JUNE, 1910.] THE ORCHID REVIEW. 163 
a cup-shaped: organ, which has the remarkable property of closing up at 
certain times of day or night, enclosing the very small petals and lip. The 
flowers are green, white, or purple, and the period of closing varies much in 
different species. The genus has a similar range to Pleurothallis, and 
about 200 species are known, a few being in cultivation. Physosiphon is a 
small genus differing from Stelis in having the sepals united into a tube at 
the base and spreading above. P. Loddigesii is well-known in gardens, but 
the rarer P. Lindleyi is a much more showy plant. Lepanthes differs from 
Stelis in habit, and in the united sepals not having the property of closing 
up periodically, while the petals and lip are also different. Over fifty 
species are known. 
Masdevallia is a very large and well-known genus, containing some 200 
species, and a good number are very popular garden plants. They have a 
dwarf tufted habit, owing to the suppression of the secondary stems, and 
the flowers are usually solitary, but in a few species racemose. The sepals 
are united at the base into a tube, and prolonged into tails of various lengths 
above, the small petals, lip, and column being included within the tube. 
The flowers vary greatly in size, shape, and colour, from green to yellow, 
white, rose, crimson, and scarlet, and often variously spotted or striped. 
In the M. Chimera group the tube is more open and the lip variously 
saccate, while in M. triaristella and its allies the tails of the lower sepals 
are lateral. In M. muscosa and M. xipheres the lip is elongated, and has 
the remarkable property of closing up when a little tubercule on its face is 
touched, imprisoning the visiting insect in a kind of trap, from which 
it can only escape by crawling past the anther, and thus removing the 
pollinia to fertilise the next flower visited. It also closes normally at night. 
Scaphosepalum is a small genus closely resembling Masdevallia in 
habit, but differing in having the diverging lateral sepals not united to the 
dorsal one into a tube. Cryptophoranthus is quite anomalous, having the 
sepals completely united at the base and apex, the only opening into the 
flower being at the sides where the dorsal and lateral sepals do not quite 
meet, leaving two small lateral openings, hence the term ‘‘ window-bearing 
Orchids.” Nothing is known of the insects which visit the flowers, but 
this remarkable arrangement is evidently connected with the economy of 
fertilisation. About a dozen species are known. All the preceding genera 
have two pollinia with short or minute caudicles. 
Restrepia differs in having four pollinia, and also in floral structure, the 
lateral sepals being united into a broad body, situated behind the lip, while 
the dorsal sepal and petals are narrow, elongated, and more or less antenna- 
like. There are some 20 species, several of which are well-known in culti- 
vation. Brachionidium is a closely allied Colombian and West Indian 
genus, having caudate sepals and petals. About six species have been 
