
mediate between their parents’ (Variation of Animals and 
Plants, ii. 48). 
Such cases occur in nature, and before their real origin was 
understood they were regarded as intermediate species. Thus 
Geum intermedium stands between G. rivale and G. urbanum. 
But Bell Salter by crossing these two species proved it to be 
a hybrid. 
The rule is, however, by no means invariable, and Romanes, 
writing in 1881, remarks: e Until recently the interest attach- 
ing to hybridism was almost entirely of a practical nature, 
and arose from the fact, which is of considerable importance 
in horticulture, that hybrids are often found to present 
characters somewhat different from those of either parent 
or species’ (Encycl. Brit., xii. 422). Darwin states the same 
[Annals of Botany, Vol. XVII. No. LXVI. March, 1903.] 
