Trachelospermum difforme (Walter) A. Gray

Climbing Dogbane

© SRTurner

Family - Apocynaceae

Habit - Lianas, sometimes appearing herbaceous, sometimes more or less emergent aquatics. Sap milky.

	Twining habit.
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Stems - Lax, 2-5 m or more, woody or mostly herbaceous, twining and climbing in other vegetation, often rooting at the nodes, glabrous or with sparse, short, reddish hairs, especially when young.

	Young stem.
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	Older stem (and inflorescence with young fruits).
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Leaves - Opposite, simple, petiolate. Petioles 4-5 mm long. Leaf blades 2.5-9.0 cm long, 0.5-5.5 cm wide, variable in shape from broadly ovate or nearly circular to lanceolate or narrowly oblong-elliptic, narrowed or more commonly tapered to a sharply pointed tip, angled, tapered, or rarely rounded at the base, the upper surface glabrous and sometimes somewhat shiny, the undersurface sparsely to densely short-hairy.

	Leaf adaxial. Shape is highly variable.
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	Leaf abaxial.
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	Leaf abaxial surface.
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	Milky sap.
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Inflorescences - Loose axillary clusters or small panicles.

	Inflorescence.
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	Inflorescence.
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Flowers - Calyces glabrous or sparsely hairy, the lobes 2.5-3.0 mm long, narrowly ovate-triangular. Corollas funnelform to trumpet-shaped, lacking appendages, the tube 5-7 mm long, the lobes 1.5-2.0 mm long, yellow with red coloration on the inner surface toward the top of the tube and the lobes, sparsely hairy inside the tube. Stamens attached near the midpoint of the corolla tube, the anthers incurved and adhering to the stigma, appearing arrowhead-shaped with a pair of slender basal lobes. Nectar glands 5, positioned around the ovary bases alternating with the stamens. Style elongate, the stigma appearing somewhat umbrella-shaped with a broadly club-shaped body that is expanded into a basal wing.

	Flowers.
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	Sepals.
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	Corollas.
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Fruits - Follicles 10-23 cm long, usually pendulous, slender, maturing reddish, dehiscing along the longitudinal suture. Seeds 0.8-11 mm long, truncate to tapered at the base, the tip with a dense tuft of yellowish gray hairs 14-15 mm long.

	Fruits.
© SRTurner

Flowering - June - July.

Habitat - Bottomland forests, swamps, streambanks, oxbows, ditches, roadsides.

Origin - Native to the U.S.

Lookalikes - None when flowering.

Other info. - This climbing plant is found in the southeastern portion of the continental U.S. It is uncommon in Missouri, which lies at the northwestern edge of its range. However, it areas where it is found it can be quite common. Sterile specimens tend to blend in with other vegetation, but when flowering or fruiting it is distinctive. Key characters to look for are the pale yellow, trumpet-shaped flowers, often found with some reddish wilted corollas on the same inflorescence, the very long, slender fruits, and vining plants with well-spaced opposite leaves. A confirming character is the milky sap.

Synonyms for this species are Thyrsanthella difformis (Walter) Pichon and Echites difformis Walter.

Photographs taken at Otter Slough Conservation Area, Stoddard County, MO, 9-8-2019 and 6-10-2023, Big Cane Conservation Area, Butler County, MO, 6-9-2023, and Hemenway Conservation Area, Ripley County, MO, 6-9-2023 (SRTurner).