Vigna schottii, (Benth.) A. Delgado & Verdc.

Delgado-Salinas, Alfonso, Lavin, Matt, Snak, Cristiane & Lewis, Gwilym P., 2022, Systematics of Vigna subgenus Lasiospron (Leguminosae: Papilionoideae: Phaseolinae), Systematic Botany (Basel, Switzerland) 47 (1), pp. 97-124 : 117-118

6. VIGNA SCHOTTII (Benth.) A. Delgado & Verdc. , in American Journal of Botany 98(10): 1711 (2011).

Phaseolus schottii Benth., Comm. Legum. Gen. : 75 (1837).

TYPE: BRAZIL. ad Tejuco . Schott s.n. (holotype: W !; isotype: NY! ). non P. schottii Benth. sensu Hassler in part, Candollea 1: 463. 1923; non P. schottii var. longifolius (Benth.) Hassl., Candollea 1: 463. 1923; non P. schottii var. longifolius forma intermedius Hassl., Candollea 1: 463. 1923; non P. schottii var. longifolius forma grandiflorus Hassl., Candollea 1: 464. 1923; non P. schottii var. campestris Hassl., Candollea 1: 464. 1923; non P. schottii var. campestris forma braziliensis Hassl., Candollea 1: 464. 1923; non P. schottii var. campestris forma guyanensis Hassl., Candollea 1: 464. 1923; non P. schottii var. campestris forma transiens Hassl., Candollea 1: 464. 1923; non P. schottii var. tucumanensis Hassl., Candollea 1: 464. 1923. (See notes).

Phaseolus ovatus Benth., Comm. Legum. Gen. : 75 (1837). Syntypes. BRAZIL. “In campis et pascuis ad Para” Martius s.n. (not traced). “Ad Tejuco”, Schott s.n. (NY!), synon. nov. (See notes).

Phaseolus ovatus Benth. var. glabratus Benth. , sensu Chodat & Hassler, Bull. Herb. Boiss. Ser. 2, 4: 909. (1904).

Phaseolus schottii var. genuinus Hassl., Candollea 1: 463. 1923. Syntypes. BRAZIL. Blanchet 58 (G!, P! = V. trichocarpa ); Salzmann 181 (G! = V. trichocarpa ); PARAGUAY. Hassler 1818 (G, not seen); Hassler 5892 [5982] (NY!, US! = V. schottii ); Hassler 6465 (not seen); Hassler 6743 (G!; NY!; P!; US! = V. schottii ); Rojas 477 (G, not seen). Phaseolus schottii var. genuinus forma ovatus Hassl., Candollea 1: 463. 1923. Syntypes. BRAZIL. Salzmann 183 (G! pro parte; P-3! = V. trichocarpa ); Blanchet 1159 (G, not seen); URUGUAY. Berro 843 (G, not seen); Osten 4671 (G, not seen); PARAGUAY. Balansa 1548 (G-3!, P-3! = V. longifolia ); Hassler 1818a (G, not seen); Hassler 6465a (G, not seen); Hassler 8470 (G-3!; K!; NY!; US!; W! = V. schottii ); Hassler 9352 (G, not seen). Specimens reported to be at G were not found in the collection. This varietal name genuinus was found to comprise more than one taxon.

Perennial (?), trailing and climbing herbaceous vine, up to 1.5 m, with fibrous roots ca. 50 cm long, foliage and reproductive parts covered with minute glandular hairs, and yellowish-white, straight hairs. Stems slender, fibrous, often with adventitious roots, sparsely to densely pilose or often hirsute, with yellowish or white hairs, ca. 2 mm long. Leaves with stipules lanceolate, distinctly spurred, upper portion 5–10 ˟ ca. 1 mm, 6-veined; lower portion ca. 2 mm long, pilose to densely strigose; stipels ovate-lanceolate, 1.5–2 mm long, subequal in length to petiolules, covered with minute glandular trichomes; petioles 2.4–6 cm long, hirsute with retrorse hairs, rachis considerably shorter, 5–10 mm long, with some antrorsely appressed hairs, canaliculate; leaflets ovate to ovate-lanceolate, usually acute at apex, with raised veins below, chartaceous and sparsely to densely sericeous, terminal leaflet 4.2–10 ˟ 2–4 cm, lateral leaflets 4–7.8 ˟ 1.8–4.2 cm. Inflorescences up to 11 cm long, peduncles 5–9 cm long, almost entirely covered with short retrorse hairs, densely strigose distally; rachis 1.5–2 cm long, with 3–5(–8) swollen, obpyriform nodes, 2.5–3 mm long, each with 4–6 alternate orifices, flowers clustered distally; primary bracts caducous, secondary bracts ca. 6 mm long, caducous; bracteoles mostly persistent at anthesis, ca. 6 mm long, longer than calyx-tube, bracts and bracteoles lanceolate and at base geniculate; pedicels shorter than calyx tube, longer and twisting in fruit, covered with retrorse, straight hairs; calyx campanulate, sparsely strigose at the base, glabrescent distally, tube longer than teeth, ca. 4 mm long, teeth triangular, subequal, 1–2 mm long, the adaxial pair broad and emarginate, lateral teeth slightly longer than lower tooth. Flowers described as golden yellow, ca. 1.5 cm long; standard broadly ovate, 1.2–1.4 ˟ 1.4–1.6 cm, bilobed at apex, with two parallel callosities on the lamina above the point of folding, the left one more prominently developed, and two fleshy auricles above the claw, claw ca. 3 mm long; wing petals longer than keel, with an obovate lamina, ca. 1.5 cm long, 8–10 mm wide, with an auricle at base, claw ca. 2 mm long; keel beaked, curved through ca. 270, 1.2–1.4 cm above the wing, with a transverse pocket above the petal claws, the claws ca. 3 mm long, fused to staminal tube, androecium with staminal tube ca. 2 cm long, vexillary stamen with a basal appendage; anthers ovate, ca. 0.5 mm long, basifixed to sub-basifixed to filaments; pollen grains triporate, with a coarsely reticulate exine; ovary straight, with a basal nectary disc less than 1 mm long, ovules 9 per ovary, style with a tenuous lower part, upper portion thickened, cylindrical, curved, pollen brush 3–4 mm long, with long-spreading hairs, produced beyond the stigma to form a short hook; stigma transversally-ovate, laterally placed. Fruit patent or rarely ascending, oblong, subcylindrical, valves thin-walled, not constricted between the seeds, turning dark brown or black at maturity, densely strigose, with golden yellow, straight hairs, 4–6 cm long, ca. 6 mm wide, elastically dehiscent, beak straight, 3 mm long. Seeds (immature) D-shaped, surface smooth, testa brown, hilum oblong, as long as seed width, covered by an epihilum, and with variable aril development.

Illustrations — Burkart (1987), as Vigna longifolia ; Hoc et al. (1993) as Vigna longifolia ; Ferrucci et al. (2002) as Vigna longifolia .

Distribution and Habitat —This species ranges across the provinces of Corrientes, Entre Rıos, and Misiones in Argentina. In Paraguay it occurs mainly in the River Paraguay basin, and it is disjunct in El Beni, Bolivia and in the states of Espırito Santo, Rio de Janeiro, and possibly ranges south to Rio Grande do Sul, in Brazil ( Fig. 3 ). The species occurs in woodland margins, along the shores of lakes or temporary ponds and riverbanks, and low swampy grasslands or “pajonal,” below 200 m. Flowering and fruiting throughout the year.

Etymology —Named in honour of H. W. Schott, who collected in Brazil.

Vernacular Name —“Feij ~ ao biriba.”

Representative Specimens Examined —See Appendix 1 for complete list. Argentina. — CORRIENTES: Depto. Ituzaingo, Isla Apipe Grande, Puerto San Antonio, 8 Dec 1973, A. Krapovickas 23806 (MO). Bolivia. — EL BENI: Yacuma Province, unos 60 km al E de San Borja, 22 Jul 1989, St. G. Beck 16929 (LPB, MEXU). Paraguay. — ALTO PARAGUAY: swamp bordering Rıo Tapiracuai, 11 Sep 1957, A. L. Woolston 872 (K, NY).

Notes —Bentham’ s (1837) original description of Phaseolus ovatus was based on two specimens: in campis et pascuis ad Para collected by Martius s.n. and ad Tejuco [Tijuca, Rıo de Janeiro] collected by Schott s.n., neither of which has been found in any of the herbaria visited or consulted by Bentham. However, there is a specimen at K which has long been considered the type of P. ovatus . The herbarium sheet has a label that reads Pohl (not Schott) as the collector of this plant in Tejuco, Brazil. In addition, there are two comments in pencil, one in Bentham’ s handwriting, in the left bottom corner identifying it as P. ovatus , and the other by Piper annotating it as, “possibly the type of P. ovatus ”. Regarding the confusing information about Pohl and Schott’ s collections, Urban (1899) in Flora Brasiliensis pointed out that, “It is a matter for grieving because which specimens Pohl [and] which specimens Schott might have collected cannot always be settled from the sheets of the Vienna herbarium”. Nonetheless, the specimen has spurred stipules, as mentioned in the description of Phaseolus schottii . Concurrently, Bentham (1837) distinguished an unnamed variety of P. ovatus , the type of which, at M, was identified as Vigna luteola (Jacq.) Benth. by Verdcourt (1970). This leaves the description as the only extant original material. In addition, Bentham (1859), in Flora Brasiliensis , listed under P. ovatus seven specimens, including another variety: var. glabratus , the type of which at M is conspecific with what is currently known as V. trichocarpa . Of the other six, two are the Martius and Schott collections cited in the original protologue, as well as the taxon mentioned above as an unnamed variety. Of the remaining three Brazilian specimens cited under P. ovatus , two: in humidis Banda Oriental frequens, Tweedie s.n. (K), and in Brasilia meridional, A. de St. Hilaire s.n. (P), are plants like Phaseolus diffusus (= Vigna diffusa of this treatment) and the third, collected in Rıo Grande do Sul, Herb. Imp. Br. 1536 (P), is here treated as Vigna schottii . Without extant syntypes, and the material cited in Flora Brasiliensis under P. ovatus being heterogeneous, different taxonomic interpretations have been given by authors dealing with this species name. We suggest that the name should be abandoned as it seems impossible to establish its identity.

Accordingly, the range of Vigna schottii extends to southern Brazil, which is a possibility. In the absence of any other collections from that area, we suspect there may have been a mistake in specimen labelling.

Hassler (1923) included a number of diverse elements within his concept of Phaseolus schottii , held together by their straight-beaked pods and sparsely hirsute-pilose to glabrescent calyces, characteristics common in V. subg. Lasiospron . Most of the infraspecific taxa described under P. schottii by Hassler are morphologically heterogeneous and difficult to interpret.

As discussed previously, Vigna schottii and V. diffusa share some morphological characters although V. schottii is much more robust, and its leaves are commonly ovate-lanceolate, and its stipules are spurred (while those of V. diffusa are biauriculate). Vigna schottii also shares some characteristics with V. trichocarpa as well; some forms of V. schottii in central eastern Brazil have narrower leaflets similar those of V. trichocarpa . The fruits of V. schottii , however, are narrower and longer than those of V. trichocarpa , in addition to being held pendent on the infructescence.

Figures

FIG. 3. Geographic distributions of the six species of Vigna subg. Lasiospron, which are ordered, top to bottom, by mean latitude. Filled circles indicate species with amphi-Atlantic distributions.