332 



CASSELL'S POPULAR GARDENING. 



seedlings that survive are so slow in arriving at the 

 flowering stage, that up to the present time not a 

 single plant has produced a flower, although the 

 plants continue strong and healthy in appearance, 

 and increase in size every year. One thing is 

 certain, the three-celled ovary of the Selenipeds 

 offers no impediment to the fertilisation by the 

 pollinia of Cypripeds with a one-celled ovary, for we 

 have plants raised from C. caudatum and G. barbatum, 

 and many other like crosses between other species 

 have yielded seed. 



" G. Sedeni was a remarkable cross in many respects ; 

 it was, in fact, raised from two crosses — C. Sehlimii 

 and G. longifolium, and the same two vice versa. It 

 will be observed that in this case one of the parents, 

 G. longifolium, is much mqre robust in habit and 

 growth than the other parent, C. Sehlimii. No 

 perceptible difference was observed between the 

 plants raised from the two separate crosses : they 

 agreed in habit, foliage, colour of flower, in fact in 

 every particular. No such similar result has been 

 obtained by us amongst Cypi-ipeds : a vice versa 

 cross between the same two species, produces seed- 

 lings that vary more or less from those produced 

 from the first cross. Thus G. tessellatum resulted 

 from C. barbatum and G. con color, and G. tessellatum 

 porphyrium from C. concolor and G. barbatum. We 

 have also an instance of two recognised species, each 

 being crossed by a third, but both crosses producing 

 like results. Thus C. longif 'olium and C. Sehlimii, and 

 C. Roezlii and C. Sehlimii, produced seedlings whose 

 flowers are indistinguishable from each other, 

 although, as might be expected, the foliage of the 

 G. Roezlii progeny is, like that of its parents, the 

 more robust of the two ; hence the specific rank of 

 C. Roezlii is very questionable. 



" Not only do recognised species of each section, 

 East Indian and South American, cross freely inter se, 

 but the hybrids also cross freely with them. The 

 beautiful C. cenanthum superbum has for its parents 

 the C. Harrisanum, itself a hybrid, and C. insigne 

 Maulei. As regards the habits and foliage of hybrid 

 Cypripeds, the progeny usually takes a form inter- 

 mediate between the two parents, but sometimes it is 

 more robust than either. 



" I may here state that the late Mr. Bentham, when 

 working up the Orchids for the ' Genera Plantarum,' 

 must, I think, have been misinformed when he states 

 under Miltonia vexillarium, p. 563, that '•fide 

 hortulanorum facile cum Odontoglossis vanis nee cum 

 Miltoniis genus proles hybridus gignunt.' 1 Our ex- 

 perience is the very opposite of this. If. vexillarium 

 crosses readily with the flat-lipped Milton ias and spec- 

 tabilis, although thus far we have failed to raise any 

 progeny from these crosses, but not with true Odon- 

 toglots ; often as it has been attempted, no capsules 



are produced. Thus while our experience in muling 

 amongst Odontoglots goes far to disprove the state- 

 ment I have just quoted, it at the same time confirm- 

 unmistakably Mr. Bentham's view as to the proper 

 generic place of vexillarium and its allies, Roezlii 

 Fhaleenopsis, and Warscewiczii" 



The question of bigeneric hybrids is an important 

 one, and opens a wide field for inquiry, discussion, 

 and experiment. It is less practicable, more un- 

 certain in result, and in short becomes more and 

 more impossible as we progress from the equator 

 towards the poles of relationship in plants. Some 

 are sceptical enough to deny the possibility of pro- 

 ducing a single bigeneric hybrid. Dean Herbert be- 

 lieved that all species capable of intercrossing belonged 

 to the same originally created genus ; and the views 

 of many modern workers in the same field, if they do 

 not exactly coincide, run nearly in the same channel. 

 But, considering that genera are often as artificial 

 and arbitrary as are species, it is simply impossible 

 to lay down a definite law or limit, up to which and 

 beyond which hybridisation cannot be effected. 

 The whole thing depends on the amount of differen- 

 tiation in the sexual or reproductive elements. 

 Dean Herbert himself (and Darwin had a similar 

 experience) found within the limits of the same 

 genus [Grinum for instance) a scale of productiveness 

 amongst intercrossed species, ranging from perfect 

 fertility to perfect sterility. The same results accrue 

 in the crossing of varieties in some instances, and 

 individuals or the* di-tri-morphic forms of species 

 frequently present the same or greater unwillingness 

 to interbreed than do forms which we are bound to 

 recognise as good species if we are to retain the latter 

 term in classification at all. 



Thus we may safely conclude that genera, species, 

 and varieties merely differ in degree, not in kind ; 

 that our delimitation of them, in the truest sense of 

 the word, is artificial, arbitrary and of convenience, 

 and that nature lays down no hard and fast lines, 

 such as the botanist or naturalist would fain concoct 

 for their classification purposes. 



The reputed bigeneric hybrids are few, and some 

 of them may be reviewed for the purpose of defining 

 what is meant by the term. Scricobonia Penrhosiensis 

 was obtained by crossing Libonid fioribunda with 

 Sericographis Ghiesbreghtiana, producing a plant very 

 much dwarfed in stature, with feeble diffuse branches 

 and larger flowers than the female parent, with the 

 colour of the male. 



A batch of seedlings have recently been raised 

 between Cyrtanthus sanguineus fiammeus and Vallota 

 purpurea. The latter is the pollen parent, and the 

 mule has foliage similar to it. The flowers have 

 the bent tube of the Cyrtanthus, and spreading 

 segments as in the male, while the colour is variable 



