MISSOURI BOTANICAL GARDEN BULLETIN 143 
brachiata), with its attenuated sepals and petals, is not inap- 
propriately named. 
The common slipper orchid, a member of the genus 
Cypripedium, is perhaps the most commonly known orchid. 
Several tropical species are even more interesting than our 
native varieties, because in these the laces are furnished in 
the form of attenuated petals, measuring, in some cases, three 
feet in length. This is especially true in Cypripediwm 
caudatum. The cricket orchid (Coryanthes macrantha), a 
native of the West Indies, possesses a concave labellum into 
which two glands secrete nectar which drops down and keeps 
the bucket filled. The cow-horn orchid (Schomburgkia 
tibicinis) of Honduras, has hollow and tapering pseudo- 
bulbs which resemble a cow’s horn. The point of particular 
interest, however, is that in Honduras certain ants make 
their homes in these hollow stems, entering them by means 
of an opening provided near the base. It has been observed 
that the specimen in the Garden collection is at times 
- inhabited by the small black ants which frequent green- 
houses and on several occasions, when the plant has been 
disturbed, the ants have been seen busy carrying their eggs 
out from the base of the pseudo-bulb. 
Pollination. Orchids, with few exceptions, rely on insects 
for their pollination. The pollen is not “paar as is that 
of a lily, and, consequently, cannot be blown about by the 
wind to other flowers. On the contrary, it is produced in 
several compact masses, each attached separately by a 
caudicle to a central viscid disc. These masses are enclosed 
by a pollen cap each mass having a separate chamber. The 
llen may be removed by raising the pollen cap attached 
y the rostellum or beak-like appendage; the latter is readily 
seen in the dove orchid, or the bird’s bill orchid, the rostellum 
- jn both cases representing the bill or beak. 
The particular insect which effects pollination in the dif- 
ferent species varies with the flower, owing to the peculiar 
shapes and modifications of the third petal or lip. The 
latter is exceedingly variable, many of the striking differ- 
ences between orchid flowers being due to variations and 
modifications of this part. In Bulbophyllum fuscum, the 
lip is tongue shaped and only about one-fifth of an inch long, 
whereas in Bulbophyllum barbigerum the #4 resembles a 
globular brush almost an inch long, the delicate parts of 
which are set in motion by the slightest air currents. In 
species of Cattleya the lip appears as a large funnel shaped 
appendage encircling the stamens and pistils, the former 
frequently measuring several inches in length. In Cory- 
