APRIL, 1918.] THE ORCHID REVIEW. 79 
REVERSION IN ODONTOGLOSSUM PESCATOREI. Ee: 
ea 
HE ground colour of Odontoglossum Pescatorei is normally white, and 
a correspondent some time ago called our attention to the occasional 
appearance of yellow forms among imported plants, and asked if these were 
not something more than mere variations. 
The earliest recorded yellow form that we know of was in 1882, when 
Reichenbach described O. Pescatorei flaveolum (Gard. Chron., 1882, i. p. 
330). He remarked: ‘‘ This isa highly curious variety, with very blunt 
oblong petals. There is some sulphur on all parts of the perigone. It was 
sent by Messrs. Veitch & Sons.” Two years later it was painted by Mr, 
John Day (Orch. Draw., xxxix. t. 31), who remarked: “ This is the only 
yellow O. Pescatorei I have ever seen or heard of. Itis in flower at Messrs. 
J. Veitch & Sons, a small plant with a scape of four flowers as drawn. 
There is nothing else but colour to distinguish it from ordinary varieties. 
The colour is quite accurate when I drew it from the fresh opened flowers, 
but when I saw it a week later much of the yellow had faded out of the 
petals, but the labellum still maintained its colour.’’ The latter may be 
described as primrose yellow, with a slight rosy suffusion in the sepals, and 
the usual red streaks on the side lobes of the lip. 
O. Pescatorei Golden Gem was exhibited at a meeting of the R. H. S. 
in July, 1907, by Messrs. Charlesworth & Co., and we noted it as having 
‘pretty yellow flowers, much resembling O. Pescotorei in shape, though 
we suspect that the colour is due to the influence of O. triumphans” (O. R., 
Xv. p. 246). This was a suggestion that it might be a form of O. excellens. 
There is a clear yellow form of O. excellens, namely O. excellens var. 
luteolum (O.R., iv. p. 248), which flowered in the collection of the late 
Baron Sir H. Schréder. In this the characteristic brown blotches of the 
type are nearly absent, being limited to a few markings on the lip, with a 
single spot on the lateral sepal of one flower of the inflorescence. The 
flowers are sulphur yellow, with a whitish area in the centre of the petals, 
and the usual intermediate shape. 
O. excellens is a natural hybrid from O. Pescatorei and triumphans, and 
if it recrosses with the former we should expect to find reversions showing a 
yellow colour, and any remains of the triumphans character would afford 
conclusive evidence of hybridity. In the absence, however, of the 
characteristic triumphans shape the evidence is not conclusive, and if white- 
ground Odontoglossums wereoriginally derived from yellow, as there are 
grounds for believing, we might have reversion without hybridity. Evidence 
from direct experiment would be interesting. Be A. Be 
