WILD FLOWERS [54]
it leads its visitors to look for pollen instead of nectar, on the supposition that the club-shaped hairs on the crests are stamens. The wonder is that the intelligent little bees (a species of Andrenidae), which chiefly are its Victims, have not yet learned to boycott it.
"Calopogon," says Professor Robertson, who knows more about the fertilization of American wild flowers by insects than most writers, "is one of a few flowers which move the insect toward the stigma.... There is no expenditure in keeping up a supply of nectar, and the flower, although requiring a smooth insect of a certain size and weight, suffers nothing from the visits of those it cannot utilize. Then, there is no delay caused by the insect waiting to suck; but as soon as it alights it is thrown down against the stigma. This occurs so quickly that, while standing net in hand, I have seen insects effect pollination and escape before I could catch them. So many orchids fasten their pollinia upon the faces and tongues of insects that it is interesting to find one which applies them regularly to the first abdominal segment. Mr. Darwin has observed that absence of hair on the tongues of Lepidoptera (butterflies and moths) and on the faces of Hymenoptera (bees; wasps, etc.) has led to the more usual adaptations, and sparseness of hair has its influence in this case. Species of Augochlora are the only insects on which I found pollinia. These bees are very smooth, depending for ornament on the metallic sheen of their bodies. An Halictus repeatedly pulled down the labella (lips) of flowers from which pollinia had not been removed; and the only reason I can assign for its failure to extract pollinia is that it is more hairy than the Augochlora.
COMMON PERSICARIA, PINK KNOTWEED, or JOINT-WEED; SMARTWEED (Polygonum Pennsylvanicum) Buckwheat family
Flowers - Very small, pink, collected in terminal, dense, narrow, obtuse spikes, 1 to 2 in. long. Calyx pink or greenish, 5-parted, like petals; no corolla; stamens 8 or less; style 2-parted. Stem: 1 to 3 ft. high, simple or branched, often partly red, the joints swollen and sheathed; the branches above, and peduncles glandular. Leaves: Oblong, lance-shaped, entire edged, 2 to 11 in. long, with stout midrib, sharply tapering at tip, rounded into short petioles below. Preferred Habitat - Waste places, roadsides, moist soil. Flowering Season - July-October. Distribution - Nova Scotia to the Gulf of Mexico; westward to Texas and Minnesota.
Everywhere we meet this commonest of plants or some of its similar kin, the erect pink spikes brightening roadsides, rubbish heaps, fields, and waste places, from midsummer to frost. The little flowers, which open without method anywhere on the spike they choose, attract many insects, the smaller bees (Andrena) conspicuous among the host. As the spreading divisions of the perianth make nectar-stealing all too easy for ants and other crawlers that would not come in contact with anthers and stigma where they enter a flower near its base, most buckwheat plants whose blossoms secrete sweets protect themselves from theft by coating the upper stems with glandular hairs that effectually discourage the pilferers. Shortly after fertilization, the little rounded, flat-sided fruit begins to form inside the persistent pink calyx. At any time the spike-like racemes contain more bright pink buds and shining seeds than flowers. Familiarity alone breeds contempt for this plant, that certainly possesses much beauty.
The LADY'S THUMB (P. Persicaria), often a troublesome weed, roams over the whole of North America, except at the extreme north - another illustration of the riotous profusion of European floral immigrants rejoicing in the easier struggle for existence here. Its pink spikes are shorter and less slender than those of the preceding taller, but similar species, and its leaves, which are nearly seated on the stem, have dark triangular or lunar marks near the center in the majority of cases.
An insignificant little plant, found all over our continent, Europe, and Asia, is the
"Calopogon," says Professor Robertson, who knows more about the fertilization of American wild flowers by insects than most writers, "is one of a few flowers which move the insect toward the stigma.... There is no expenditure in keeping up a supply of nectar, and the flower, although requiring a smooth insect of a certain size and weight, suffers nothing from the visits of those it cannot utilize. Then, there is no delay caused by the insect waiting to suck; but as soon as it alights it is thrown down against the stigma. This occurs so quickly that, while standing net in hand, I have seen insects effect pollination and escape before I could catch them. So many orchids fasten their pollinia upon the faces and tongues of insects that it is interesting to find one which applies them regularly to the first abdominal segment. Mr. Darwin has observed that absence of hair on the tongues of Lepidoptera (butterflies and moths) and on the faces of Hymenoptera (bees; wasps, etc.) has led to the more usual adaptations, and sparseness of hair has its influence in this case. Species of Augochlora are the only insects on which I found pollinia. These bees are very smooth, depending for ornament on the metallic sheen of their bodies. An Halictus repeatedly pulled down the labella (lips) of flowers from which pollinia had not been removed; and the only reason I can assign for its failure to extract pollinia is that it is more hairy than the Augochlora.
COMMON PERSICARIA, PINK KNOTWEED, or JOINT-WEED; SMARTWEED (Polygonum Pennsylvanicum) Buckwheat family
Flowers - Very small, pink, collected in terminal, dense, narrow, obtuse spikes, 1 to 2 in. long. Calyx pink or greenish, 5-parted, like petals; no corolla; stamens 8 or less; style 2-parted. Stem: 1 to 3 ft. high, simple or branched, often partly red, the joints swollen and sheathed; the branches above, and peduncles glandular. Leaves: Oblong, lance-shaped, entire edged, 2 to 11 in. long, with stout midrib, sharply tapering at tip, rounded into short petioles below. Preferred Habitat - Waste places, roadsides, moist soil. Flowering Season - July-October. Distribution - Nova Scotia to the Gulf of Mexico; westward to Texas and Minnesota.
Everywhere we meet this commonest of plants or some of its similar kin, the erect pink spikes brightening roadsides, rubbish heaps, fields, and waste places, from midsummer to frost. The little flowers, which open without method anywhere on the spike they choose, attract many insects, the smaller bees (Andrena) conspicuous among the host. As the spreading divisions of the perianth make nectar-stealing all too easy for ants and other crawlers that would not come in contact with anthers and stigma where they enter a flower near its base, most buckwheat plants whose blossoms secrete sweets protect themselves from theft by coating the upper stems with glandular hairs that effectually discourage the pilferers. Shortly after fertilization, the little rounded, flat-sided fruit begins to form inside the persistent pink calyx. At any time the spike-like racemes contain more bright pink buds and shining seeds than flowers. Familiarity alone breeds contempt for this plant, that certainly possesses much beauty.
The LADY'S THUMB (P. Persicaria), often a troublesome weed, roams over the whole of North America, except at the extreme north - another illustration of the riotous profusion of European floral immigrants rejoicing in the easier struggle for existence here. Its pink spikes are shorter and less slender than those of the preceding taller, but similar species, and its leaves, which are nearly seated on the stem, have dark triangular or lunar marks near the center in the majority of cases.
An insignificant little plant, found all over our continent, Europe, and Asia, is the