Mexico. “Circa Mexico”, J. Berlandier 751 (holotype: G [G00418346]).

Perennial herb, 0.7–1 m tall, perhaps occasionally annual or only persisting for a few years. Stems angled to winged, lacking spinescent processes, usually erect, but occasionally lax and somewhat scrambling; young stems densely to sparsely pubescent with glandular, simple uniseriate trichomes 0.5–2 mm long, the trichomes (2–)4–15 celled, the basal cells larger, the trichomes drying translucent; new growth densely glandular pubescent and sticky; bark of older stems greenish brown. Sympodial units difoliate, the leaves not geminate. Leaves simple, occasionally shallowly toothed, 2.5–6.5 cm long, 1.2–2.8 cm wide, elliptic to ovate, widest in the lower half, membranous; adaxial and abaxial surfaces evenly and densely glandular-pubescent with simple uniseriate trichomes to 2 mm long, these denser abaxially and along the veins; principal veins 4–6 pairs, drying paler than the lamina; base attenuate onto the petiole; margins entire to shallowly and irregularly toothed, the teeth mostly in the basal third of the blade, usually with minute glandular papillae with 2-celled glandular tips that dry dark brown; apex acute to acuminate; petiole 0.5–2 cm, narrowly winged from the attenuate leaf base. Inflorescences 0.8–2.5 cm long, unbranched, internodal, with 3–6 flowers (usually ca. 4) clustered in the distal third or quarter (sub-umbelliform), densely glandular-pubescent like the stems and leaves; peduncle 0.8–2.5 cm long; pedicels 0.7–0.9 cm long at anthesis, ca. 0.5 mm in diameter at the base, ca. 1 mm in diameter at the apex, slender and tapering, densely glandular-pubescent with short uniseriate trichomes and glandular papillae, with only a few trichomes to 2 mm long present, spreading at anthesis, articulated at the base; pedicels scars closely packed in the distal part of the inflorescence, with the lowermost ca. 1 mm distant from the rest. Buds globose to broadly ellipsoid, the corolla strongly exserted from the calyx tube before anthesis. Flowers 5-merous, all perfect. Calyx tube 1.5–2 mm long, conical to cylindrical, the lobes 0.5–1 mm long, 0.8–1 mm wide, deltate to triangular, the tips obtuse or rounded, densely glandular-pubescent like the pedicels with uniseriate trichomes and papillae. Corolla 10–15 mm in diameter, white or pale purple with a darker brownish purple central star, stellate, lobed 1/2 to 2/3 of the way to the base, the lobes 3.5–5 mm long, 2–3 mm wide, triangular, reflexed to spreading at anthesis, the abaxial surfaces densely papillate, the trichomes not glandular. Stamens equal; filament tube to 0.5 mm; free portion of the filaments 0.5–1 mm long, glabrous or with a few weak tangled simple uniseriate trichomes adaxially; anthers 2.5–3.5 mm long, 0.5–1 mm wide, ellipsoid, bright yellow, poricidal at the tips, the pores elongating to slits with age. Ovary conical, glabrous; style 4.5–6 mm long, sparsely pubescent with weak tangled trichomes to densely papillate in the lower part where included in the anther cone, only slightly (ca. 0.5 mm) exserted from the anther cone; stigma capitate, densely papillate. Fruit a globose berry, 0.5–1 cm in diameter, green to deep purple (red when ripe? Martínez 1211); opaque (mature fruits not seen on live plants but not markedly translucent when dry), the pericarp thin, matte; fruiting pedicels 6–9 mm long, enlarging from a base 0.6–1 mm in diameter to an apex 1–1.5 mm in diameter, not distinctly woody, spreading; fruiting calyx not accrescent, the tube less than 1 mm long, the lobes 1.5–2 mm long, appressed to the berry, venation very apparent and thickened. Seeds 10–30 per berry, 1–1.5 mm long, 1–1.2 mm wide, tear-drop shaped, reddish gold, the surfaces minutely putted, the testal cells pentagonal. Stone cells 2–4 (–6) per berry, 0.5–0.7 mm in diameter, pale cream. Chromosome number: not known.

(Figure 38) Solanumpruinosum occurs from the state of Nuevo León in Mexico south to the state of Oaxaca, across the central Volcanic Belt (Rzedowski 1978).

Solanumpruinosum occurs in pine-oak forests, mesophyll forests and open areas from 1,000 to 2,500 m elevation.

Mexico [Puebla]. Tomakilit (Nahuat, Amith JDA-2084), Tomakilit (silvestre) (Nahuat, Jiménez Chimil JDA-30248).

None recorded.

Least Concern (LC). Solanumpruinosum is widespread in Mexico but is not as common as S.nigrescens. For EOO see Table 6.

Solanumpruinosum differs from S.nigrescens and S.douglasii, with which it is sympatric, in its glandular pubescence. It is possible that these specimens represent isolated glandular populations of those two taxa, but in the absence of data showing this we elect to recognise these populations at the species level until further work across the range in Mexico is done. The three taxa share numerous stone cells (ca. 5–6, more in S.nigrescens) in the ripe berries, and subumbellate to somewhat “racemose” inflorescences. The flowers of S.pruinosum are intermediate in size between S.douglasii (15–20 mm in diameter) and S.nigrescens (8–10 mm).

Label data from Martínez 1211 (MO) note the berries as “rojo” (red), but no other specimens have this data, so we suspect it is either a mistake, or an interpretation of purplish red.

The locality on the type specimen of S.pruinosum is only given as “circa Mexico”, but is likely to have been collected in central Mexico; Berlandier was in Mexico City and vicinity from the time of his arrival in Mexico in 1826 until his journey north to the Tamaulipas-Texas borderlands in late 1827 (Lawson 2012).

We have not been able to trace any duplicates of the type specimens of S.dasyadenium and var. uberius, both described from material held in Berlin (Bitter 1912a) and subsequently destroyed. Until we better understand the range of variation in these taxa, and their relationship to S.douglasii and S.nigrescens, we prefer not to neotypify these names at present.

See Suppl. materials 1 and 3.