354 
ON CROSSES AND 
(melons, See.), can be intermingled; but, the names used not 
being of general currency, I cannot state accurately the re- 
sult. Dr. Wiegman extended bis experiments to varieties of 
oats. The accuracy of bis observations and those of Sageret 
ought to be thoroughly investigated, and the results produced 
before the public ; and a more useful office, connected with 
its pursuits, could not be undertaken by the Horticultural So- 
ciety of London, than to pursue those enquiries and extend 
them to other vegetables. An observation made by Gaertner 
and Wiegman (Berlin, 1828) as well as by Mr. Knight, that 
the offspring of hybrids revert to the maternal and not to the 
paternal type, is certainly erroneous, and Wiegman admits 
that tobacco (Nicotiana) and oats may be made by crossing 
again either to revert to that of the mother, or advance to that 
of the father. The offspring of the mule Passiflora ccerulea- 
racemosa, both in Mr. Milne’s garden and in mine, have noto- 
riously approximated to the type of the father, and lost alto- 
gether the red colour of the original mother. It is certainly 
not correct as a general law, though some have stated it, that 
the number of seeds in one pericarp is smaller in hybrid, 
than in cases of natural, impregnation ; it is true in some 
cases, and the reverse occurs in others. With respect to the 
conditions stated by Professor Rennie, as necessary to ensure 
success in crossing vegetables, it must be observed that the 
first, namely, that the blossoms should be nearly in the same 
state of advancement, is not accurate; for in some kinds, as 
for instance, Calceolaria, that which is to bear the seed should 
be much less advanced than that from which the dust is taken ; 
and in others, as Pelargonium and Alstrcemeria, it should be 
much more advanced. In truth, the moment should be 
seized, when the stigma in the flower which is to bear the 
seed, and the pollen in the other, is in perfection. The se- 
cond condition stated, that the anthers should be cut out early 
in the morning, is equally liable to objection, and cannot be 
applicable to all flowers, some of which blow in the morning, 
and others in the afternoon or evening. The necessary con- 
dition is, that the anthers be removed from the flower that is 
to produce the seed before the dust can escape from them ; 
for which purpose in many cases, as for instance in Crocus, 
Erica tetralix, and others, the flower must be opened with great 
difficulty at a very early stage. The plant must be then 
placed in a situation where no natural dust can reach it, 
brought either by the wind or by insects ; and the pollen 
