86 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 
would not cross with the smoother-leaved forms, the flowers of which 
have blotches—at least distinct—on two petals only. \I do not know how 
far this has been corroborated, if at all. 
PartiAL Hysripisation.—A feature not infrequently observed by 
hybridisers is that a result of foreign pollen applied to the stigma of a 
different species is that it may take effect in varying degrees without 
securing any fertilisation of the ovules at all. 
One of the first botanists to note this fact was Wichura in the case of 
Willows, in which the following degrees of failure were observed :— 
1. “The catkins submitted to hybridisation wither as soon as the 
flowering is complete, and fall off. 
2. ‘*The ovaries swell and mature, but do not contain a_ trace 
of seed. 
3. “ The ovaries are quite filled with the silky hairs which clothe the 
funicle of the seed, which contains no embryo. 
4. “Seeds are present, but small, feeble, and~- incapable of 
germination. 
5. “Seeds apparently perfectly developed, but do not germinate. 
6. ‘ Seeds germinate, but the young plants are weak, and wither in a 
short time without further development. 
“The gradation in the number of seeds was very various. Sometimes 
the seeds were few, but fertile and active; sometimes, on the contrary, 
numerous, but with only a few fertile mixed with a number of abortive 
seeds ; sometimes tolerably numerous, without any such admixture ; but, 
in general, hybrids yielded on the whole a smaller number of seeds than 
plants impregnated with their own pollen.’’ * 
The above quotation was published in 1866; but Dean Herbert 
experienced the same results with Alstroemerias, and records Mr. Bidwell’s 
crossing Passiflora cwrulea with P. On unrane which bore a fine orange 
fruit, but devoid of seeds. 
Similar results have occurred repeatedly since then with other plants. 
Thus, just as Wichura found that silky hairs were the sole result of 
poilination in Willows, so is it in Orchids; as, e.g.,in an attempt at 
hybridisation by Mr. Veitch in the case of Phalenopsis Luddemanmana 
x P. Schilleriana, amabilis, and grandiflora. There was no seed, but 
hypertrophy of the placental hairs, giving the appearance of a pod full of 
cotton wool.t This has also occurred with many other Orchids. 
Phalenopsis grandiflora x Stanhopea tigrina, as well as Stanhopea 
eburna x S. tigrina, developed fruits; but no seed could be obtained 
which would germinate in the Utrecht Botanic Gardens.$ 
That the pollen may only affect the fruit is a well-known phenomenon. 
Thus, for example, Dr. Bonavia crossed the native Pumpkin of India, 
called Koomrd, with the American Squash pollen. The ovary enlarged 
and came to maturity, but did not contain a single seed. When it is 
fertilised with its own pollen, it is full of good seed. 
Mr. Veitch observes that ‘neither the Cattleyas nor the Brazilian 
* Abstract in Journ. R.H.S. New Series, vol. i. p. 63. 
t On Hybridisation amongst Vegetables. 
¢ The reader is referred to Origin of Floral Structures, p. 165 seqq., for a dis- 
cussion on the influence of the pollen-tube upon the ovary. 
§ Communicated by Mr. Krelage. 
