3. Mandevilla lanuginosa (M. Martens & Galeotti) Pichon, Bull. Mus. Natl. Hist. Nat., sér. 2. 20: 106. 1948.
Woolly rocktrumpet
Echites lanuginosus M. Martens & Galeotti, Bull. Acad. Roy. Sci. Bruxelles 11(1): 357. 1844 (as lanuginosa); Macrosiphonia lanuginosa (M. Martens & Galeotti) Hemsley; Telosiphonia lanuginosa (M. Martens & Galeotti) Henrickson
Shrubs, 2–5(–10) dm; rhizomes absent. Stems densely eglandular-pubescent, especially on younger growth. Leaves opposite, rarely subopposite; petiole 1–3 mm, pubescent; blade oblong to ovate or elliptic, 15–30(–40) × 7–16(–25) mm, subcoriaceous, base rounded or subcordate, margins revolute, apex acute, rounded, or truncate, apiculate, surfaces densely grayish white eglandular-pubescent abaxially, eglandular-pubescent adaxially. Cymes 1(or 2)-flowered. Peduncles 0.5–1.5 mm, pubescent. Pedicels 3.5–9 mm, pubescent. Flowers: sepals reddish, oblong-lanceolate, 8–12.5 × 1.5–3 mm, pubescent; corolla white, often tinged with pink or red, often becoming ferruginous upon drying, eglandular-pubescent abaxially and adaxially, tube 40–80(–100) × 2.5–3 mm, throat 14–25 × 5–7 mm, lobes spreading, obliquely ovate, 15–35 × 13–23 mm. Follicles 50–100 × 3–4 mm, pubescent. Seeds 7–8 × 1.4–1.6 mm.
Flowering spring–fall; fruiting summer–fall. Grasslands and openings in thorn scrub vegetation; 0–300 m; Tex.; Mexico (Durango, Hidalgo, Nuevo León, San Luis Potosí, Tamaulipas).
Mandevilla lanuginosa occurs at lower elevations than other Mandevilla species in the flora area and is characteristically found in openings in Tamaulipan thorn scrub and mesquite woodlands in southern Texas. Mandevilla lanuginosa is sometimes confused with M. macrosiphon; characters separating the two species are discussed under the latter taxon.