Solanum glaucescens [Zucc. ]

Solanum glaucescens

Citation author:

Zucc.

Citation:

Abh. Math.-Phys. Cl. Königl. Bayer. Akad. Wiss. 2: 325. 1837.

Type:

Grown in the Munich Botanical Garden by Zuccarini from seeds received in 1835 from Karwinsky, collected in Mexico (holotype: M [M0124264, Morton neg. 8691]; isotype: BR [BR0000008366221]).

Last edited by:

Sandra Knapp (May 2014)

Written by:

John L. Clark and Sandra Knapp

Habit:

Vine, stems robust, herbaceous to woody, 0.25 to 0.6 cm in diameter, the internodes 1–5 cm long, glabrous, with paired spines at base of each petiole, these stout, 2–8 mm long, recurved.

Sympodial structure:

Sympodial units plurifoliate.

Leaves:

Leaves deciduous in the dry season, simple, the blades 3.5–9 × 1.5–5.5 cm, 1.6–2.3 times as long as wide, narrowly oblong to ovate, chartaceous, glabrous adaxially and abaxially, often armed abaxially on midrib with recurved prickles; major lateral veins 3–6 on each side; base cuneate to decurrent; margin entire; apex acuminate; petioles 1–4 cm, glabrous, often armed with recurved prickles.

Inflorescences:

Inflorescences 7–10 × 15–20 cm, terminal or lateral, branched, with 5–12 flowers, the axes glabrous, rarely armed with recurved prickles; peduncle 1–2 cm; rachis 2–7 cm; pedicels 5–10 mm and slender at anthesis, articulated at the base; fruiting pedicels elongating to 3–4 cm and becoming woody.

Flowers:

Flower buds ellipsoid, the corolla exserted from the calyx tube long before anthesis. Calyx campanulate, spreading, the tube 2–4 mm, nearly entire with five shallowly subcaudate, broadly deltate, acuminate lobes, glabrous except for the puberulent tips. Corolla 2–4 cm in diameter, spreading at anthesis, stellate, with interpetalar tissue nearly absent, pale yellow to yellow-green, lobed nearly to the base, the lobes ca. 1.5 × 0.5 cm, lanceolate to broadly deltate, acute at apices, glabrous abaxially, glabrous adaxially except puberulent at tips. Stamens 10–15 mm long; filaments unequal, with four 1.5–2 mm long, the fifth 3.5–4.5 mm long, glabrous; anthers nearly equal, 6–9 × 1.5–2 mm, the one on the longer filament slightly larger, oblong, connivent, white to yellowish-orange, poricidal at the tips, the pores lengthening to slits with age. Ovary glabrous; style in short-styled flowers ca. 2 mm long x 0.5 mm wide, not seen in long-styled flowers, straight, glabrous; stigma truncate.

Fruits:

Fruit a globose berry, ca. 3.5 cm in diameter, mottled dark green and light green when immature, turning orange when mature with orange-red pulp, the pericarp glabrous, rugose when dry.

Seeds:

Seeds 4-5 × 3-5 mm, flattened-reniform to somewhat ovoid, light brown, the surfaces minutely pitted, the testal cells pentagonal in shape, the lateral cell walls elongate and the seed appearing hairy when outer testal walls break down.

Chromosome number:

Not known

Distribution:

Native to deciduous forests of southern Mexico (States of Chiapas, Guerrero, Oaxaca, and Puebla); 10-1400 m.

Phylogeny:

Solanum glaucescens is a member of the Allophyllum/Wendlandii clade (Bohs 2005; Stern et al. 2011) that is part of a large polytomy in Clade II (sensu Särkinen et al. 2013). Despite having prickles, this group appears not to be closely related to the spiny solanums (Leptostemonum). Section Aculeigerum comprises only the prickle-bearing members of this clade.

Commentary:

Solanum glaucescens differs from other members of section Aculeigerum by the presence of paired recurved prickles flanking the petioles (Figure 4). These appear stipular, but stipules are absent in the Solanaceae, and these are prickles like those found on the rest of the plant. The similar situation occurs in the unrelated S. microphyllum (Lam.) Dunal of the West Indies (Knapp, 2009). Solanum glaucescens differs from S. bicorne with which it is partly sympatric in its widely spaced leaves (not clustered as in S. bicorne), smaller yellowish green rather than white flowers and in its glabrous leaf undersides. Solanum glaucescens is usually a more delicate plant than S. bicorne. Trichomes, if present, on all parts of S. glaucescens are small and unicellular, not the uniseriate trichomes with elongate basal cells of S. bicorne.

The illustration of Solanum sagraeanum in the plates (De la Sagra, 1855: pl. 62) accompanying the botany volumes of de la Sagra’s Historia fisica, politica y natural de la isla de Cuba published five years after the protologue (Richard, 1850) is clearly S. glaucescens. The paired recurved prickles at the base of the petioles are clearly shown, but the heterandrous flowers clearly described in the protologue (“Uno de sus estambres es constantamente mayor que los otros cuatro.” [One of the stamens is always longer than the other four]; Richard, 1850: 124) are not; specimens at P and K collected by de la Sagra (see below) have heterandrous flowers and paired prickles. No other collections of S. glaucescens from Cuba have been seen, and its occurrence on Cuba has not been reconfirmed. The type of Solanum sagraeanum may represent a cultivated collection and/or a mis-labeling of the collecting locality. Several duplicates of a collection attributed to Ramón de la Sagra exist in the Paris herbarium. We have selected that labeled as “Herbarium Richard” and “Solanum punctulatum nob. Sagræanum nob.” (P00370903) as the lectotype as it was clearly part of A. Richard’s herbarium and is indicated as a new species on the sheet. Other sheets attributed to de la Sagra (see synonymy) appear to be duplicates and are here recognized as isolectotypes.

References:

Bohs, L. 2005. Major clades in Solanum based on ndhF sequences. Pp. 27-49 in R. C. Keating, V. C. Hollowell, & T. B. Croat (eds.), A festschrift for William G. D’Arcy: the legacy of a taxonomist. Monographs in Systematic Botany from the Missouri Botanical Garden, Vol. 104. Missouri Botanical Garden Press, St. Louis.

De la Sagra, R. 1855. Historia fisica, politica y natural de la isla de Cuba. Vol. 12. Botanica. Atlas. Arthus Bertrand, Paris.

Richard, A. 1850. Fanerogamia o Plantas Vasculares. In: R. de la Sagra, editor. Historia fisica, politica y natural de la isla de Cuba. Vol. 11. Arthus Bertrand, Paris. http://www.biodiversitylibrary.org/item/36569#page/3/mode/1up

Särkinen, T., R.G. Olmstead, L. Bohs & S. Knapp. 2013. A phylogenetic framework for evolutionary study of the nightshades (Solanaceae): a dated 1000-tip tree. BMC Evolutionary Biology 13: 212. doi: 10.1186/1471-2148-13-214

Stern, S. R., M. de F. Agra, and L. Bohs. 2011. Molecular delimitation of clades within New World species of the “spiny solanums” (Solanum subgenus Leptostemonum). Taxon 60: 1429-1441.

Common names and uses:

Mexico. Puebla: “cuatomate” (Huerta Z. & Huerta Z. 1); Oaxaca: “zarza” (Elorsa 301).

Solanaceae Source

A global taxonomic resource for the nightshade family

Solanaceae

Solanum glaucescens Zucc.

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