94 CLASS-BOOK OF BOTANY. 
true epiphyte,* growing in large tuits on tree- trunks or 
rocks, and having only aerial roots, which rot away if buried in 
the soil. Its branching stems are thin, wiry, and polished, 
and bear numerous narrow striated 3-nerved leaves, arranged 
in two rows (distichous). In December or January its pretty 
white or pinkish flowers are produced, on slender pedicels, in 
9- or more-flowered racemes, which spring from the axils of 
ig. 181. Ovary of Dendrobium, 
trans. section (mag.), 
Fig. 180. Flowering branch of * : . 
Dendrobium cunninghamit. Big. 182. Flower of Dendrobium, 
long. section. 
the upper leaves. Note first the inferior ovary, which is 
1-celled, and contains an immense number of minute ovules 
on 8 parietal placentee. Above this is the perianth, made up 
of 6 leaves, while the centre of the flower is occupied: by a 
column shaped somewhat like the letter J. Of the three 
outer perianth-leaves, or sepals, one stands up behind the 
upright part of the column, while the other two are lateral, 
_ and have their bases adnate to its produced part. Of the three 
inner leaves, or petals, two are lateral, while the third faces 
the upright part of the column, This petal is nearly always 
remarkably formed in orchids, and is called the labellum, or 
lip. In the present species it is 3-lobed, the small lateral 
lobes being usually of a bright-crimson colour, while on the 
central lobe is a longitudinal series of 5 yellow plate-like 
ridges. The labellum is jointed on to the tip of the produced 
part of the column, and is easily bent back—e.g., by the 
weight of an insect; but it is sufficiently elastic to spring up 
again when the pressure is removed. When all the perianth- 
leaves have been removed only the column is left, standing on 
the summit of the ovary. The produced portion of this, on 
which the labellum stands, ends in a green glandular swelling, 
at the base of which a drop of nectar is excreted. The up- 
Che! Ca See oo hee ee 
* Gr. ept, upon; phyton, a plant. 
