Garden and Forest 6(256): 28-30 (January 18, 1893)
AND BIGENERIC HYBRIDS
The production of a genuine hybrid from two plants recognized as members of distinct genera is an occurrence of some interest, both to botanists and cultivators. The last case of this kind is that of Urceocharis Clibrani, the history of which is as follows: In July last, Messrs. Clibran & Son, of Altrincham, Cheshire, exhibited, under the name of Eucharis Clibrani, flowers which they said were from a plant raised by them from Eucharis grandiflora and Urceolina aurea. The flowers attracted little notice at the time, but a few weeks later, Dr. Masters published in the Gardeners' Chronicle a figure and description of Messrs. Clibrans' plant, which he had renamed as above, the generic name being a compound of that of the two parents. A few days ago Messrs. Clibran sent flowers of the plant to Kew for examination, and Mr. Baker is satisfied that it is a hybrid from the two parents named. The general habit of the plant appears to be like that of the Eucharis, the leaves being as large, the scape stout and eighteen inches long, bearing an umbel of eight flowers. In the flowers, however, we get some evidences of the Urceolina, the lower part of the tube being slender, the upper urceolate or campanulate, and the segments recurved at the tip. As a garden-plant this hybrid is likely to prove useful, the flowers being pure white, graceful, three inches long and two inches across the mouth. The buds are white, with green tips. The plants appear to bloom freely and frequently, Messrs. Clibran having had them in flower in July, August, and again in December.
The question arises, Are we to accept the Urceocharis as a genuine bigeneric hybrid, or to look upon it as conclusive evidence that the parents belong to one genus? Dean Herbert held the view that bigeneric hybrids were impossible, the occurrence of so-called hybrids being presumptive evidence that botanists had been mistaken with regard to the genera concerned.
The only other recorded case in Amaryllidaceae is that of Cyrtanthus hybridus, which was bred in the garden of Sir Trevor Lawrence, from Cyrtanthus sanguineus and Vallota purpurea. Mr. N. E. Brown, of Kew, who described and named this plant in 1885, and whose knowledge of Cape plants is probably unsurpassed, said of it, "I think this plant can scarcely be claimed as an example of a hybrid between two distinct genera, but rather as proving a view that I have held for some time, namely, that Cyrtanthus and Vallota are not really distinct genera, but merely different types of form belonging to the same genus, just as one finds in many other genera, as, for example, in Rhododendron, Lilium, Erica, Gentiana, Pelargonium, etc."
Viewing the Urceocharis from this standpoint, we are, I think, forced to the conclusion that Urceolina and Eucharis belong to one and the same genus. The diagnosis of the two as set forth by botanists, including Mr. Baker, shows that there is very little difference between them; far less than we find between, say, some of the species of Cyrtanthus, Narcissus or Hippeastrum. Urceolina itself, as now constituted, is made up of three species, one of which is almost everywhere known as Pentlandia miniata.
The "bigeneric" hybrids already recorded are very few, most of them being Orchids. Mr. Rolfe has dealt with the Orchids in a paper which he read before the Linnaean Society in 1887, afterward published in the society's journal.
He follows Dr. Masters in designating these hybrids by compounding for them the names of the two parents, such as Phaio-calanthe, Laelio-cattleya, Sophro-cattleya, Zygo-colax, etc. No one acquainted with Laelias and Cattleyas would object to their being united to form one genus, and Sophronitis might, with equal reason, be included with them, these three genera being, confessedly, very closely allied. Calanthe Veitchii was a supposed bigeneric hybrid until Bentham showed that Calanthe vestita and Limatodes rosea, its parents, not only belonged to the same genus, but were closely allied species. Phajus and Calanthe are very near allies, if we compare such species as Phajus veratrifolius with Calanthe masuca, etc., the botanists' opinion, notwithstanding.
Philageria Veitchii, the offspring of Philesia and Lapageria, only proves what might easily have been admitted without such proof—namely, that the two plants belong really to one genus.
The whole system of classification is admittedly arbitrary, and the division of plants into genera is necessarily often only a temporary arrangement, to be reconsidered when more is known. In England we keep the genera Aloe, Gasteria and Haworthia distinct, but many Continental botanists unite them under Aloe. We have a plant at Kew, Aloe Lynchii, which is the product of a Gasteria crossed with an Aloe. In England this is a bigeneric hybrid, elsewhere it is not. As a rule, however, the boot is on the other leg, Continental schools being the "splitters," English the "lumpers."
I know of seedlings which are the result of crossing Amaryllis Belladonna with Vallota purpurea. Should these prove genuine hybrids, we must, to be consistent, unite the Belladonna Lily with the Vallota, and these again with Cyrtanthus. To those who believe in bigeneric hybrids, this is a "rather large order," and yet any one who knows the genus Cyrtanthus must agree that it comprises plants that are remarkably like both the Vallota and Amaryllis. It would simplify matters if botanists would look upon the intercrossing of two plants as conclusive proof of their generic relationship. Of course, the converse of the above argument does not hold good—namely, that plants which refuse to intercross are therefore, ipso facto, generically distinct. We have tried again and again to cross certain plants of undoubtedly the same genus, such as Begonia, Crinum, Nymphaea, Rhododendron, etc., but have never succeeded. Failure in such cases is, no doubt, due to some slight difference, constitutional or other, and certainly not to any such structural differences as those upon which all good genera are based.