HYBRID INTERMIXTURES. 
345 
race, and that the triple cross is not an impediment. I have 
crosses raised by me between the yellow Linaria genistifolia 
and the purple purpurea, and also between Penstemon an- 
gustifolium and pulchellum, both perfectly fertile and sowing 
themselves about the garden, and, from my having given 
them many years ago to more than one nurseryman, become 
common. It is scarcely possible to assert that these very 
unlike plants are respectively one, and at the same time to 
distinguish them from the rest of their own genera, espe- 
cially the former. That whole portion of Amaryllideae which 
constitutes the genus Hippeastrum, and was confounded by 
botanists with a portion of the genus Crinum, not only inter- 
breed freely, but produce offspring invariably fertile, be- 
cause they are all of like constitution, and impatient of exces- 
sive moisture, though some will bear more cold than others. 
Amongst the Pelargoniums a similar convertibility has been 
found to exist within certain limits, which, if duly observed, 
will be sure guides to ascertain the genera, into which they 
ought to be subdivided, and by which the botanist, who is 
desirous that his labours should not be overturned hereafter, 
must be in a great measure ruled in classing them. 
Amongst the Cacti or Cerei the prickly angular specio- 
sissimus, the flexible flagelliformis or whip-plant, and the 
flat unarmed phyllanthocides, are nearly the most dis- 
similar, yet they have produced mixed offspring, which 
readily bears eatable fruit of intermediate appearance, 
colour, and flavour. The fruit of the speciosissimus is 
large, green, and well -flavoured, round oblong; that of 
phyllanthocides small, purple, and very inferior ; the mule 
from the former has purple fruit of a medium size and 
taste*. The cross from the former by flagelliformis is now 
ripening here a short angular fruit, quite unlike that of the 
mother plant. The fertility of these crosses, and readiness 
to vary the appearance and taste of the fruit, though derived 
from such very dissimilar parents, is one of the most striking- 
results of our experiments. I have had no opportunity of 
attempting to cross them with the plants called echino-cacti, 
but I do not see a single point in the generic character given 
of those plants which can uphold it, and I believe them to 
be of one genus with Cereus, and capable of intermixing ; 
but I have had no opportunity of examining the flower of 
any of the plants called Echinocactus myself. Amongst 
melons I have had the Cucumis osmocarpus from Mexico, 
