Ipomoea argentea Meisn. in Martius et al.

Wood, John R. I., Munoz-Rodriguez, Pablo, Williams, Bethany R. M. & Scotland, Robert W., 2020, A foundation monograph of Ipomoea (Convolvulaceae) in the New World, PhytoKeys 143, pp. 1-823 : 1

167. Ipomoea argentea Meisn. in Martius et al. , Fl. Brasil. 7: 247. 1869. (Meisner 1869: 247)

Ipomoea villosa var. argentea (Meisn.) Hallier f., Jahrb. Hamb. Wiss. Anst. 16: 53. 1899. (Hallier 1899a: 53). Type. Based on Ipomoea argentea Meisn.

Batatas villosa Choisy in A.P. de Candolle , Prodr. 9: 337. 1845. (Choisy 1845: 337). Type. BRAZIL. São Paulo, Ytu, Martius 609 (lectotype M0184921, designated here).

Ipomoea villosa (Choisy) Meisn. in Martius et al. , Fl. Brasil. 7: 244. 1869. (Meisner 1869: 244), nom. illeg., non Ipomoea villosa Ruiz & Pav. (1799) .

Exogonium villosum (Choisy) Peter , Die Natürlichen Pflanzenfamilien 4 (3a): 28. 1897 [pub. 1891]. (Peter 1891: 28).

Ipomoea comosa House , Ann. New York Acad. Sci. 18: 201. 1908. (House 1908b: 201). Type. Based on Ipomoea villosa (Choisy) Meisn. (House 1908b: 201) .

Ipomoea stachyoides Meisn. in Martius et al. , Fl. Brasil. 7: 240. 1869. (Meisner 1869: 240). Type BRAZIL. Goiás, W.J. Burchell 6586 (holotype BR00005792245, isotypes K, P).

Ipomoea hypoleuca Taub. , Bot. Jahrb. 21: 449.1895. (Taubert 1895: 449). Type. BRAZIL. Goiás, Serra Dourada, E. Ule 3013 (holotype B†, isotype HBG506563).

Ipomoea argentea var. hypoleuca (Taub.) Hallier f., Jahrb. Hamburg. Wiss. Anst. 16 (3): 19. 1899. (Hallier 1899a: 53).

Type.

BRAZIL. Goyas et Piauhy: G. Gardner 3356 (lectotype BR0000005837519, designated by Wood et al. 2015: 74, isolectotype K).

Description.

Erect perennial, stem stout and somewhat woody, often simple, white-tomentose, 0.3-1 m high. Leaves subsessile, 2.5-10(-14) × 2-3.5(-5.5) cm. broadly oblong to oblong-elliptic, acute and sometimes mucronate, cuneate to rounded at base, densely sericeous or tomentose on both surfaces, adaxially greenish, abaxially grey; petioles 0-5 mm. Inflorescence terminal, formed of sessile or shortly pedunculate compact cymes from the upper leaf axils, cymes commonly single-flowered but sometimes with 2-10 flowers; peduncles 0-2.5 cm, tomentose; bracteoles linear-lanceolate to ovate, up to 10 × 5 mm, hirsute, somewhat persistent; pedicels 1-3 mm; sepals subequal, 7-9 mm, elliptic, obtuse, coriaceous, convex, brown when dry, the outer villous but glabrescent, inner glabrous; corolla 5-6 cm long, funnel-shaped, pink, glabrous, limb c. 4 cm diam., distinctly lobed. Capsules glabrous, ellipsoid, 8 × 6 mm, very shortly rostrate; seeds c. 3 mm, long-pilose.

Illustration.

Austin (1998: 401); Figures 6C , 8A , 98 .

Distribution.

A characteristic species of cerrado in Brazil extending to Paraguay, Brazil and to the llanos of Venezuela and Colombia.

PARAGUAY. Amambay: Rojas in Hassler 10055 (BM, K).

BRAZIL. Dist. Fed.: Rio São Bartolomeu, E.P. Heringer et al. 6100 (IBGE, K); Burração, G. Kirkbride 3967 (K). Goiás: E.P. Heringer 10859 (UB); Chapada da Veadeiros, J.R. Pirani et al. 1827 (MO, USP, K); G. Gardner 3908 (K); summit of Cerro Dourada, 20 km SE of Goias Velho, H.S. Irwin et al. 11728 (FTG, NY) - var. hypoleuca ; Rio dos Couros, A.F.M. Glaziou 21786a (P) - var. hypoleuca. Mato Grosso: Novo Mundo, Parque Est. Cristalino, D. Sasaki et al. 2125 (K); Rio Brilhante, G. Hatschbach 26119 (MBM, RB). Minas Gerais: Campina Verde, A. Macedo 249 (BM); Patrocínio, Morro da Pedras, H.S. Irwin et al. 25462 (NY), Belo Horizonte, F.C. Hoehne 3064 (F, SP); Caldas, J.F.Widgren in A.F. Regnell 225 (K, S); A.F. Regnell III 193 (S). Paraná: P. Dusen 14932 (S), 16383 (S); Jaguariaiva, G. Hatschbach 52795 (MBM). São Paulo: Rawitscher s.n. [1/3/1945] (SPF, K); A.C. Brade 5567(S). Mato Grosso do Sul fide Flora do Brasil (2020).

BOLIVIA. Santa Cruz: Ángel Sandoval, Santo Corazón, Cerro Pelón, J.R.I. Wood et al. 25639 (USZ). Velasco, P.N. Noel Kempff Mercado, R. Guillén & T. Centurion 845 (ARIZ, BOLV, F, FTG, MO, NY, USZ); J.R.I. Wood et al. 25244 (K, LPB, UB, USZ).

COLOMBIA. Caquetá: J.C. Betancour 1928 (COL). Casanare:. Saravia 2705 (COL). Meta: L. Uribe 1346 (COL). Vaupés: J.M. Idrobo 9460 (COL).

VENEZUELA. Amazonas: J. Steyermark et al. 131513 (MO); Wessels Boer 1925 (NY); Bolívar: J. Steyermark et al. 131713 (MO). Orinoco: Maypures, Spruce 3605 (BM, K).

Note.

A very distinct species because of its erect habit, subsessile silvery leaves and lobed corolla.

Variation.

Despite its distinctiveness this species is quite variable and this is reflected in our molecular results which suggest that it is not monophyletic although it is difficult in the present state of our knowledge to reconcile molecular results with morphology. The majority of the specimens including the lectotype have leaves dull green adaxially and grey abaxially (Wood et al; 2015: 73 (Figure 22B). However, some specimens have more lustrous sericeous leaves similar to the original syntype Spruce 3605 (Wood et al. 2015: 73, figure 22A). Further investigation is required to assess whether these forms are of taxonomic significance. Var. hypoleuca is especially distinct and is often recognised, sometimes as a distinct species. It is an erect herb with leaves 3-5 × 1.2-3 cm, ovate, adaxially green, shortly tomentose but abaxially densely white-tomentellous. It is restricted to Goiás in the Brazilian planalto.

Figures

Figure 6. Sepals of Ipomoea species. A I. argyreia B I. tricolor C I. argentea D I. syringiifolia E I. eriocalyx F I. procurrens G I. tarijensis H I. regnellii. Photographs of A (Mendoza 4899); C (Mendoza 4705) and F (Mendoza 4900) by Moises Mendoza; B (Wood & Soto 27960) and H (Wood & Soto 27951) by Daniel Soto; D by Hector Keller; E (Wood et al. 27809) by Beth Williams; G (Wood 27920) by John Wood.

Figure 8. Corollas showing variations in form (side view), size, limb lobing and stamen exsertion. A Ipomoea argentea B I. repanda C I. neei D I. electrina E I. habeliana F I. santillanii G I. nationis H I. rubriflora J I. longistaminea K I. megapotamica L I. megalantha M I. neriifolia N I. syringifolia P I. ramosissima Q I. elongata R I. mucronatoproducta. A from Wood et al. 25639 and photo; B from Whitefoord 5244; C from Skutch 2043; D from Breedlove 27626; E from Bentley 203; F from Bourgeau 3024; G from Saunders 987; H from Wood et al. 27678; J from Pastore et al. 2678; K from Wood et al. 28060; L from Hassler 9114; M from Rezende et al. 1011; N from Stutz 1426 and photo; P from Bang 2246; Q from Purpus 3904; R from Wood & Villarroel 25474. Drawn by Rosemary Wise.

Figure 98. Ipomoea argentea. A habit B stem and leaves C adaxial leaf surface D abaxial leaf surface E calyx F outer sepal G middle sepal H inner sepal J corolla opened out to show stamens K ovary and style. Drawn by Rosemary Wise A, E-K from Wood et al. 25639; B-D from Ratter et al. 2830.