Flowers Fertilised by Birds 1OI 
nectaries; and in tropical America not only bees, moths, and 
other large insects carry the pollen from one flower to another, 
but many flowers, like the Marcgravia, are specially adapted 
to secure the aid of small birds, particularly humming-birds, 
for this purpose. Amongst these, the “‘ palosabre,” a species 
of Erythrina, a small tree, bearing red flowers, that grew in 
this valley, near the brook, often drew my attention. The 
tree blooms in February, and is at the time leafless, so that the 
large red flowers are seen from a great distance. . Each 
flower consists of a single long, rather fleshy petal, doubled 
over, flattened, and closed, excepting a small opening on one 
edge, where the stamens protrude. Only minute insects can 
find access to the flower, which secretes at the base a honey- 
like fluid. Two long-billed humming-birds frequent it; one 
(Heliomaster pallidiceps, Gould), which I have already 
mentioned, is rather rare; the other (Phethornts longirosiris, 
—S 
FLOWER OF PALOSABRE 
De Latt.) might be seen at any time when the tree was in 
bloom, by watching near it for a few minutes. It is mottled 
brown above, pale below, and the two middle tail feathers are 
much longer than the others. The bill is very long and curved, 
enabling the bird easily to probe the long flower, and with its 
extensile cleft tongue pick up the minute insects from the 
bottom of the tube, where they are caught as if in a trap, 
their only way of exit being closed by the bill of the bird. 
Whilst the bird is probing the flower, the pollen of the 
stamens is rubbed in to the lower part of its head, and thus 
carried from one flower to fecundate another. The bottom 
of the flower is covered externally with a thick, fleshy calyx 
—an effectual guard against the attempts of bees or wasps 
to break through to get at the honey. Humming-birds feed 
on minute insects, and the honey would only be wasted if 
larger ones could gain access to it, but in the flower of the 
palosabre this contingency is simply and completely guarded 
against. 
Many flowers have contrivances for preventing useless 
