100 THE ORCHID REVIEW. [ APRIL, 1912+ 
he never allowed a seedling to be destroyed in his herbaceous borders until 
its identity was known. In this way all spontaneous hybrid seedlings had 
a chance of developing. The result was the appearance of a large number 
of hybrids of the most diverse genera, even including a hybrid between the 
Madeiran Orchis foliosa and one of our European kinds, and all by the 
interchange of pollen by insect agency. 
In the same way hybrids often occur in a state of nature where allied 
species grow intermixed. An enormous number of such plants are now 
known, though for a very long time botanists refused to recognise their 
existence, generally describing them as distinct species or as varieties of 
one or the other parent. Examples are common in Rosa, Salix, Epilobium, 
and numerous other genera, and in some cases have given rise to quite 
amusing discussions as to their identity. Among Orchids we may mention 
Odontoglossum, Cattleya, Dendrobium, Vanda, and even crosses between 
distinct genera, as Cattleya and Lelia, Cattleya and Brassavola, and 
between Orchis and Serapias and two or three other European genera. 
Hybridisation is largely a question of opportunity, and when species that 
will hybridise happen to grow together an interchange of pollen is sure to 
be effected by insect agency, and spontaneous or natural hybrids are the 
result. Such plants may often be recognised by their compound or 
intermediate character. 
The term hybridisation is often loosely applied to cross-fertilisation 
generally, but should strictly be limited to cases where the two parents 
belong to distinct species or are themselves true hybrids, for the term 
hybrid implies the union of organisms that have different properties and 
characters, and is something deeper than the mere cross-fertilisation of 
forms or varieties of the same species. 
Hybridisation consists in the application of the pollen of one species to 
the stigma of another, and the subsequent growth of the pollen tubes down 
the tissue of the style, and the fertilisation of the ovules; the process 
resulting in the union of two organisms having distinct ancestries, and thus 
showing intermediate characters or a combination of characters derived 
from the diverse parents. Hybrids from nearly-allied species usually 
exhibit a blend of the parental characters, but in those from widely- 
separated species one often finds a combination, the characters of one or 
the other parent being very marked in certain organs, and thus it is some- 
times possible to trace the parentage unmistakably. In some cases the 
resemblance to one of the parents is very marked, the other being only 
traced with difficulty, a phenomenon to which the term dominance has 
been applied. It has probably some definate relation to the ancestry of the 
parents organisms, and may be considered as a form of reversion. 
In the case of what are termed false hybrids the dominance is so 
