_Cypripedium acaule_
_Flowers_--Fragrant, solitary, large, showy, drooping from end of scape,
6 to 12 in. high. Sepals lance-shaped, spreading, greenish purple, 2 in.
long or less; petals narrower and longer than sepals. Lip an inflated
sac, often more than 2 in. long, slit down the middle, and folded
inwardly above, pale magenta, veined with darker pink; upper part of
interior crested with long white hairs. Stamens united with style into
unsymmetrical declined column, bearing an anther on either side, and a
dilated triangular petal-like sterile stamen above, arching over the
broad concave stigma. _Leaves:_ 2, from the base; elliptic, thick, 6 to
8 in. long.
_Preferred Habitat--Deep_, rocky, or sandy woods.
_Flowering Season_--May-June.
_Distribution_--Canada southward to North Carolina, westward to
Minnesota and Kentucky.
Because most people cannot forbear picking this exquisite flower that
seems too beautiful to be found outside a millionaire’s hothouse, it is
becoming rarer every year, until the finding of one in the deep forest,
where it must now hide, has become the event of a day’s walk. Once it
was the commonest of the orchids.
“Cross-fertilization,” says Darwin, “results in offspring which vanquish
the offspring of self-fertilization in the struggle for existence.” This
has been the motto of the orchid family for ages. No group of plants has
taken more elaborate precautions against self-pollination or developed
more elaborate and ingenious mechanism to compel insects to transfer
their pollen than this.
The fissure down the front of the Pink Lady’s Slipper is not so wide but
that a bee must use some force to push against its elastic sloping sides
and enter the large banquet chamber where he finds generous
entertainment secreted among the fine white hairs in the upper part.
Presently he has feasted enough. Now one can hear him buzzing about
inside, trying to find a way out of the trap. Toward the two little
gleams of light through apertures at the end of a passage beyond the
nectary hairs he at length finds his way. Narrower and narrower grows
the passage until it would seem as if he could never struggle through;
nor can he until his back has rubbed along the sticky, overhanging
stigma, which is furnished with minute, rigid, sharply pointed papillae,
all directed forward, and placed there for the express purpose of
combing out the pollen he has brought from another flower on his back
or head. The imported pollen having been safely removed, he still has to
struggle on toward freedom through one of the narrow openings, where an
anther almost blocks his way.
As he works outward, this anther, drawn downward on its hinge, plasters
his back with yellow granular pollen as a parting gift, and away he
flies to another lady’s slipper to have it combed out by the sticky
stigma as described above. The smallest bees can squeeze through the
passage without paying toll. To those of the Andrena and Halictus tribe
the flower is evidently best adapted. Sometimes the largest bumblebees,
either unable or unwilling to get out by the legitimate route, bite
their way to liberty. Mutilated sacs are not uncommon. But when unable
to get out by fair means, and too bewildered to escape by foul, the
large bee must sometimes perish miserably in his gorgeous prison.