Vigna juruana, (Harms) Verdc., Kew

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 : 107-110

1. VIGNA JURUANA (Harms) Verdc., Kew Bulletin 24: 540 (1970). Phaseolus juruanus Harms, Notizbl. Bot. Gart. Berl. 7: 506 (1921). TYPE: BRAZIL. Amazonas, Jurua miry, Jul 1901, E. Ule 5533 (holotype: B, presumably destroyed; isotypes: K!, U!). Figure 7 .

Phaseolus campestris sensu Benth. , in Mart., Flora Brazil. 15(1): 188 (1859). TYPE: BRAZIL. “in Braziliae septentrionalis campis et pascuis ad Para.” Martius s.n. (lectotype M!, designated here), nom. illeg., non P. campestris Benth., Comm. Legum. Gen. : 77 (1837), non Vigna campestris (Mart. ex Benth.) R.Wilczek , in Fl. Congo Belge 6: 391 (1954). See nomenclatural notes below.

Phaseolus schottii var. campestris forma brasiliensis Hassl., Candollea 1: 464. 1923. TYPE: BRAZIL. “Alto Amazonas: ad ostium fluminis Saliman [sic]”, Spruce 1641 (lectotype: K, herb. Benth., designated here; isolectotypes: G, K!, M!), synon. nov., non P. schottii var. campestris forma guyanensis Hassl., Candollea 1: 464. 1923. TYPE: FRENCH GUIANA. Poiteau s. n. (holotype: G), synon. nov., non P. schottii var. campestris forma transiens Hassl., Candollea 1: 464. 1923. TYPE: BRAZIL. Bahia in pratis humidis, Salzmann s.n. (holotype: G; isotypes: K!, MO!). See nomenclatural notes below.

Phaseolus schottii Benth. var. tucumanensis Hassl., Candollea 1: 464 (1923). Type: Argentina. Tucuman, cumbre de Anfama, alt. 2500 m, Schreiter 866 (holotype: Herb. Osten, not seen). See nomenclatural notes below.

Perennials or annuals (?), procumbent or climbing vines up to 3 m, with foliage and reproductive parts covered with minute glandular hairs, and sparse or dense pubescence. Stems hollow, slightly woody at base, often with adventitious roots, sparsely to densely strigose, with yellow to reddish, retrorse hairs. Leaves with stipules ovate to narrowly-lanceolate, unequally bilobed, upper portion ca. 3 mm long, 1–2 mm wide, 5–6-veined, not reflexed, persistent; lower portion ca. 2 mm long, sparsely pilose; stipels oblong or triangular, ca. 1 mm long, subequal in length to petiolules, glabrous except for minute glandular trichomes; petioles 3.5–11 cm long, covered with retrorse hairs, rachis considerably shorter, ca. 0.5–2.5 cm long, with some antrorsely appressed hairs on the adaxial side, canaliculate; leaflets entire, ovate to narrowly ovate, or lanceolate, acute at apex, with raised veins below, membranaceous, sparsely to densely strigose, terminal leaflet 4–12 3 1.5–9 cm, lateral leaflets 4.5–10.5 3 2–7 cm. Inflorescences up to 15 cm long, peduncles ca. 13.5 cm long, covered with short retrorse hairs, densely strigose distally; rachis 1.5–2 cm long, with 5–8(–10) swollen, oblong, 2–3 mm long nodes, 5–8 orifices alternately distributed, flowers clustered distally; primary bracts caducous, secondary bracts ca. 6 mm long, caducous; bracteoles mostly persistent at anthesis, ca. 4.5 mm long, longer than calyx tube; pedicels shorter than calyx tube, 1–1.5 mm long, longer and twisting in fruit, covered distally with straight, retrorse hairs; calyx campanulate, sparsely strigose at the base, glabrous distally, ca. 2 3 ca. 1.5 mm, upper teeth slightly divided, narrow and acute, not forming a lip, teeth triangular, subequal, 0.5 mm long, lower tooth slightly longer than lateral teeth. Flowers pale greenish yellow, 8–10 mm long; standard petal asymmetric, broadly ovate, ca. 8 3 ca. 8 mm, bilobed at apex, two parallel callosities on the lamina above the point of folding, two fleshy auricles above a short claw; wing-petals longer than keel, with an obovate lamina, ca. 1 cm long, 5–6 mm wide, with an auricle at base, claw ca. 3 mm long; keel distinctly beaked, twisted through ca. 270, the apex hook-like; ca. 7 mm above wing petals, with transverse pockets above the claws, claws ca. 2 mm long, fused to staminal tube; androecium ca. 1 cm long, vexillary stamen with a basal appendage; anthers oblong-ovate, ca. 1 mm long, basifixed to sub-basifixed to filaments; pollen grains triporate, with a coarsely reticulate exine; ovary straight, with a basal nectary disc ca. 0.5 mm long, ovules 8–9 per ovary, style with a tenuous lower part, upper portion thickened, cylindrical, curved, pollen-brush ca. 1 mm long, with curled hairs; stigma globose, apical. Fruit patent, linear-oblong to slightly falcate, flattened, valves thin-walled, not constricted between the seeds, turning dark brown or black at maturity, 4–7 cm long, 4–7 mm wide, elastically dehiscent, sparsely strigose, with yellow, straight hairs, beak 1 mm long, straight. Seeds D-shaped, 3.5–6.5 3 3–4 mm, surface smooth, testa dark brown, mottled lighter brown, hilum oblong, as long as seed width, rim-aril distinctly raised, covered by an epihilum, without aril. Figure 7 .

Illustrations —Wilczek (1954) as Vigna campestris ( Fig. 7 ).

Distribution and Habitat —Southern Mexico (Tabasco), Central America ( Costa Rica, Honduras, Panama), and South America ( Bolivia, Brazil, Colombia, Ecuador, Guyana, French Guiana, Suriname); also including Trinidad ( Republic of Trinidad and Tobago). Likely native in west and central Africa ( Cameroon, Democratic Republic of Congo, Central Africa Republic, and Nigeria; Fig. 3 ). Seasonal or permanently flooded plains or in riverine forests; in South America, in the Solim ~ oes River and Amazon River basin and eastern Restinga Atlantic Forest. Sometimes reported growing on the floodplains of Amazonian black water and clear water rivers (i.e. Igapo, common name “feij ~ ao do Igapo”), sprawling in floating plant islands or growing in old rice fields; altitudinal range mostly 0–700 m (collected at 1400–1600 m in the Peruvian Ucayalli Department). This species grows in habitats similar to V. trichocarpa and V. longifolia with which it is sometimes sympatric (e.g. Iquitos, Peru). Flowering and fruiting have been registered all year except for June.

Etymology —Named after the River Jurua in Brazil.

Vernacular Names —“Soematalan” ( Amshoff 1939); “feij ~ ao do Igapo” (Froes 21065); “frijolillo” ( Colombia); “namiata” ( French Guiana, Wayapi); “porotillo” ( Peru); “kwakwa” (Wilczek 1954).

Representative Specimens Examined — See Appendix 1 for complete list. Bolivia. — PANDO: Manuripi, a lo largo del arroyo Bay, entre el campamento Bay y La Poza, 17 Oct 1989, St. G. Beck 19433 ( MEXU). Brazil. — AMAPA: Rio Araguari, vicinity Camp 12, 1 10'60”S, 52 7'60”W, 30 Sep 1961, J. Murca Pires 51366 ( MICH, US). Colombia. — AMAZONAS: Leticia, Rıo Amazonas, Isla de Mocagua , frente del Vergel, Lago Resaca, 3 51'0”S, 70 15'0”W, 110–120 m, 3 Oct 1991, A. Prieto 92 ( MO). Costa Rica. — ALAJUELA PROVINCE: Los Chiles, R. V. S. Ca no ~ Negro, cuenca del Rıo Frıo , 10 53'18”N, 84 46'37”W, 60 m, 27 Sep 2000, L. Acosta et al.2772 (G). French Guiana. Cayenne, Saut Nacibo, 4 41'0”N, 52 59'0”W, 20 m, 25 Mar 1994, B. Bordenave 892 (K). Guyana. Essequibo Isl. - W Demerara, lower 7 km of Tiger Creek ; 6 30'0”N, 58 39'0”E, 15 m, 11 Dec 1992, T. W. Henkel 403 ( US). Honduras. — ATLANTIDA DEPARTMENT: Tela River near Puerto Sierra, 3 May 1903, P. Wilson 669 ( NY). Mexico. — TABASCO: a 300 m de la desviacion del Rıo Gonzalez, hacia Boca Grande, 14 Feb 1990, M. A. Mag- a na ~ A 2255 ( MEXU). Panama. — PANAMÁ PROVINCE: Fort Clayton , Canal Zone, 14 Jul 1966, J. D. Dwyer 4584 ( MEXU, MO). PERU. — HUÁNUCO DEPARTMENT: Estacion Experimental Agrıcola, 701 m, 4 Dec 1945, R. J. Seibert 2268 (F, US). Suriname. Lucie Rivier, 2–10 km below confluence of Cost Rivier, 225 m, 9 Sep 1963, H. S. Irwin 55541 ( NY). Trinidad. Nariva Swamp, E of Sand Hill, 5 Apr 1977, C. D. Adams 14246 (K). Venezuela. — AMAZONAS: Departamento Rıo Negro , Rıo Siapa , near base of Cerro Aracamuni, 1 39'0”N, 65 40'0”W, 4 Nov 1987, 250 m, R. Liesner 22785 ( MO). Cameroon. Bipinde, Urwaldgebeit, Dec. 1912, G. Zenker 4300 (M). Central African Republic. Left bank of Mambere R., near Bania, 26 Nov 1965, A. J. M. Leeuwenberg 7040 (K). Democratic Republic Of The Congo. Jangauellei, ile Esali II, 12 Jul 1988, J. Louis 10294 (K). Nigeria. River Old Calabar, 1863, G. Mann 2319 (K) .

Notes —In Martius Flora Brasiliensis, Bentham (1859) described Phaseolus campestris , a name already used ( Bentham 1837) and thus a later homonym and illegitimate under Article 53 of the International Code of Nomenclature for algae, fungi, and plants (Turland et al. 2018) and unavailable for use (Verdcourt 1970). Hassler (1923), while possibly considering that Bentham (1837) listed Phaseolus schottii before V. longifolia , published four varieties, P. schottii var. genuinus , P. schottii var. campestris , P. schottii var. longifolia , and P. schottii var. tucumanensis . Under P. schottii var. campestris, Hassler combined characters diagnostic of different taxa and, in consequence, listed specimens of different taxa under his new combinations. Under P. schotti var. campestris forma brasiliensis he cited three collections from Brazil: Minas, in silvis ad Salgado [sic.], Martius 1680 (M!), since identified as V. luteola (refer to Verdcourt 1970: 540); Alto Amazonas: ad ostium fluminis Saliman [sic], Spruce 1641 (G), identified here as V. juruana ; and a collection from Bahia by Salzmann 182 (G), here identified as V. trichocarpa . The exact locality of Spruce’ s specimen has been established by consulting the expedition notes in Spruce (1851–1855). He recorded his collection numbered 1641, collected in Solim oes ~ and Manaquiry, on June 1851, as a Phaseolus close to P. ovatus ( P. ovatus aff.). Such information only appears on one of the two sheets of Spruce 1641 at K (herb. Benth.), and we have designated this specimen as the lectotype of P. schottii var. campestris . Amshoff (1939) considered P. schottii var. campestris f. guyanensis Hassl. as a synonym of Phaseolus trichocarpus . Unfortunately, original material could not be found at P, and the description does not give enough information to elucidate its identity; therefore, we accept Amshoffs judgment here. Concerning the type of Phaseolus schottii var. campestris f. transiens Hassl. , see statements under Vigna trichocarpa in this treatment.

Vigna juruana has the smallest flowers of all Vigna subg. Lasiospron species and has a very distinctive style on its gynoecium. The style has a tenuous lower part, with a thicker, cylindrical, and curved upper portion, which becomes rather slender again towards the stigma. Its pollen brush is short and with unique curled short hairs. In addition, the style has no extension beyond the stigma, a characteristic seen in all other species of V. subg. Lasiospron .

We have not seen the type of Phaseolus schottii var. tucumanensis , and despite Hassler’ s lengthy description in the taxon protologue it is not obvious where it belongs taxonomically. Lackey (1983) placed this variety as a synonym of Macroptilium fraternum (Piper) Lackey. We tentatively place var. tucumanensis as a nomenclatural synonym under Vigna juruana . This is because the original description includes floral dimensions that best fit Vigna juruana (e.g. a small calyx ca. 2.5 cm long). However, the original description describes the fruits as ca. 2.5 cm long and 3 mm wide, and the fruit length is too small for V. juruana . Regarding the type locality, no herbarium specimen has been found with a collection locality in the Tucuman province that matches the protologue of Phaseolus schottii var. tucumanensis . Moreover, no V. subg. Lasiospron species, including V. juruana , is reported from such a high elevation. Vigna juruana and V. lasiocarpa are the two V. subg. Lasiospron species with the widest elevational ranges ( Fig. 4 ) with V. juruana occurring up to 1028 m and V. lasiocarpa up to 1731 m. The Tucuman collection locality and the reported altitude of 2500 m for var. tucumanensis are both exceptional for the subgenus ( Figs. 3–4 ).

Figures

FIG. 7. Illustration of Vigna juruana. A. Habit, natural size. A1. Portion of stem. A2. Portion of peduncle. B. Stipules, some indumentum omitted for clarity (3 6). C. Leaflet outlines to show variation. C-1. Close-up of trichomes on upper leaflet surface. D. Extrafloral nectaries on inflorescence node (3 6). E, E1. Standard petal, ventral (3 6) and dorsal view. F1, F2. Wing petals (3 6). G, G1. Keel petals (3 6), taken from floral buds and flower. H. Staminal tube and vexillary stamen free (3 6). I. Gynoecium (3 5) and stigma enlarged. J. Fruit, natural size. K. Seed, hilar view (3 9). Drawn from Plowman, Schultes & Tovar 6387 (habit and dissection); Henkel et al. 3153 (stipules); Steyermark 87773 (fruit); Hill 13046 (seed). Illustration by Pat Halliday.

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.

FIG. 4. Elevation and climate variables, the latter of which varied most among 427 georeferenced collection sites of Vigna subg. Lasiospron species. From the top panel, elevation (m), annual mean temperature (C), annual precipitation (mm), and precipitation seasonality, which is the coefficient of variation (CV) of mean monthly precipitation (i.e.values close to 100% indicate highly seasonal climates, whereas values less than 60% indicate more uniform monthly precipitation regimes throughout the year). Species are ordered, left to right, by average north to south latitude (corresponding to Fig. 3). For each boxplot, the horizontal bar indicates the median, the box encompasses 50% of the data points, the whiskers approximately 99% of the data, and individual points represent outliers.Filled diamonds indicate mean values.