Wild Flowers Part 38

These leaves are smooth and green above, silvery on the under side, with fine white hairs, adapted for protection from excessive sunlight and too rapid transpiration of precious moisture. They entirely conceal the sensitive epidermis from which they grow.

YELLOW AVENS; FIELD AVENS (Geum strictum) Rose family

Flowers - Golden yellow, otherwise much resembling the lower growing white avens (q.v.).

Preferred Habitat - Low ground, moist meadows, swamps.

Flowering Season - June-August.

Distribution - Pennsylvania, Missouri, and Arizona, far northward.

After the marsh marigolds have withdrawn their brightness from low-lying meadows, blossoms of yellow avens twinkle in their stead. In autumn the jointed, barbed styles, protruding from the seed cl.u.s.ters, steal a ride by the same successful method of travel to new colonizing ground adopted by burdocks, goose-gra.s.s, tick-trefoils (q.v.), agrimony, and a score of other "tramps of the vegetable world."

TALL or HAIRY AGRIMONY (Agrimonia hirsuta; Eupatoria of Gray) Rose family

Flowers - Yellow, small, 5-parted, in narrow, spike-like racemes.

Stem: Usua11y 3 to 4 ft. tall, sometimes less or more clothed, with long, soft hairs. Leaves: Large, thin, bright green, compounded of (mostly) 7 princ.i.p.al oblong, coa.r.s.ely saw-edged leaflets, with pairs of tiny leaflets between.

Preferred Habitat - Woods, thickets, edges of fields.

Flowering Season - June-August.

Distribution - North Carolina, westward to California, and far north.

Quite a different species, not found in this country, is the common European Agrimony - A. Eupatoria of Linnaeus - which figures so prominently in the writings of medieval herbalists as a cure-all. Slender spires of green fruit below and yellow flowers above curve and bend at the borders of woodlands here apparently for no better reason than to enjoy life. Very few insects visit them, owing to the absence of nectar - certainly not the highly specialized and intelligent "Humble-Bee," to whom Emerson addressed the lines:

"Succory to match the sky, Columbine with horn of honey, Scented fern and agrimony, Clover, catch-fly, adder's-tongue, And brier-roses, dwelt among."

It is true the b.u.mblebee may dwell among almost any flowers, but he has decided preferences for such showy ones as have adapted themselves to please his love of certain colors (not yellow), or have secreted nectar so deeply hidden from the mob that his long tongue may find plenty preserved when he calls. Occasional visitors alighting on the agrimony for pollen may distribute some, but the little blossoms chiefly fertilize themselves. When crushed they give forth a faint, pleasant odor. Pretty, nodding seed urns, encircled with a rim of hooks, grapple the clothing of man or beast pa.s.sing their way, in the hope of dropping off in a suitable place to found another colony.

SENSITIVE PEA; WILD or SMALL-FLOWERED SENSITIVE PLANT (Ca.s.sia nict.i.tans) Senna family

Flowers - Yellow, regular, 5-parted, about 1/4 in. across; 2 or 3 together in the axils. Stem: Weak, 6 to 15 in. tall, branching, leafy. Leaves: Alternate, sensitive, compounded of 12 to 44 small, narrowly oblong leaflets; a cup-shaped gland below lowest pair; stipules persistent. Fruit: A pod, an inch long or more, containing numerous seeds.

Preferred Habitat - Dry fields, sandy wasteland, roadsides.

Flowering Season - July-October.

Distribution - New England westward to Indiana, south to Georgia and Texas.

How many of us ever pause to test the sensitiveness of this exquisite foliage that borders the roadsides, and in appearance is almost identical with the South American sensitive plant's, so commonly cultivated in hothouses here? Failing to see its fine little leaflets fold together instantly when brushed with the hand, as they do in the tropical species (Mimosa pudica), many pa.s.s on, concluding its t.i.tle a misnomer. By simply touching the leaves, however roughly, only a tardy and slight movement follows. A sharp blow produces quicker effect, while if the whole plant be shaken by forcibly snapping the stem with the finger, all the leaves will be strongly affected; their sensitiveness being apparently more aroused by vibration through jarring than by contact with foreign bodies. The leaves, which ordinarily spread out flat, partly close in bright suns.h.i.+ne and "go to sleep" at night, not to expose their sensitive upper surfaces to fierce heat in the first case, and to cold by radiation in the second. "Lifeless things may be moved or acted on," says Asa Gray; "living beings move and act - plants less conspicuously, but no less really than animals. In sharing the mysterious gift of life they share some of its simpler powers."

The PARTRIDGE PEA or LARGE-FLOWERED SENSITIVE PLANT (C.

Chamaecrista) likewise goes to sleep; the ten to fifteen pairs of leaflets which, with a terminal one, make up each pinnate leaf, slowly turning their outer edges uppermost after sunset, and overlapping as they flatten themselves against their common stem until the entire aspect of the plant is changed. By day the expanded foliage is feathery, fine, acacia-like; at night the bushy, branching, spreading plant, that measures only a foot or two high, appears to produce nothing but pods. These leaves respond slowly to vibration, just as the sensitive pea's do. In spite of their names, neither produces the b.u.t.terfly-shaped (papilionaceous) blossom of true peas. The partridge pea bears from two to four showy flowers together, each measuring an inch or more across, on a slender pedicel from the axils. It fully expands only four of its five bright yellow petals; they are somewhat unequal in size, the upper ones, with touches of red at the base, as pathfinders, not, however, as nectar-guides, since no sweets are secreted here. Curiously enough, both right and left hand flowers are found upon the same plant; that is to say, the sickle-shaped pistil turns either to the right or the left.

One lateral petal, instead of being flexible and spread like the rest, stands so stiffly erect and incurved that it commonly breaks on being bent back. Why? The pistil, it will be noticed, points away from the ten long black anthers. Obviously, then, the flower cannot fertilize itself. Its benefactors are b.u.mblebee females and workers out after pollen. Cup-shaped nectaries ("extra nuptial") are situated on the upper side and near the base of the leaf stalks on these ca.s.sia plants, where they can have no direct influence on the fertilization of the blossoms.

Apparently, they are free lunch-counters, kept open out of pure charity. Landing upon the long black anthers with pores in their tips to let out the pollen, the b.u.mblebees "seize them between their mandibles, says Professor Robertson, "and stroke them downward with a sort of milking motion. The pollen...falls either directly upon the bee or upon the erect lateral petal which is pressed close against the bee's side. In this way the side of the bee which is next to the incurved petal receives the most pollen.... A bee visiting a left-hand flower receives pollen upon the right side, and then flying to a right-hand flower, strikes the same side against the stigma." When we find circular holes in these petals we may know the leaf-cutter or upholsterer bee (Megachile brevis) has been at work collecting roofs for her nurseries (see Hairy Ruellia). The partridge pea, which has a more westerly range than the sensitive pea's, extends it southward even to Bolivia. Game birds, migrants and rovers, which feed upon the seeds, have of course helped in their wider distribution. The plant blooms from July to September.

WILD or AMERICAN SENNA (Ca.s.sia Marylandica) Senna family

Flowers - Yellow, about 3/4 in. broad, numerous, in short axillary cl.u.s.ters on the upper part of plant. Calyx of 5 oblong lobes; 5 petals, 3 forming an upper lip, 2 a lower one; 10 stamens of 3 different kinds; 1 pistil. Stem: 3 to 8 ft. high, little branched. Leaves: Alternate, pinnately compounded of 6 to 10 pairs of oblong leaflets. Fruit: A narrow, flat curving pod, 3 to 4 in. long.

Preferred Habitat - Alluvial or moist, rich soil, swamps, roadsides.

Flowering Season - July-August.

Distribution - New England, westward to Nebraska, south to the Gulf States.

Whoever has seen certain Long Island roadsides bordered with wild senna, the brilliant flower cl.u.s.ters contrasted with the deep green of the beautiful foliage, knows that no effect produced by art along the drives of public park or private garden can match these country lanes in simple charm. b.u.mblebees, buzzing about the blossoms, may be observed "milking" the anthers just as they do those of the partridge pea. No red spots on any of these petals guide the visitors, as in the previous species, however; for do not the three small, dark stamens, which are reduced to mere scales, answer every purpose as pathfinders here? The stigma, turned sometimes to the right, sometimes to the left, strikes the bee on the side; the senna being what Delpino, the Italian botanist, calls a pleurotribe flower.

While leaves of certain African and East Indian species of senna are most valued for their medicinal properties, those of this plant are largely collected in the Middle and Southern States as a subst.i.tute. Caterpillars of several sulphur b.u.t.terflies, which live exclusively on ca.s.sia foliage, appear to feel no evil effects from overdoses.

WILD INDIGO; YELLOW or INDIGO BROOM; HORSEFLY-WEED (Baptisia tinctoria) Pea family

Flowers - Bright yellow, papilionaceous, about 1/2 in. long, on short pedicels, in numerous but few flowered terminal racemes.

Calyx light green, 4 or 5-toothed; corolla of 5 oblong petals, the standard erect, the keel enclosing 10 incurved stamens and pistil. Stem: Smooth, branched, 2 to 4 ft. high. Leaves: Compounded of 3 ovate leaflets. Fruit: A many-seeded round or egg-shaped pod tipped with the awl-shaped style.

Preferred Habitat - Dry, sandy soil.

Flowering Season - June-September.

Distribution - Maine and Minnesota to the Gulf States.

Dark grayish green, clover-like leaves, and small, bright yellow flowers growing in loose cl.u.s.ters at the ends of the branches of a bushy little plant, are so commonly met with they need little description. A relative, the true indigo-bearer, a native of Asia, once commonly grown in the Southern States when slavery made compet.i.tion with Oriental labor possible, has locally escaped and become naturalized. But the false species, although, as Dr. Gray says, it yields "a poor sort of indigo," yields a most valuable medicine employed by the homeopathists in malarial fevers. The plant turns black in drying. As in the case of other papilionaceous blossoms, bees are the visitors best adapted to fertilize the flowers. When we see the little, sleepy, dusky-winged b.u.t.terfly (Thanaos brizo) around the plant we may know she is there only to lay eggs, that the larvae and caterpillars may find their favorite food at hand on waking into life.

RATTLE-BOX (Crotalaria sagittalis) Pea family

Flowers - Yellow, 1/2 in. long or less, usually only 2 or 3 on a long peduncle. Calyx 5-toothed, slightly 2-lipped; corolla papilionaceous. Stem: 3 to 10 in. high, weak, hairy. Leaves: Alternate, simple, oval to lance-shaped; stipules arrow-shaped above and running along stem. Fruit: An inflated oblong pod 1 in, long, blackish, seedy.

Preferred Habitat - Dry, sandy, open situations.

Flowering Season - June-September.

Distribution - New England and Minnesota to the Gulf of Mexico.

These insignificant little yellow flowers attract scant notice from human observers accustomed to a.s.sociate their generic name with some particularly beautiful relatives from the West Indies grown in hothouses here. But did not small bees alight on the keel and depress it, as in the lupine, next of kin (q.v.) there might be no seeds to rattle in the dark inflated pods that so delight children. (Krotalon = a castanet.)

YELLOW SWEET CLOVER; YELLOW MELILOT (Melilotus officinalis) Pea family

Resembling the white sweet clover, except in color. (q.v.)

YELLOW or HOP CLOVER (Trifotium agrarium) Pea family

Flowers - Yellow, scale-like, overlapping in a densely many-flowered oblong head about 1/2 in. long, becoming brown with age. Stem: Ascending, branched, 6 to 18 in. high. Leaves: 3-foliate, very finely toothed.

Preferred Habitat - Waste places, fields, roadsides.

Flowering Season - May-September.

Distribution - Virginia to Iowa, and far northward.

What did the sulphur b.u.t.terflies provide as food for their caterpillar babies before the commonest clovers came over from the Old World to possess the soil? Wherever a trifolium grows, there one is sure to see

"gallow-yellow b.u.t.terflies, Like blooms of lorn primroses blowing loose, when autumn winds arise."

The BLACKSEED HOP CLOVER, BLACK or HOP MEDIC (Medicago lupulina), with even smaller, bright yellow oblong heads which turn black when ripe, lies on the ground, its branches spreading where they leave the root. A native of Europe and Asia, it is now distributed as a common weed throughout our area, for there is scarcely a month in the year when it does not bloom and set seed.

It is still another of the many plants known as the shamrock.

YELLOW WOOD-SORREL; LADY'S SORREL (Oxalis stricta) Wood-sorrel family

Flowers - Golden, fragrant, in long peduncled, small, terminal groups. Calyx of 5 sepals; corolla of 5 petals, usually reddish at base; stamens, 10; 1 pistil with 5 styles; followed by slender pods. Stem: Pale, erect, 3 to 12 in. high, the sap sour. Leaves: Palmately compound, of 3 heart-shaped, clover-like leaflets on long petioles.

Preferred Habitat - Open woodlands, waste or cultivated soil, roadsides.