THE ORCHID WORLD. 



79 



bulbs. It is quite natural for many of the 

 leaves to drop off before winter. The tem- 

 perature should be <^radually lowered, a good 

 place being the cool end of the Cattleya house 

 where it may remain for the winter ; very little 

 water will be required. 



Early in the new year, when it can be seen 

 that the flower buds are beginning to show, 

 more moisture at the roots and a higher 

 temperature may be allowed, and the plants 

 may, with advantage, be replaced in their 

 growing situation 



SOME IDEAS ON ORCHID HYBRIDISATION. 



By J. M. BLACK. 

 {Continued from Vol. /., page 278.) 



" The Yellow " in Cattleyas and 

 L/ELIAS. — The " yellow " and albinism in 

 Orchids seem to be closely related, and I 

 cannot just remember an instance among 

 Cattleyas or Laelias where the two are 

 entirely dissociated. In the rare L. pumila 

 alba the yellow has paled off almost into a 

 green, and m C. intermedia alba it is only 

 faintly in evidence, while all shades and 

 densities are present in the throats of the 

 various albinos of the labiata section of 

 Cattleyas, being in these latter usually the 

 most decisive factor in distinguishing one 

 variety from another, as no two are exactl}' 

 the same in this respect, the shade and area 

 covered never exactly corresponding. The 

 yellow may range from tasteless straw-colour 

 to orange, and even be rich in tone like the 

 yoke of an egg, as in the case of a C. 

 Percivaliana alba that I know. There can be 

 no degrees of whiteness in albino Cattleyas, 

 although some whites are clearer than others, 

 but in finely grown plants with well nourished 

 flowers of thick texture one can sometimes 

 almost detect a cream tint, and " creamy- 

 white " is not an unusual expression when 

 describing an albino. It will also be observed 

 that most albino Cattleyas open decidedly 

 creamy in tint, but clear up to pure white as 

 the flowers ripen and become set. The seat 

 of the yellow in albino Cattleyas and Laelias 

 is invariably in the labellum, but normally 

 white ground Odontoglossums, like crispuni 

 and Pescatorei, have in the albino forms 

 occasionally a few yellow spots on the other 

 segments, as, for instance, O. c. xanthotes 

 Charlesworthii and O. Pescatorei xanthotes ; 

 but these spots are erratic and only come 

 out strongly when the plants are well grown. 



Now this yellow, which is constantly found 

 in the albino forms of all Cattleyas and 

 Lslias, e.xists in all the coloured forms as 

 well, and in the same varying degree as 

 regards density and distribution, and on the 

 same narrowly defined area of the throat and 

 front lobe of the labellum. This one quality 

 of yellow colour, then, is common to coloured 

 forms and albinos alike. In Cattleya Mossiae 

 and C. Percivaliana there is in the coloured 

 forms usually more yellow than in C. Gas- 

 kelliana and C. labiata, and in the albinos of 

 these the two former have again usually more 

 yellow than the two latter, which is but 

 consistency. In whatever light we regard the 

 purple pig-ment we must accept this yellow 

 as a fixture which no juggling witli hybrid- 

 isation can remove. 



It might be somewhat of a wild speculation 

 to suggest that probably all Cattleyas and 

 Laelias were yellow once, and the albino form 

 is the nearest approach to a sport back to the 

 primeval colour that they are now able to 

 effect at this distance. That is a proposition 

 that I submit as an explanation of the re- 

 curring appearance of these albinos — and 

 albinos appear all over these two genera — 

 and I also rely on that proposition to point 

 the way to our producing the much sought 

 for self-yellow Cattleya by hybridisation. 

 But accepting my rather far-fetched suppo- 

 sition that the yellow has been ousted from all 

 parts of the perianth except the labellum by 

 the purple pigment, we must recognise the 

 hitter's ascendency, and avoid its introduction, 

 if possible, into the generation of yellow 

 Cattleyas that we propose producing. 



I have pointed out in a previous article how 

 careful one must be when crossing for albinos 



