Desmodium rotundifolium

Desmodium rotundifolium
Photo by John R. Gwaltney, Southeastern Flora.com
Scientific classification
Kingdom:	Plantae
Division:	Magnoliophyta - Flowering plants
Class:	Magnoliopsida – Dicotyledons
Order:	Fabales
Family:	Fabaceae ⁄ Leguminosae
Genus:	Desmodium
Species:	D. rotundifolium
Binomial name
Desmodium rotundifolium DC.
Natural range of Desmodium rotundifolium from USDA NRCS Plants Database.

Common name: Roundleaf Tick-trefoil

Taxonomic notes

Synonym: Meibomia michauxii Vail

Description

Flowers may be blue or light purple in northern states. In southern areas, fresh corollas are rosy pink, then fading into a whitish color with age. Creeping and trailing habit and prostrate.

Generally, for Desmodium genus, they are "annual or perennial herbs, shrubs or small trees. Leaves 1-5 foliolate, pinnately 3-foliolate in ours or rarely the uppermost or lowermost 1-foliolate; leaflets entire, usually stipellate; stipules caduceus to persistent, ovate to subulate, foliaceous to setaceous, often striate. Inflorescence terminal and from the upper axils, paniculate or occasionally racemose; pedicel of each papilionaceous flower subtended by a secondary bract or bractlet, the cluster of 1-few flowers subtended by a primary bract. Calyx slightly to conspicuously 2-lipped, the upper lip scarcely bifid, the lower lip 3-dentate; petals pink, roseate, purple, bluish or white; stamens monadelphous or more commonly diadelphous and then 9 and 1. Legume a stipitate loment, the segments 2-many or rarely solitary, usually flattened and densely uncinated-pubescent, separating into 1-seeded, indehiscent segments."

Specifically, for D. rotundifolium species, they are "perennial with trailing, densely villous or very rarely glabrate stems 0.5-1.5 m long. Terminal leaflets suborbicular to widely rhombic or obovate, 3-7 cm long, densely appressed to spreading pilose on both surfaces; stipules persistent, ovate, obliquely and widely clasping at base, 8-12 mm long; stipels usually persistent. Inflorescences typically axillary, occasionally terminal, racemose to paniculate; pedicels 6-13 mm long. Calyx sparsely pilose to puberulent; petals purple, 8-10 mm long; stamens diadelphous. Loment of (3) 4-6 segments, each 5-7 mm long, 4-5 broad, both sutures and sides densely uncinlate, both margins about equally indented; stipe 2.5-5 mm long, mostly included within calyx tube and exceeded by stamina remnants."

Distribution

D. rotundifolium is native to the United States from Vermont and Massachusetts west to south Michigan, and south to northeast Florida and the panhandle, Louisiana, and Missouri.

Ecology

Habitat

It is found in mixed hardwoods including pines, oaks, and hickories. It is also found in lightly wooded hillsides, dry glacial drift, and open woods. It requires shaded areas. It is associated with drying sandy loam soil types.

Associated species include Desmodium lineatum, Desmodium ochroleucum, Rhynchosia difformis, Smilax pumila, Rhus aromatica.

Phenology

This species generally flowers from June to August and fruits from August to October. D. rotundifolium has been observed flowering in April and from August through October and has been seen fruiting in September.

Fire ecology

It becomes more robust in response to fire.

Use by animals

The leaves are browsed by deer. The seeds are consumed by bobwhite quail, turkey, and the ruffled Grouse. The plant is a larval host for the Variegated Frittilary butterfly (Euptoieta claudia) and the Southern Cloudywing (Thorybes bathyllus).