HYBRIDISATION AND ITS FAILURES. 81 
again in 1835.” He mentions another instance of a sterile hybrid, called 
C. submersum, growing near Rio Janeiro in company with a small variety 
of C. erubescens. It was exactly intermediate between this species, which 
is aquatic, and C. scabrum of high ground. 
Of dissimilar species readily crossing, Dean Herbert * alludes to “ the 
prickly, angular Cereus speciosissimus, the flexible C. flagelliformis or 
Whip-plant, and the unarmed C. phyllanthocides, are nearly the most 
dissimilar ; yet they have produced mixed offspring, which readily bears 
edible fruit of intermediate appearance and flavour.”’ 
As illustrations of failures through constitutional differences, Mr. 
Buffham could obtain no success between perennial and annual species 
of Sunflower. With Rhododendrons, Mr. Veitch could get no hybrids 
between the East Indian hybrids and the Himalayan section, nor with 
the Ff. arborewm section. 
With Primroses, all British species fail to cross with Primula sinensis 
either way; and a significant fact is that all kinds of cultivated P. 
sinensis fail now to cross satisfactorily with the original wild form, 
according to Mr. Sutton’s experience; for though he was successful in 
obtaining ten plants from two crosses between P. sinensis ‘* Chiswick 
Red,”’ the female, and the original P. sinensis as male parent, all ten 
plants were very weak, and all died while in the first stage of flowering. 
Messrs. Sutton, however, have never been able to obtain any seed from 
the original P. sinensis when pollinated by any other variety. It is self- 
fertile. P. sim.“ Stellata,” apparently the same as ‘‘ The Lady,” and 
representing an early stage of cultivation, can cross (either way) with 
the normal cultivated forms. 
P. obconica failed to be crossed with P. sinensis by Messrs. Sutton ; 
but with Mr. Wright, of Chiswick, it so far succeeded that while the 
progeny resembled the mother; that of the second generation indicated 
the effect by bearing flowers with four, five, six, or seven petals, and 
once eight ; no such disorganisation occurred in the first generation. 
It would therefore seem to be a common, if not a general, rule that - 
species of different countries present greater difficulties in crossing than 
those of the same country, which probably grow under similar conditions. 
Thus, Fuchsia procumbens of New Zealand refuses to unite with the 
South American species, which readily intercross. Mr. W. G. Smith 
tells me that the outline of the pollen-grains of the former species is 
spindle-shaped, while of the latter it is a spherical triangle. 
Indian Azaleas are difficult to unite with the deciduous species of 
Japan. 
Begonia “ sempertiorens”’ section will not be successfully crossed 
with the tuberous section. 
Begonia ricinifolia x B. tuberosa (hyb.) produced seeds but no plants 
at the Utrecht Botanic Gardens. 
As instances of failures between species with marked morphological 
differences, yet residing in the same country, may be mentioned the 
“ Fancy” Pelargonium with the scarlets. Krelage failed also in attempt- 
ing Pelargoniwm gibbosum with P. zonale. Other failures between 
species crossed by this experimenter were Aristolochia elegans x A. bra- 
* Anuryllidacee, pp. 343 and 345. 
G 
