Western rocktrumpet

Echites brachysiphon Torrey in W. H. Emory, Rep. U.S. Mex. Bound. 2(1): 158. 1859; Macrosiphonia brachysiphon (Torrey) A. Gray; Telosiphonia brachysiphon (Torrey) Henrickson

Subshrubs, 2–4 dm; rhizomes present. Stems sparsely to densely eglandular-pubescent, especially on younger growth. Leaves opposite or sub­opposite, occasionally subverticillate; petiole 1–2 mm, pubescent; blade ovate-lanceolate to oblong-ovate, (8–)14–35 × (3.5–)6–15(–25) mm, subcoriaceous, base cuneate, rounded, or slightly cordate, margins not revolute, apex acute, acuminate, or rounded, apiculate, surfaces densely eglandular-pubescent abaxially, eglandular-pubescent adaxially. Cymes 1(or 2)-flowered. Peduncles 0–1(–3) mm, pubescent. Pedicels 7–15 mm, pubescent. Flowers: sepals reddish, oblong-ovate, 4–9 × 1–2.2 mm, pubescent; corolla white, often tinged with pink or red, often greenish below, eglandular-pubescent abaxially and adaxially, tube 13–20(–25) × 1.5 mm, throat (11–)15–20(–25) × 4–5 mm, lobes spreading, obliquely ovate, (10–)15–25 × 10–20 mm. Follicles 55–120 × 4–5 mm, pubescent. Seeds 5–7 × 1–1.5 mm.

Flowering summer; fruiting summer–fall. Desert scrub, desert grasslands, pine-oak woodlands; 1000–1600 m; Ariz., N.Mex., Tex.; Mexico (Chihuahua, Sonora).

Mandevilla brachysiphon has the westernmost distribution of our species. Within the flora area, M. brachysiphon is known only from southeastern Arizona (Cochise, Graham, Pima, and Santa Cruz counties), southwestern New Mexico (Hidalgo and Luna counties), and the Franklin Mountains of El Paso County, Texas.