156 MR. R. A. ROLFE ON 
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On Bigeneric Orchid Hybrids. By RoBERT ALLEN ROLFE, 
A.L.S., Assistant in the Herbarium of the Royal Gardens, Kew. 
[Read 5th May, 1887.] 
(Puate IV.) 
Zygocolax x Veitchii, Rolfe*, is a remarkable bigeneric hybrid 
which recently flowered in the Royal Exotie Nursery of Messrs. 
James Veitch and Sons at Chelsea. It was raised by Mr. Seden, 
the well-known hybridist, by crossing Zygopetalum crinitum, 
Lodd., with the pollen of Oolax jugosus, Lindl., the seed having 
been sown in April 1882. The two parents are somewhat diverse in 
structure, as the accompanying Plate IV. will show. In Bentham 
and Hooker’s ‘ Genera Plantarum,’ however, Colax is reduced as 
a synonym of Lycaste, a course which hardly seems warranted by 
the structure of the two; so that for the purpose of the present 
paper I have treated Colaz as a distinct genus. 
The diversity in structure between this genus and Zygopetalum 
renders the occurrence of a hybrid between them a matter of 
considerable interest, especially as hybrids generally are known 
to be more or less intermediate between the two parents. This 
case is no exception to the general rule, as the accompanying 
Plate will show. The flower, in shape, is tolerably intermediate 
between the two parents, the coloration most closely resembling 
that of the seed-parent, and the pollinarium approaching rather 
that of the pollen-parent. 
Being so far intermediate between the two parents, the ques- 
tion arose as to how the plant should be treated in the scheme 
of classification. Several bigeneric hybrids of Orchidaces have 
been artificially produced; and looking for the precedents 
adopted in these cases, I found the information respecting them 
to be very vague, and the nomenclature generally unsatisfactory. 
So that instead of confining my remarks to Zygocolax, I have 
extended the paper so as to include other bigeneric hybrids of the 
Order, and have specially considered the subject in its general 
bearing upon classification. 
The way in which bigeneric hybrids of Orchidaces have hitherto 
been treated (omitting specific details) may be briefly summarized 
as follows, the seed-parent being enumerated in the left-hand 
* Gard. Chron. 1887, pt. 1, p. 765. 
