The genus of True Orchises comprises eighty species, distributed
throughout the temperate zone of the world; while of Habenaria there
are about five hundred species. _Orchis spectabilis_ and _Orchis
rotundifolia_ are found in Vermont. The latter is the rarer, and limited
in its range from northern New England to Greenland. The _Orchis
spectabilis_ ranges from Ontario southward to Georgia. The third species,
_Orchis aristata_, is endemic to the wooded regions of Alaska.
Our common Showy Orchis resembles the Early Spring Orchis (_Orchis
mascula_) of England, which Darwin never tired of praising. The high
organism distinguishes species of this genus as True Orchises. The
origin of this distinction lies in the complex structure of the organs
of fertilization. The stigmatic lobes, or female organs, and the anther
containing the pollinia or male substance in fertilizing, are enclosed
in this genus in a pouch or hooded fold above and within the anterior
portion of the orifice of the spur. In False Orchises, the stigma and
anther are naked, and their glands are exposed. They are also known
as Naked Gland Orchises. The more complex the structure, the more
highly organized becomes the species. _Orchis spectabilis_ displays a
marvellous intelligence in its mechanism for inviting fertilization and
cross-fertilization. The enclosure of the glands within the hooded pouch
protects the pollinia from rains or improper insects.
The moth finds a resting-place on the petaled platform, while he pushes
his tongue and head into the depths of the dainty spur attached to
the flower anteriorly. In doing this he forces his forehead against
the viscid lobes of the stigma, situated in the back, opposite to the
entrance of the spur. In pushing, as he must, to reach the nectar in
the twisting spur, he ruptures the interior membrane of the rostellum
above the orifice containing the pollinia. Each mass of this fertilizing
substance in this species contains viscid disks or handles, fastened
with elastic hair-like caudicles attached to the pollinia. When the
insect ruptures the cellular tissues of the anther, these disks shoot
out of their sockets, and fasten firmly to his head. As he flies away,
he possesses one or two pollinia, unique in their completeness. In
visiting the next spike of the Showy Orchis, he repeats the insertion
of his tongue and forehead in the spur of the nectary. The golden horn
of pollinum thus rubs against the viscid surface of the stigma, and
fertilization and cross-fertilization are brought about. The insect
thus accomplishes all that Nature has designed for the future of the
species, even if only a small portion of the pollinum is absorbed by the
attractive surface of the stigma. One mass fastened to the head of a moth
would, in this manner, fertilize several flowers.
According to Darwin, orchids with short-spurred nectaries are fertilized
by bees and flies; while those with long spurs are visited by moths and
butterflies with long proboscides.
Public-domain text, read in full here on John Shaqi.
Reviews
Reviews
No reviews yet
Be the first to share your thoughts on this work.
Join the Discussion
Join the discussion
Sign in to leave a comment or review.
Sign InorCreate an account