Diodia virginiana L.

Diodia virginiana plant

Family - Rubiaceae

Stems - Trailing to ascending, herbaceous, 4-angled, often with reddish tinge, retrorse pubescent to glabrous, to +15cm tall, +30cm long.

Leaves - Opposite, sessile. Pairs of opposing leaves joined at base by sheathing stipules. Stipules with 3-5 bristle-like lobes on upper margin. Middle lobe longest, to 5mm long. Leaf blades to 4cm long, 1.5cm broad, elliptic below, becoming linear-oblong above, entire, with antrorse strigillose margins, glabrous or sparse pilose at base on margins, typically acute.

Diodia virginiana leaves

Inflorescence - Single or double flowers from leaf axils. Flowers sessile.

Flowers - Corolla white, 4-lobed, salverform. Corolla tube to 8mm long, glabrous. Lobes 5-6mm long, 2.5mm broad spreading, white, glabrous externally, dense pubescent internally. Stamens 4, alternating with corolla lobes, adnate at apex of corolla tube, exserted. Filaments to +4mm long, white, glabrous. Anthers 2mm long, white. Style 1.1cm long, glabrous, filiform, flattened. Stigmas 2, 4mm long. Ovary 2-locular. Calyx tube to 4mm long (in flower), 2-lobed. Lobes 6mm long, attenuate, ciliate-margined. Caylx accrescent. Fruit to 8mm long, pubescent to glabrous.

Diodia virginiana corolla

Diodia virginiana corollaCorolla tube.

Flowering - June - September.

Habitat - Wet soils, pond margins, wet meadows.

Origin - Native to U.S.

Other info. - This species can be found in the lower 1/3 of Missouri. Our plants belong to variety virginiana. Another variety, var. attenuata Fern., has more narrow fruits and is not found in Missouri.
Steyermark splits var. virginiana into two forms. Form hirsuta (Pursh) Fern. has pubescent stems and fruits. Form virginiana has glabrous stems and fruits and is more common in our state.

Photographs taken in the Croatan National Forest, NC., 7-11-02.


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