Solanaceae Source

A global taxonomic resource for the nightshade family

Solanum okadae

Citation author: 
Hawkes & Hjert.
Citation: 
Bot. J. Linn. Soc. 86: 414. 1983.
Type: 
Bolivia. La Paz: Prov. Inquisivi, 0.5 km from Quime on road to Inquisivi, 3060 m, 14 Mar 1981, J. G. Hawkes, I. Avilés, and R. Hoopes 6727 (holotype, K000005818; isotypes, BAL, C, K000439371).
Last edited by: 
Spooner, D.M.
Written by: 
Spooner, D.M.
Habit: 
Herbs 20-80 cm tall, erect. Stems 2-4 mm in diameter at base of plant, green, sometimes green and purple mottled, unwinged or with very narrow wings, subglabrous with very short hairs or with 2-3-celled whitish hairs; tubers typically borne singly at the end of each stolon.
Sympodial structure: 
Sympodial units tri- to plurifoliate, not geminate.
Leaves: 
Leaves odd-pinnate, the blades 8-19 x 7-14 cm, green, membranous to chartaceous, subglabrous adaxially and abaxially, with hairs like those of the stems; lateral leaflet pairs 1-2, greatly decreasing in size toward the leaf base, with the terminal leaflet larger than the laterals, sometimes greatly so; most distal lateral leaflets 4.3-8.2 x 2.1-4.1 cm, ovate to elliptic, the apex acute to acuminate, the base cordate to truncate to cuneate; terminal leaflet 5.5-12 x 3.5-8 cm, broadly elliptic to ovate to suborbicular, the apex acute to acuminate, the base cordate to truncate to cuneate; interjected leaflets absent, petiolules 3-5 mm; petioles 2-4 cm, pubescent as the stems. Pseudostipules absent and extremely small or scale-like, or lunate and up to 8 mm long, pubescent with hairs like those of the stem.
Inflorescences: 
Inflorescences 4-10 cm, terminal with a subtending axillary bud, generally in the distal half of the plant, usually forked, with 2-6 flowers, with all flowers apparently perfect, the axes pubescent with hairs like those of the stem; peduncle 2-4.5 cm long, subglabrous with hairs like the stem; pedicels 20-30 mm long in flower and fruit, spaced 1-10 mm apart, articulated high in the distal third.
Fruits: 
Fruit a globose berry, ca. 1-2 cm in diameter, green, glabrous.
Seeds: 
Seeds from living specimens ovoid and ca. 2 mm long, whitish to greenish in fresh condition and drying brownish, with a thick covering of “hair-like” lateral walls of the testal cells that make the seeds mucilaginous when wet, green-white throughout; testal cells honeycomb-shaped when lateral walls removed by enzyme digestion.
Chromosome number: 

2n = 2x = 24 voucher: Ochoa & Salas 15506 (CUZ, NY) (Hijmans, et al. 2007)

Distribution: 

Solanum okadae is endemic to Bolivia (Depts. La Paz, Cochabamba, Chuquisaca), growing in sunny fields, cultivated fields, among bushes, or in shade of trees, in rocky soils of rich soils; 2450-3200 m in elevation.

Phenology: 
Flowering collections made from February to March.
Phylogeny: 

Solanum okadae is a member of Solanum sect. Petota Dumort., the tuber-bearing cultivated and wild potatoes. Within sect. Petota, Solanum okadae is a member of a very diverse clade related to the cultivated potato. On a higher taxonomic level, it is a member of the informally-named Potato Clade, a group of perhaps 200-300 species that also includes the tomato and its wild relatives (Bohs, 2005).

Commentary: 

Hawkes and Hjerting (1983) described S. okadae on the basis of specimens from Bolivia, (Depts. Cochabamba and La Paz) and from Argentina (Provs. Jujuy and Salta), they failed to cite collections from Argentina. Hawkes and Hjerting (1989) stated that that they originally thought that S. okadae was vigorous and tall, although in its natural habitat it formed small tufts or semi-rosettes with simple leaves or leaves with only one set of lateral leaflets. Hawkes (1990) stated that S. okadae, S. venturii and S. microdontum were closely related species, but S. venturii could be distinguished from S. okadae by the larger terminal and smaller lateral leaflets.

Ochoa (1990), when comparing S. venturii and S. microdontum, stated that S. venturii is taller, more vigorous, larger-flowered and more pubescent than S. microdontum, and stated that the true affinity of S. microdontum is with S. okadae because both present a large terminal leaflet of similar shape, and have sparsely pilose and poorly dissected leaves.

Clausen and Ispizúa (2005), when comparing the disjunct populations of S. okadae from Bolivia and from Argentina found that the Bolivian accessions of S. okadae could be differentiated from the Argentinean populations on the bases of larger leaves, larger peduncle, larger calyx, winged stem, and more pairs of lateral leaflets. We identify the Argentinean populations thought to be S. okadae as S. venturii and the Bolivian populations as S. okadae.

Van den Berg and Groendijk-Wilders (2007), included a few populations of S. okadae and S. venturii from Argentina and S. okadae from Bolivia in a wider morphological and AFLP study. Their morphological analysis was not consistent, but their AFLP study showed that the Argentinean populations of S. okadae and S. venturii clustered together while S. okadae from Bolivia formed a distinct group. Solanum okadae can be identified by its white rotate to rotate pentagonal corollas, Leaves sparsely pubescent, generally smaller than S. microdontum, 2-4 mm wide at base, and plants 20-80 cm tall; leaves 7-14 cm wide; in contrast to plants 18-25 cm tall; leaves 4.8-7 mm wide; as in S. venturii.

References: 

Hawkes, J.G. & J.P. Hjerting 1983. New tuber-bearing Solanum taxa from Bolivia and northern Argentina.
Bot. J. Linn. Soc. 86: 405-417.

Hawkes, J.G. & J.P. Hjerting 1989. The potatoes of Bolivia: their breeding value and evolutionary relationships.
Oxford University Press, Oxford.

Hawkes, J.G. 1990. The potato: evolution, biodiversity and genetic resources.
Oxford: Belhaven Press.

Clausen A.M. & V.N. Ispazúa 2005. Caracterización morfológica de Solanum okadae.
XXX Jornadas Argentinas de Botánica, Rosario, Córdoba, Argentina. Actas en el Boletín de la Sociedad Argentina de Botánica. 40: 59.

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.

Van den Berg, R.G. & N. Groendijk-Wilders 2007. AFLP data support the recognition of a new tuber-bearing Solanum species but are uninformative about its taxonomic relationships.
Pl. Syst. Evol. 269: 133–143.

Hijmans, R., T. Gavrilenko, S. Stephenson, J. Bamberg, A. Salas & D.M. Spooner 2007. Geographic and environmental range expansion through polyploidy in wild potatoes (Solanum section Petota).
Global Ecol. Biogeogr. 16: 485-495.

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