XXIV. HISTORY OF ORCHID HYBRIDISATION. 
P. longifolium and P. Schlimu, and yielding respectively P. x Ainsworthi 
(calurum), and P. cardinale, may be mentioned as two familiar examples. In 
each case they exhibit a partial return to the characters of the original 
species. One of them has been carried further, for P. xX cardinale has been 
re-crossed with P. Schlimii, yielding P. x Ada (see p. 226), in which P. 
Schlimii is represented three times over, thus giving seven-eighths of that 
species and only one-eighth P. longifolium. Ina similar way Dendrobium 
x Ainsworthii has been re-crossed with D. « nobile, yielding D. x Rubens, 
and with D. aureum, yielding D. x Gem; while Leeliocattleya xX 
Schilleriana has been re-crossed with Cattleya intermedia, yielding L.-c. x 
Zampa, and with Lelia purpurata yielding L.-c. x Horniana. There are 
even smaller degrees of difference. For example, Phragmopedilum x 
Sedenii has been crossed with both P. x Ainsworthii and P. x cardinale, 
and although the parents are themselves separated by only a fractional 
difference (one eighth) the respective hybrids have received separate names. 
We have left them as P. X Lemoinierianum and P. x Rosy-Gem, but it 
will be seen that the interval separating the original P. longifolium and P. 
Schlimii has been almost filled up by a series of slightly differing inter- 
mediate forms, involving a very difficult question of nomenclature. 
SECONDARY HyYBrips COMBINING THREE SPECIES may result from the 
intercrossing of primary hybrids with a third species, as in the case of 
Leliocattleya Xx fausta, Just mentioned, or from the union of primary 
hybrids that have one parent in common, as in the variable Paphiopedilum 
< Charlesianum, whose parents, P. x Leeanum and P. & nitens, are both 
partly derived from P. insigne. | Combinations of three species may also be 
formed by crosses of increased complexity. It is among hybrids formed by 
the union of three distinct species that the remarkably wide range of 
variation observed among secondary hybrids is first met with. Paphio- 
pedilum x aureum and P. * Hera may be mentioned as two of the most 
familiar examples, but many others could be enumerated. 
HYBRIDS COMBINING FOUR SPECIES result from the intercrossing of 
primary hybrids whose original parents are all different ; also from more 
complex crosses. For example Paphiopedilum > Harri-Leeanum was 
derived from P. X Harrisianum and P. X Leeanum, and thus is composed of 
equal parts of P. barbatum, villosum, insigne and P. Spicerianum, but the 
same four species were combined when P. Spicerianum and P. * cenanthum 
were united to form P. & Figaro, though the proportions are different. In 
this the amount of P. Spicerianum blood is doubled, while that of P. 
barbatum and P. villosum is reduced by one-half. Again, in P. x 
Brunianum, raised from P. X Leeanum and P. xX cenanthum, the same 
four species appear, but here we get half P. insigne and a quarter of P. 
Spicerianum, while P. barbatum and P. villosum are represented as in P. x 
