56 THE ORCHID REVIEW. 
ARE STELIS FLOWERS IRRITABLE ? 
About seventy-five years ago, when figuring the Jamaican Stelis 
ophioglossoides in their Botanical Cabinet (vol. v. t. 442), Messrs. Loddiges 
remarked :—‘‘ It is a minute and curious plant; its flowers last a long 
while, during the months of August and September ; they open and shut at 
various times, and that so suddenly, that we found considerable difficulty in 
making our drawing, attempting it several times, when they closed directly, 
as soon as removed or touched.” ‘The statement has been repeated on 
various occasions, though so far as I know without confirmation, and I have 
never been able to detect anything of the kind among the various species in 
cultivation. Mr. George Syme published some interesting observations on 
the two Jamaican species, in 1880 (Gard. Chron., 1880, ii. p. 819), which are 
here reproduced :— : 
“‘ The flowers of S. ophioglossoides and S. micrantha, both natives of the 
higher mountains of Jamaica, though not irritable, are sensitive in a some- 
what passive degree, inasmuch as their opening and closing is entirely 
regulated by the density of the enveloping atmosphere. Under cultivation 
in the garden here at a few hundred feet above sea level during dry, sunny 
days, their flowers are persistently closed; but should the sky become 
clouded with a tendency to rain they immediately relax, and should rain fall 
they are shortly in full blossom. It is quite different with them at night. 
The nights here are generally damp and dewy, and the flowers of our two 
Orchids open with the falling of the dew a dusk, and close again at sunrise 
or shortly after, when the dew is evaporated. I have shut up flowering 
plants of both species in a box during the day to ascertain what effect the 
darkness or absence of light might have on the movements of the flowers, 
but at the close of three hours the deltoid sepals were still closed. Thus, 
here they might be styled night-blooming, and they virtually are so; but 
they are far removed from home and the associated conditions of life to 
which they have so very long been educated. Naturally they affect the 
trees in dark, shady forests, at elevations of from 4,000 to 7,000 feet, where 
they are almost continually enveloped in fog or pelted with torrents of rain, 
and consequently at the proper season their flowers are almost constantly 
open by day as well as night.” 
My own observations point in the same direction, though with some 
differences in detail, for the various species in cultivation do not all behave 
in the same way, though they all close at some time of the day. For 
example, a green flowered and a purple flowered species will stand side by 
side in the same house, and one will have the flowers open but the other 
closed at a certain time of day, while later the conditions may be reversed. 
My impression is that the opening and closing of the flowers is entirely 
