Matelea biflora
Matelea radiata
star milkvine, two flower matelea, two-flower milkvine
falfurrias milkvine
4–10, decumbent, often branched near base, 7–40 cm, hirsute with long eglandular and minute glandular trichomes.
1–10, twining, 30–200 cm, retrorse-puberulent with curved, eglandular 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 colleter on each side of petiole;
petiole 0.3–0.6 cm, puberulent with curved, eglandular trichomes and inconspicuously glandular-hirtellous;
blade deltate to narrowly lanceolate, 1–2 × 0.2–0.7 cm, base truncate to shallowly cordate, with 2–4 laminar colleters, apex acute, surfaces sparsely puberulent with curved, eglandular trichomes and very inconspicuously glandular-hirtellous on veins abaxially, glabrate adaxially.
solitary, umbelliform, extra-axillary, sessile or subsessile, 1–2-flowered.
solitary, extra-axillary, sessile or subsessile, 1(or 2)-flowered.
3–11 mm, hirsute with long eglandular and minute glandular trichomes.
1–3 mm, puberulent with curved, eglandular trichomes and inconspicuously glandular-hirtellous.
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, narrowly lanceolate, 2–3 mm, apex acute, sparsely puberulent with curved, eglandular trichomes and inconspicuously glandular-hirtellous;
corolla yellowish green abaxially, brown with green tinge adaxially, not or very faintly reticulate, campanulate, tube 1–2 mm, lobes ascending, lanceolate, 5–6 mm, glabrous;
corona of 5 laminar segments opposite anthers, apex retuse, white with purple adaxial patch, 2.5–3 mm, greatly exceeding style apex, glabrous;
apical anther appendages white, deltoid;
style apex green, pentagonal-lobed, flat with central, bifid protrusion.
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, ovate, 6–7 × 4–5 mm, margins winged, chalazal end scarcely erose, faces inconspicuously rugulose;
coma 2–3 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.
gray-striate, lance-ovoid to fusiform, 5–8 × 0.8–1 cm, apex acuminate, smooth to moderately tuberculate, mostly on lower two-thirds, sparsely puberulent to glabrate.
, suffrutescent, not corky.
Matelea biflora
Matelea radiata
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 radiata is very uncommon and possibly endemic to Brooks, Hidalgo, and Starr counties in southern Texas. Only three flowering specimens are known, from near Falcon Lake and La Joya, in the Lower Rio Grande Valley, and the type collection from the imprecise location of Falfurrias. Based on the restriction of all other collections to the vicinity of the Rio Grande Valley, including fruiting specimens assigned here tentatively, it is possible that the type collection was made a good deal south of Falfurrias. Similar in most respects to close relatives M. parvifolia and M. sagittifolia, M. radiata is readily differentiated by elongate white corona segments that greatly exceed the style apex. Based on scant evidence, it is possible that the follicles are more densely tuberculate than in the related species. It is wholly disjunct from the range of M. parvifolia, which is found only as far east as the Big Bend region, and it is known to co-occur with M. sagittifolia only in the vicinity of Falcon Lake. Considering the rarity of M. radiata and development pressures in the Lower Rio Grande Valley, this species should be considered to be of extreme conservation concern.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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