May, 1913-] THE ORCHID REVIEW. 147 
facies of E. elongatum, but flowers of a peculiar shade of scarlet. A second: 
note speaks of E. elongatum, ‘its stems varying in height from one to: 
eight feet, its verbena-like clusters of flowers varying in colour of different 
plants, some pale yellow, some fawn colour, many pure rich pink, dark. 
purple, and even mauve.” ,This extreme variability is curious, and suggests 
that more than one species may have been confused together. 
As to the reason why these plants find a congenial home in ant’s nests- 
a note by Rodway in the case of Oncidium altissimum is suggestive. 
After giving a graphic account of an experience in obtaining this plant (see 
O.R., iii. p. 40), he remarks: “ On the fork of a tree the Orchid had found 
a congenial habitat, where it grew and flourished for years, developing a 
great mass of roots to be occupied by the immense horde of ants, who, in 
return for house accommodation, undertook to keep off the enemies of the: 
Orchid, of which the cockroach was one of the most inveterate. . . + + 
Is not this one of the reasons why the ants are so ready to take up their 
abode among the Orchid roots? Where its food was to be found the 
cockroach would certainly come, and the ant as certainly find its prey.” 
The benefit may be mutual, and-we would suggest that the roots of the 
Orchid may provide a suitable nesting place for the ants, as is certainly the 
case with Schomburgkia and Diacrium. 
The history of Epidendrum fulgens has already been given (O.R., v. p- 
264), and it may be added that Mr. Sander’s note supplies a new locality 
for the species, which was already known from the adjacent island of 
Trinidad, as well as from Guiana and Brazil. E. xanthinum was originally 
described from Brazil, and so far as I can find has not previously been. 
recorded from the West Indies. R. A. R 
THE BASIS OF MENDELISM.—Unit-characters are not things in them- 
selves distinct and separate from the organ concerned ; each is a quantitative: 
variation plus or minus in some one character possessed by the organism. 
Each- quantitative condition of a character tends to persist from cell- 
generation to cell-generation. When two quantitatively unlike conditions 
of a character are brought together in a fertilised egg, they tend to keep 
their distinctness in subsequent cell-generations and to segregate into 
different gametes at reproduction, .e., they Mendelize. Only by figure of 
speech are we justified in recognising a unit difference between them. That 
difference might equally well be half as great as it is, or a quarter as great, 
or a thousandth part as great. A mono-hybrid ratio would result equally in 
each case upon crossing the two quantitatively different stages. It is the 
Substantial integrity of a quantitative variation from cell-generation to 
cell-generation that constitutes the basis of Mendelism. All else is 
imaginary.—Pror. W. E. CASTLE. 
