Solanum monarchostemon
Citation:
Bull. Nat. Hist. Mus. London, Bot. 30: 23. 2000.
Type:
Ecuador. Pastaza: Puyo, Comunidad Santa Cecilia, Villano, 380 m, 1º30’S, 77º27’W, 1 May 1992, Palacios 10117 (holotype, QCNE; isotype, MO).
Last edited by:
Knapp, S.
Written by:
Knapp, S.
Habit:
Herbs to small shrubs, 0.5-1.3 m, single-stemmed; stems densely pubescent when young with uniseriate white trichomes, 0.5-2mm, later glabrescent; bark brown.
Sympodial structure:
Sympodial units plurifoliate.
Leaves:
Leaves 9-25 x 4-10 cm, elliptic, with 8-13 pairs of primary veins, pubescent above with scattered 4-5-celled, white, uniseriate trichomes 1-2 mm long on the veins and lamina, densely to sparsely pubescent beneath with 4-7-celled, white, uniseriate trichomes 1-2 mm long, only along the veins, not on the lamina, the trichomes denser on the new growth, mixed with papillate trichomes on new growth, occasionally uniseriate trichomes glandular, the gland a single cell.
Inflorescences:
Inflorescence 2 or 3 times branched from a single point, densely or more rarely sparsely pubescent with mixed papillate trichomes and uniseriate, white trichomes 1-3 mm long, these occasionally gland-tipped, the gland a single cell, the peduncle 4-9 cm, the branches 1-3 cm, each branch with a single flower open at a time, but with up to 100 scars on each branch. Buds pointed, pubescent with uniseriate white trichomes. Pedicels (3-)5-8 mm, sparsely pubescent with uniseriate trichomes like the inflorescence or with only papillate trichomes, deflexed.
Flowers:
Flowers with the calyx tube conical, 0.5-1 mm, the lobes deltate with lighter hyaline margins, 1-1.5 mm, without a distinct apical tuft of trichomes, sparsely to densely pubescent with uniseriate trichomes 0.5-2 mm long, these denser along the midline of each lobe; corolla white to greenish white, occasionally purplish tinged, 1.2-1.6 cm in diameter, lobed nearly to the base, the lobes planar at anthesis, 6-9 mm, narrowly triangular with pointed, strongly cucullate tips, papillate at the tips or with scattered uniseriate white trichomes on the abaxial surface; filament tube minute, c. 0.1-0.2 mm; long anther 4-4.5 x c. 1.5 mm, the filament 1-1.5 mm; middle anther pair 3-3.5 x c. 1 mm, the filaments c. 1 mm; small anther pair 2.5-3 x c. 1 mm, the filaments c. 0.5 mm; ovary conical, glabrous; style 5-6 mm, glabrous, the stigma flattened capitate.
Fruits:
Fruit globose, 0.8-1.4 cm in diameter, green with four darker stripes, smooth, the pericarp thin and brittle when dry; fruiting pedicel 0.8-1.8 cm, erect, or slightly deflexed from the weight of the fruit.
Seeds:
Seeds 5-10(-15) per fruit, 3-3.5 mm long, pale tan or reddish, flattened to ovate-reniform, the testa cells sinuate in outline, with markedly and regularly striate outer cell walls.
Chromosome number:
Not known
Distribution:
In Amazonian Colombia, Ecuador and Peru, usually growing in terra firme (non-flooded) forests, 100-450 (-1300) m.
Phylogeny:
Solanum monarchostemonum is a member of the Solanum thelopodium species group, an isolated, well supported clade in the genus (Bohs, 2005).
References:
Knapp, S. 2000. Revision of the Solanum thelopodium species group (section Anthoresis sensu Seithe, pro parte): Solanaceae.
Bull. Nat. Hist. Mus., London (Bot.) 30: 13-30.
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.
Solanum monarchostemon is sympatric with S. thelopodium over nearly its entire range, but does occur higher in the E Andean foothills than the latter. Label data indicate that where the two species do co-occur (i.e. Yasuni, Ecuador; Yanamono, Peru), S. monarchostemon occurs in upland, non-inundated forests, while S. thelopodium occurs in flooded forests. In areas where the two species grow together, intermediates do not appear to occur. To date (Knapp, 2000), no mixed collections of the two taxa have been seen, indicating their distinguishability to field collectors. More detailed demographic and population level studies on these species in areas of sympatry may shed additional light on these patterns.