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Magnoliopsida
Solanum umbellatum Mill.
EOL Text
The stems and inflorescence axes of S. umbellatum have a shaggy appearance due to the abundant long-stalked stellate hairs. The leaves are scabrous and strongly discolorous, green above and light yellowish below. The stipitate-glandular trichomes visible at 6x magnification are diagnostic for this species, and easily distinguish it from any other species like it in Central America. The sessile trichomes on the upper leaf surfaces distinguish it from other similar South American taxa (S. conglobatum, S. fulgens), both of which have multiseriate stalks on the trichomes of the upper leaf surfaces.Roe (1967) did not find a type specimen for S. umbellatum in the General Herbarium at BM. The protologue states that the plant was received from William Houstoun, from “Campeachy” (the Yucatán peninsula). Specimens from Houstoun sent to Miller can also be found in the Sloane Herbarium at BM; a search of the relevant volumes revealed one small specimen (HS 146: 37, upper R hand fragment) with a label in Houstoun’s hand. The polynomial on the label (“Solanum arborescens, non spinosum: salicis foliis asperis; flore umbellate, albo”), however, does not match the protologue and there is no indication of locality. This is a potential lectotype, but it may be more reasonable to neotypify this widespread and common species with a modern collection from the original area of collection.
Solanum umbellatum is a typical member of Solanum section Brevantherum (the Brevantherum clade of Bohs, 2005). Its phylogenetic position within the Brevantherum clade has not been investigated using molecular data.
Solanum umbellatum is a common weedy species found throughout Mexico, Central America, the West Indies, and in South America along the lower Andean slopes from Colombia to Peru and Venezuela. Frequently a member of open secondary-growth vegetation, its habitats include moist ravines, dry savannahs, forest openings, field borders, and thickets along roads and streams at elevations up to 2250 m.
- Bohs, L.. 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.
- Roe, K.E.. A revision of Solanum sect. Brevantherum (Solanaceae) in North and Central America. Brittonia 19: 353-373.
- Roe, K.E.. Terminology of hairs in the genus Solanum. Taxon 20: 501-508.
- Roe, K.E.. A revision of Solanum section Brevantherum (Solanaceae). Brittonia 24: 239–278.
Habit
Shrubs or small trees 1-6 m high, openly branched, unarmed. Trunks to 10 cm in diameter; bark of older stems pale brown, the young branches terete, scabrous or granular-pubescent, glabrescent, the hairs mixed sessile, short- and mostly long- and coarse-stalked, porrect-stellate and multangulate.
Sympodial Structure
Sympodial units plurifoliate, axillary leaves present or absent, lanceolate or ovate.
Leaves
Leaves simple, the blades usually 7-28 x 2.5-10 cm, ca. 2.5-6 times as long as wide, lanceolate, elliptic or oblanceolate, somewhat coriaceous, green and scabrous or scabridulous adaxially, the hairs sparse, spaced or touching, rarely overlapping, sessile, porrect-stellate, moderately to densely whitish pubescent abaxially, the hairs mixed sessile, short- and long- and relatively thin-stalked, porrect-stellate and multangulate; unarmed; main lateral veins 7-11 on each side of midvein; base long-attenuate, decurrent along entire length of petiole or nearly so; margin entire; apex attenuate or acuminate; petioles 0-0.6 (-1) cm, ca. 1/100-1/20 the length of the blades, scabrous, the hairs mixed sessile, short- and relatively long- and coarse-stalked, mostly porrect-stellate.
Inflorescences
Inflorescences 5-22 cm, terminal, becoming lateral due to continued growth of stem, ca. 3-6 times branched, with ca. 20-80 flowers, the axes unarmed, hirsute, the hairs mixed sessile, short- and partly long- and usually coarse-stalked, porrect-stellate and multangulate; peduncle 3-21 cm, 1.3-5 mm thick; rachis 0.4-1.5 cm; pedicels 2-6 mm in flower and fruit, closely spaced 0.5-3 mm apart, articulated at the base.
Flowers
Flower buds 4-6 mm long at anthesis, ellipsoid or globose; corolla appressed-tomentose in bud, the hairs porrect-stellate and multangulate; calyx sparsely to rather densely pubescent, the hairs partly long-, coarse-stalked, porrect-stellate and multangulate, stipitate-glandular at 6x magnification; calyx lobe sutures evident as lines of minute whitish hairs. Flowers all apparently perfect; calyx 4.5-7 mm long, lobed 1/2-3/4 way to the base, campanulate to stelliform, subcoriaceous, the tube 1.5-3.5 mm, the lobes 1.9-4.5 x 1.2-3 mm in flower, oblong to acute, stipitate-glandular and sparsely to rather densely pubescent abaxially, the hairs sessile, short- and relatively long- and multiseriate-stalked, porrect-stellate and multangulate, glabrous or somewhat stipitate-glandular adaxially; fruiting calyx somewhat accrescent, the lobes 2.7-6.8 x 1.6-4.4 mm. Corolla 1-1.5 cm in diameter, 6-11 mm long, inserted to strongly exserted from calyx at anthesis, rotate-stellate, chartaceous, white, the tube 1.5-4 mm, the lobes 3.5-8 x 2.5-4.3 mm, ovate to lanceolate, acute at apices, densely pubescent to tomentose abaxially, the hairs mixed sessile, short-, and relatively long-stalked, porrect-stellate and multangulate, glabrous or occasionally sparsely pubescent toward apices adaxially, the hairs simple or few-rayed porrect-stellate and multangulate. Stamens with filaments 0.6-1.5 mm long, inserted on corolla tube 1-1.7 mm above the base, glabrous; anthers 1.8-3 (-3.4) x 0.7-1.1 mm, oblong, blunt-tipped, yellow, free, glabrous, dehiscing by large introrse apical-lateral pores that extend into longitudinal slits with age. Ovary conical, glabrous or sparsely pubescent, the hairs simple and sessile or short-stalked, multangulate; style 4-5 x 0.2-0.3 mm, terete, exserted from stamens, glabrous or with occasional simple or few-rayed multangulate hairs near base; stigma truncate to subcapitate.
Fruits
Fruit a fleshy berry, 0.8-1.1 cm in diameter, globose, obtuse at apex, yellow when ripe, glabrous.
Seeds
Seeds 1.2-2.1 x 1-1.7 mm, mostly reniform, deltoid or suborbicular, yellowish brown, the testa honeycombed, reticulate-punctate.
Flowering and fruiting year-round.
Common names. Costa Rica: zorillo.