Solanum dasyphyllum [Schumach. & Thonn. ]

Solanum dasyphyllum

Citation author:

Schumach. & Thonn.

Citation:

Beskr. Guin. Pl. 126 [146]. 1827.

Type:

GUINEA. Negerne, P. Thonning 144 (lectotype, designated by Vorontsova & Knapp 2012: C! [IDC microfiche 2203 102:I.1-2, “362”]; isolectotypes, C! [IDC microfiche 2203 102:I.3-4], G-DC! [G00130373]).

Last edited by:

Sandra Knapp (May 2014)

Written by:

Maria S. Vorontsova & Sandra Knapp

Habit:

Erect herb to shrub, 0.5-1 m, densely prickly. Young stems terete, sparsely to densely stellate-pubescent and densely prickly, with porrect, variously stalked trichomes, the stalks 0.5-2.5 mm long, often lignified, the rays ca. 4, 0.5-1 mm long, the midpoints ca. same length as the rays or up to 1 mm long, the prickles 2-7 mm long, 0.5-1.5 mm wide at base, straight, flattened, perpendicular to the stem, yellowish, glabrous, spaced 5-50 mm apart; bark of older stems glabrescent, gray-brown.

Sympodial structure:

Sympodial units difoliate, not geminate.

Leaves:

Leaves simple, the blades 10-35 cm long, 6-20 cm wide, 1.2-2 times longer than wide, elliptic, chartaceous, drying discolorous to almost concolorous, yellow-green to red-brown; adaxial surface sparsely to densely pubescent, the trichomes with a bulbous base, no visible rays or stalk, the midpoint 0.5-2 mm long; abaxial surface sparsely to densely stellate-pubescent, with porrect, stalked trichomes, the stalks 0.1-0.5 mm long, sometimes longer, broad and lignified, the rays 4(-5), 0.4-0.7 mm long, the midpoints ca. same length as the rays or to 0.8 mm long, with 10-15 prickles on both surfaces; the primary veins 5-8 pairs, the tertiary venation visible abaxially; base attenuate, sometimes cuneate; margins lobed, the lobes (3-)4-5(-6) on each side, 3-9 cm long, extending 1/2-2/3 of the distance to the midvein, broad-deltate, usually with extensive secondary lobing, apically acute to obtuse; apex acute to obtuse; petiole 0-4 cm long, less than 1/6 of the leaf blade length, usually decurrent, sparsely to densely pubescent, with 0-5 prickles.

Inflorescences:

Inflorescences apparently lateral, 4-7 cm long, unbranched, with 5-10 flowers, 1-4 flowers open at any one time, sparsely to densely stellate-pubescent, with 0-30 prickles; peduncle 0-3 mm long; pedicels 2-3 cm long in long-styled flowers, 0.7-2.5 cm long in short-styled flowers, erect, articulated at the base, sparsely to densely stellate-pubescent, with 5-30 prickles on long-styled flowers, 0-30 prickles on short-styled flowers; pedicel scars spaced ca. 5 mm apart.

Flowers:

Flowers 5-merous, heterostylous and the plants andromonoecious, with the lowermost flower long-styled and hermaphrodite, the distal flowers short-styled and staminate. Calyx 10-30 mm long in long-styled flowers, 8-20 mm long in short-styled flower, stellate-pubescent, with 20-100 prickles in long-styled flowers, unarmed or with fewer prickles in short-styled flowers s, the lobes 12-25 mm long in long-styled flowers, 7-10 mm long in short-styled flowers, deltate, apically acute to long-acuminate. Corolla 3.5-6 cm in diameter in long-styled flowers, 1.5-3.5 cm in diameter in short-styled flowers, pale mauve to purple, sometimes white, almost rotate, often tearing, lobed for 1/4-1/3 of the way to the base, the lobes 5-20 mm long, 10-25 mm wide in long-styled flowers, 2-7 mm long and 7-15 mm wide in short-styled flowers, broad-deltate, spreading, not opening fully in long-styled flowers, moderately stellate-pubescent abaxially, the trichomes porrect, sessile, the rays 4-6, 0.1-1 mm long, the midpoints to 1 mm long. Stamens equal, with the filament tube ca. 2 mm long, the free portion of the filaments 0.5-1.5 mm long; anthers 6.5-7.5 mm long in long-styled flowers, 5.5-7.5 mm long in short-styled flowers, connivent, tapering, poricidal at the tips. Ovary with simple glandular hairs on the upper 1/3; style 0.8-1.3 cm long, stout, straight to curved, glabrous with simple glandular trichomes near the base.

Fruits:

Fruit a spherical to somewhat elongate berry, 1(-2) per infructescence, 2.5-4 cm in diameter, the pericarp smooth, dark green with pale green and cream markings when young, yellow at maturity, glabrous; fruiting pedicels 1.5-3 cm long, 1.8-3 mm in diameter at base, woody, erect to pendulous, with 20-100 prickles; fruiting calyx lobes elongating to 15-40 mm long, ca. 1/3 the length of the mature fruit, reflexed, with 20-100 prickles.

Seeds:

Seeds ca. 50-100 per berry, 2.8-4.5 mm long, 2-3.5 mm wide, flattened-reniform, orange to brown or almost black.

Chromosome number:

2n=24 (Omidiji 1979)

Distribution:

Common throughout the highlands of western, central and eastern Africa, between ca. 15°N and ca. 10°S, sometimes found as far south as South Africa; usually a forest species but also found on hillsides, savannah, grassland, or wasteland, frequently near water; 600-1600 m elevation, although sometimes found at sea level.

Phenology:

Flowering and fruiting throughout the year.

Phylogeny:

Solanum dasyphyllum is sister to S. macrocarpon in the Old World clade within subgenus Leptostemonum.(Levin et al., 2006). Solanum macrocarpon and S. dasyphyllum are part of the large Anguivi grade (Vorontsova et al. 2013) containing S. anguivi and other small-leaved species from East Africa.

Commentary:

Solanum dasyphyllum is a common plant of the African highlands. Useful characters for recognition include large leaves with pointed lobes and secondary lobing, attenuate leaf bases, straight prickles, and prominent elongate midpoints on the trichomes of the adaxial leaf surfaces. Some representatives have leaves that are less lobed, with rounded lobes, sometimes without prickles, and with variable quantity of indumentum. The sizeable porrect trichomes have a maximum of 4 or 5 rays, a useful identification feature seemingly overlooked by other treatments. Extensive sampling across populations in Uganda demonstrates that unlike the majority of African prickly Solanum species, the number of trichome rays in S. dasyphyllum does not exceed 5 (Bukenya & Carasco 1994). For SEM photographs and detailed information on trichomes, pollen and seed surface see Bukenya & Carasco (1999).

It is widely accepted that S. dasyphyllum is the wild progenitor of the cultivated S. macrocarpon (Jaeger 1985; Gonçalves 2005). Less hairy forms of S. dasyphyllum with fewer prickles and larger fruit were presumably selected to produce the visibly different S. macrocarpon. Opinions vary on whether to distinguish S. macrocarpon and S. dasyphyllum. Bitter (1923), Heine (1963), and Friis (2006a, 2006b) recognize them as separate while Bukenya (1980), Bukenya & Carasco (1994, 1999), Jaeger (1985), and Gonçalves (2005) regard them as conspecific. The distinction between the cultivated S. macrocarpon and the wild S. dasyphyllum is largely artificial and maintained here for practical purposes; we feel that cultivated plants are experiencing an entirely different selection regime than their still wild progenitors, and that recognition at the specific level emphasizes this difference in evolutionary trajectory. Solanum dasyphyllum can be distinguished from S. macrocarpon by the presence of prominent prickles and indumentum, as well as fruit less than 4 cm in diameter (versus fruit more than 4 cm diameter in S. macrocarpon). Solanum dasyphyllum generally has larger and more dissected leaves, and its leaf lobes are more pointed than those of S. macrocarpon.

Several species of native African and introduced Solanum have confusingly similar large leaves, pointed leaf lobes, straight yellow flattened prickles on both leaf surfaces, and elongated midpoints on trichomes of the adaxial leaf surface: S. aculeatissimum, S. cerasiferum, S. nigriviolaceum, and S. umtuma can all be superficially similar to S. dasyphyllum if not in flower. Solanum dasyphyllum can be distinguished by its lack of distinct petiole or long-attenuate leaf bases, almost rotate corolla on short-styled flowers, and only 4(5) rays on the stellae on vegetative parts of the plant.

Dammer described S. farini based on plants introduced by the nurserymen Damman & Co. in Italy, and commented mainly on its massive size. The description is extremely marginal and there is some doubt as to whether this name is validly published, but the plate accompanying the description clearly shows the secondary leaf lobing characteristic of S. dasyphyllum (Dammer 1896). We have chosen this plate as the lectotype of S. farini in the absence of any other original material. We have selected the only extant material seen of Tessmann 404 (K000441457) as the lectotype of Bitter’s S. dasyphyllum var. inerme; no herbarium was cited in the protologue and the collection was cited as “Tessmann 404 p.p.”

References:

Bitter, G. 1923. Solana Africana. IV. Spec. Nov. Regni Veg. Beihefte 16: 1-320.

Bukenya, Z.R. 1980. Studies in the taxonomy of Solanum L. in Southern Ghana. M.Sc. Thesis, University of Ghana, Legon.

Bukenya, Z.R., & J.F. Carasco 1994. Hair types, pollen, and seed surfaces of Solanum macrocarpon complex and Solanum linnaeanum (Solanaceae). Israel J. Pl. Sci. 42: 41-50.

Bukenya, Z.R., & J.F. Carasco 1999. Ethnobotanical aspects of Solanum L. (Solanaceae) in Uganda.
In: Nee, M., Symon, D. E., Lester, R. N., & Jessop, J. P. ed(s). Solanaceae IV. Advances in botany and utilization, pp. 345-360. Royal Botanic Gardens, Kew.

Dammer, U. 1896. Miscellen. Wiener Ill. Gart.-Zeitung 1896: 404-418.

Friis, I. 2006. Solanum. In: M. Thulin (ed.), Flora of Somalia 3: 206-219. Royal Botanic Gardens, Kew, United Kingdom.

Friis, I. 2006. Solanaceae. In: I. Hedberg et al. (eds.), Flora of Ethiopia and Eritrea 5: 103 – 160. Addis Ababa University. Addis Ababa, Ethiopia and Uppsala University, Uppsala, Sweden.

Heine, H.H. 1963. Solanaceae. In: Hepper, F. N. (ed.), Flora of West Tropical Africa, ed. 2, pp. 325-335. Crown Agents, London.

Jaeger, P.-M.L. 1985. Systematic studies in the genus Solanum in Africa. PhD thesis, University of Birmingham, United Kingdom.

Gonçalves, A.E. 2005. Solanaceae. In: G. V. Pope, R. M. Polhill & E. S. Martins (eds.), Flora Zambesiaca 8(4): 1-124.

Levin, R.A., N.R. Myers, & L. Bohs 2006. Phylogenetic relationships among the "spiny" solanums (Solanum subgenus Leptostemonum). Amer. J. Bot. 93: 157-169.

Vorontsova, M. S., S. Stern, L. Bohs, and S. Knapp. 2013. African spiny Solanum (subgenus Leptostemonum, Solanaceae): a thorny phylogenetic tangle. Bot. J. Linn. Soc. 173: 176-193. doi:10.1111/boj.12053

Common names and uses:

Local Names. Ethiopia: Turkenturk. Nigeria: Afifa mwo, igb’a egugu, Gbere Aja. Rwanda: Igitoborwa. Uganda: Entobotoba (plant), Entobo (fruits) (Bukenya & Carasco 1999).

Uses. Fruit used medicinally and sometimes eaten. For further information on uses and names in Uganda see Bukenya & Carasco (1999).

Solanaceae Source

A global taxonomic resource for the nightshade family

Solanaceae

Solanum dasyphyllum Schumach. & Thonn.

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