(Apocynum cannabinum) Dogbane family
Flowers - Greenish white, about 1/4 in. across, on short
pedicels, in dense clusters at ends of branches and from the
axils. Calyx of 5 segments; corolla nearly erect, bell-shaped,
5-lobed, with 5 small triangular appendages alternating with the
stamens
within its tube. Stem: 1 to 4 ft. high, branching,
smooth, often dull reddish, from a deep, vertical root. Leaves:
Opposite, entire, 2 to 6 in. long, mostly oblong, abruptly
pointed, variable. Fruit: A pair of slender pods, the numerous
seeds tipped with tufts of hairs.
Preferred Habitat - Gravelly soil, banks of streams, low fields.
Flowering Season - June-August.
Distribution - Almost throughout the United States and British
Possessions.
Instead of setting a trap to catch flies and hold them by the
tongue in a vise-like grip until death alone releases them, as
its heartless sister the spreading dogbane does (q.v.), this
awkward, rank herb lifts clusters of smaller, less conspicuous,
but innocent, flowers, with nectar secreted in rather shallow
receptacles, that even short-tongued insects may feast without
harm. Honey and mining bees, among others; wasps and flies in
variety, and great numbers of the spangled fritillary (Argynnis
cybele) and the banded hair-streak (Thecla calanus) among the
butterfly tribe; destructive bugs and beetles attracted by the
white color, a faint odor, and liberal entertainment, may be seen
about the clusters. Many visitors are useless pilferers, no
doubt; but certainly the bees which depart with pollen masses
cemented to their lips or tongues, to leave them in the stigmatic
cavities of the next blossoms their heads enter, pay a fair price
for all they get.
>From the fact that Indians used to substitute this very common
plant's tough fiber for hemp in making their fishnets, mats,
baskets, and clothing, came its popular name; and from their use
of the juices to poison mangy old dogs about their camps, its
scientific one.
WHORLED or GREEN-FLOWERED MILKWEED
(Asclepias verticillata) Milkweed family
Flowers - White or greenish, on short pedicels, in several small
terminal clusters. Calyx inferior; corolla deeply 5-parted, the
oblong segments turned back; a 5-parted, erect crown of hooded
nectaries between them and the stamens, each shorter than the
incurved horn within. Stem: 1 to 2 1/2 ft. tall, simple or
sparingly branched, hairy, leafy to summit, containing milky
juice. Leaves: In upright groups, very narrow, almost
thread-like, from 3 to 7 in each whorl. Fruit: 2 smooth, narrow,
spindle-shaped, upright pods, the seeds attached to silky fluff;
1 pod usually abortive.
Preferred Habitat - Dry fields, hills, uplands.
Flowering Season - July-September.
Distribution - Maine and far westward, south to Florida and
Mexico.
In describing the common milkweed (q.v.), so many statements were
made that apply quite as truly to this far daintier and more
ethereal species, the reader is referred back to the pink and
magenta section. Compared with some of its rank-growing, heavy
relatives, how exquisite is this little denizen of the uplands,
with its whorls of needle-like leaves set at intervals along a
slender swaying stem! The entire plant, with its delicate foliage
and greenish-white umbels of flowers, rather suggests a member of
the carrot tribe; and much the same class of small-sized,
short-tongued visitors come to seek its accessible nectar as we
find about the parsnips, for example. When little bees alight -
and these are the truest benefactors, however frequently larger
bees, wasps, flies, and even the almost useless butterflies come
around - their feet slip about within the low crown to find a
secure lodging. As they rise to fly away after sucking, the
pollen masses which have attached themselves to the hairs on the
lower part of their legs are drawn out, to be transferred to
other blossoms, perhaps today, perhaps not for a fortnight.
Annoying as they may be, it is very rarely, indeed, that an
insect can rid itself of the pollen masses carried from either
orchids or milkweeds, except by the method Nature intended; and
it is not until the long-suffering bee is outrageously loaded
that he attains his greatest usefulness to milkweed blossoms. "Of
ninety-two specimens bearing corpuscula of Asclepias
verticillata," says Professor Robertson, "eighty-eight have them
on hairs alone, and four on the hairs and claws." And again: "As
far as the mere application of pollen to an insect is concerned,
a flower with loose pollen has the advantage. But the advantage
is on the side of Asclepias after the insect is loaded with it.
It is only a general rule that insects keep to flowers of a
particular species on their honey and pollen gathering
expeditions. If a bee dusted with loose pollen visits flowers of
another species, it will not long retain pollen in sufficient
quantity to effectually fertilize flowers of the original
species. On the other hand, if an insect returns at any time
during the day, or even after a few days, to the species of
Asclepias from which it got a load of pollinia, it may bring with
it all or most of the pollinia which it has carried from the
first plants visited. The firmness with which the pollinia keep
their hold on the insect is one of the best adaptations for
cross-fertilization."
Ants, the worst pilferers of nectar extant, find the hairy stem
of the whorled milkweed, as well as its sticky juice, most
discouraging, if not fatal, obstacles to climbing. How daintily
the goldfinch picks at the milkweed pods and sets adrift the
seeds attached to silky aeronautic fluff!
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Next: WILD POTATOVINE MANOFTHEEARTH MECHAMECK
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