372 
ON CROSSES AND 
in the plant, though there may be a want of sufficient energy 
under certain, or perhaps under ordinary, circumstances. 
Many centuries of experimental cultivation must elapse be- 
fore the subject can be, if ever, fully understood ; and I can- 
not suppose that my present view of it will not require to be 
modified by the results of future investigation. For instance, 
there seems little prospect of being able to answer why the 
hybridizing process is so easy in some genera and so difficult 
in others, if equally facile of access, unless it shall be found 
to arise from greater or less constitutional conformity. 
The genus Calceolaria affords greater facility than most 
others, because its stigma is nearly obsolete before the pollen 
of the flower is ready, and, in the earliest stage of the bud, it 
is easy to lift up the corolla, and take out the anthers, which 
are then comparatively large and exposed, and the stigma 
may be fertilized at that early period, when it is defended by 
the covering of the corolla from any accidental intrusion. 
Amongst the Amaryllideae there is for the most part much 
facility of performing the operation in the several genera, 
the anthers not being reversed to display the pollen till a 
little while after the expansion of the flower ; yet in the 
genus Hippeastrum there is a complete readiness of all the 
species to intermix when crossed artificially, and in the 
genus Crinum nearly so, while in Zephyranthes it is ex- 
tremely difficult to obtain hybrid seed, and repeated disap- 
pointments occur from the escape of some particles of the 
natural pollen in taking out the anthers. In the genus 
Crinum one unintelligible impediment appeared for a long 
time to exist. C. Capense, which bred freely with every 
other species, refused to be fertilized by the tropical Cape- 
coast kinds, Broussonetianum, and petiolatum or spectabile. 
A seedling has, however, at last been obtained at Spofforth 
from C. Capense by the latter, which I believe to be correct, 
and it can scarcely be doubted that the difficulty arises from 
some constitutional peculiarities in those plants. In general 
hybrid plants have been found to be excessively florid, but 
sometimes the contrary has been the case, and there appears 
to be some impediment to the perfection of their blossom. 
The mule between Hymenocallis disticha and rotata, which 
was raised many years ago, whether it be in the stove or in 
the open air, where it grew against the front wall of the 
stove, throws up, after its proper time of flowering, an abor- 
tive scape, on which the buds are dead and discoloured, as 
