Matelea biflora
Matelea chihuahuensis
star milkvine, two flower matelea, two-flower milkvine
Chihuahuan hairy milkvine
4–10, decumbent, often branched near base, 7–40 cm, hirsute with long eglandular and minute glandular trichomes.
4–20+, prostrate, 10–50 cm, hispid to hirsute with long eglandular and minute glandular trichomes.
1 or 2 colleters on each side of petiole;
petiole 0.5–2.5 cm, hirsute with long eglandular and minute glandular trichomes;
blade ovate to deltate, 0.8–5 × 0.6–3.2 cm, base shallowly to deeply cordate, with 0–2 laminar colleters, apex acute (rounded), surfaces hirsute with long eglandular and minute glandular trichomes, especially so on veins abaxially.
with 1 or 2 colleters on each side of petiole;
petiole 0.2–1.6 cm, hirsute with long eglandular and minute glandular trichomes;
blade deltate (ovate), 0.7–3.3 × 0.7–2.6 cm, base shallowly to deeply cordate, with 2–4 laminar colleters, apex acute, surfaces densely hirsute with long eglandular and minute glandular trichomes.
solitary, umbelliform, extra-axillary, sessile or subsessile, 1–2-flowered.
solitary, umbelliform, extra-axillary, pedunculate, 2–5-flowered;
peduncle 0.1–0.3 cm, hirsute with long eglandular and minute glandular trichomes.
3–11 mm, hirsute with long eglandular and minute glandular trichomes.
3.5–5 mm, hirsute with long eglandular and minute glandular trichomes.
calyx lobes spreading, oval to ovate, 1.8–2.5 mm, apex rounded or acute, hirsute with long eglandular and minute glandular trichomes;
corolla maroon to dark brown, not reticulate, rotate-campanulate, tube 1–1.5 mm, lobes spreading, ovate to narrowly deltate to spatulate, 3–6 mm, margins usually reflexed, pilose to hirsute adaxially;
corona united to corolla and column near base, composed of 5 united segments forming a ring at base, each with an adaxial incurved appendage arching above or incumbent on anthers, equaling or exceeding style apex, maroon to dark brown, 1–1.5 mm, glabrous;
apical anther appendages white, maroon to brown at base, broadly deltoid;
style apex rounded, flat.
calyx lobes spreading, elliptic, 1.9–3.5 mm, apex acute, hirsute with long eglandular and minute glandular trichomes;
corolla cream with green to pink striations that become reticulate at lobe margins, rotate-campanulate, tube 0.5–1.5 mm, lobes spreading to ascending, plane, oblong to spatulate, 2.4–5 mm, hirsute adaxially at base of lobes;
corona united to column near base, composed of 5 united segments forming a short ring, segments arching over style apex, translucent white to pink, ligulate, 1.5–2 mm, densely, minutely hirtellous;
apical anther appendages pink, deltoid;
style apex pale to dark pink, rounded, convex.
tan to light brown, oval to nearly orbicular or ovate, 8–11 × 7–10 mm, margins broadly winged, chalazal end erose, faces minutely rugose;
coma 2.5–4 cm.
tan to brown, oval to ovate (orbicular), 7–9 × 5–7 mm, margins broadly winged, chalazal end erose, faces rugose;
coma 1.5–3 cm.
not striate, ellipsoid to ovoid, 4.5–8.5 × 1.8–3.5 cm, apex acute, densely muricate (more than 1 protrusion per cm of length), villous to hirsute with long eglandular and minute glandular trichomes.
faintly striate, lance-ovoid (ellipsoid), 4.9–5.7 × 1.7–2.5 cm, apex acuminate, densely muricate, densely villous to hirsute with long eglandular and minute glandular trichomes.
Matelea biflora
Matelea chihuahuensis
Matelea biflora is occasionally found in grasslands and savannas of the southern Great Plains. It is most common on and around the Edwards Plateau of central Texas, where it occurs in grass-dominated habitats including disturbed areas. The range extends mostly northward and westward of that region to central Oklahoma and extreme eastern New Mexico (Lea County), where the species is much less common. Its conservation status in New Mexico merits evaluation. The plants are covered in short, glandular hairs and are malodorous when touched. The flowers occur most often in pairs, hence the common name two-flowered milkvine.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Matelea chihuahuensis was reported in the United States apparently for the first time in 2013 by surveyors in the western piedmont of the Animas Mountains, in the bootheel of New Mexico (Quinn s.n., OKLA; A. McDonnell et al. 2015). However, an earlier collection was made in 1977 in the nearby San Simon Valley (Moir s.n., COLO). Because of its recent discovery in the United States, M. chihuahuensis has not been formally assessed for conservation status; with few known populations limited to Hidalgo County, New Mexico, this species should be considered to be of conservation concern. It is distributed across the state of Chihuahua, Mexico, but is apparently rare throughout its range. In New Mexico and in the bulk of its range in the foothills of the Sierra Madre Occidental in Chihuahua, it occurs in desert grassland in valleys and on mountain slopes. The white and green corollas, hirtellous corona segments, and small follicles are unusual in comparison to related species.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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