Merremia hoehnei Petrongari & Sim.

Petrongari, Fernanda Satori & Simão-Bianchini, Rosângela, 2016, A new species of Merremia (Convolvulaceae) from São Paulo State, Brazil, Phytotaxa 268 (4), pp. 244-250 : 245

Merremia hoehnei Petrongari & Sim. -Bianch. sp. nov., Figs. 1 (A–G)–2.

Type:— BRAZIL. São Paulo: Caieiras, 25 January 1945, F. C. Hoehne s.n. (holotype SP-74032!, [two sheets]).

Ab omnibus speciebus generis trichomatibus simplicibus et trichomatibus stellatis 2–3-radiatis sparsis inmixtis differt. Affinis Merremiae hasslerianae ( Chodat 1905: 693) Hassler (1911: 151) sed foliis 3-foliolatis (non foliis simplicibus) differt; a M. digitata ( Sprengel 1825: 808) Hallier f. (1893: 552) var. elongata ( Choisy 1845: 337) D.F. Austin & Staples (1983: 484) sed foliis marginibus dentatis (non foliis marginibus integris) differt; a M. hirsuta O´Donell (1952: 275) sed indumento eglanduloso (non simplice et glanduloso) differt.

Prostrate subshrubs. Stem 2–3 mm diameter, green to wine colored; internodes 1–4.2 cm long; indumentum hirsute, hyaline, with simple trichomes mixed with scattered 2–3-rayed stellate trichomes equal in length, ca. 1 mm long. Petiole 2–5 mm, hirsute. Leaves palmately-compound, 3-foliolate; leaflets sessile, lateral leaflets 2–4.7 × 0.6–1.7 cm, central leaflet 2.8–5.6 × 0.8–2 cm, narrow-elliptic to elliptic or oblong, apex acute to obtuse, mucronate, base cuneate to attenuate, margins irregularly dentate, both surfaces hirsute, secondary venation craspedodromous to brochidodromous, ca. 10 pairs of alternate and subopposite secondary veins leaving midrib, prominent on abaxial surface. Inflorescence an axillar monochasium compound of 1–2 flowers; peduncle 0.2–2.2 cm, hirsute; bracteoles linear, 4–8 mm long, sparsely hirsute; pedicels 2–5 mm, sparsely hirsute. Sepals unequal, elliptic, acuminate; external sepals 2, 7–11 × 2–3 mm, sparsely hirsute, internal sepals 3, 11–12 × 4–6 mm, glabrous; corolla 2.5–3.3 cm long, campanulate-infundibuliform, white, glabrous; stamens 5, epipetalous, filaments slender with a wide glandular base, whitish, 0.7–1.2 cm long; anthers twisted or incurved, cream colored; pollen tricolpate; ovary glabrous; style 1, ca. 1.7 cm long, whitish; stigmas 2, globose, white. Fruit a globose light-brown colored capsule with rounded apex, sepals slightly accrescent, bent inwards.

Additional material examined (Paratype):— BRAZIL. São Paulo: Pedregulho, Parque Estadual das Furnas do Bom Jesus, Chapadão, elev. 982 m, 20º13’06.5” S 47º26’68.9” W, 20 Feb. 2013, M. Pastore, A. Francener, E. P. Fortes & E. E. Macedo 245 ( SP!).

Distribution and phenology:— Merremia hoehnei is known only from two collections from the Cerrado biome in São Paulo State —one collected 70 years ago, in the district of Caieiras, in an area of “campo cerrado”, and another recently collected in the district of Pedregulho, in the “Parque Estadual das Furnas do Bom Jesus”, in an area of “campo sujo”. These two specimens were collected in flower in January and February, and fruits were observed in February.

Etymology:—This new species is named after Frederico Carlos Hoehne, an outstanding Brazilian botanist, who was collector of the type material of the new species, Hoehne (1922) published one of the first works accepting Merremia as delimited by Hallier (1893), and was the founder of the “Instituto de Botânica”, where this study was conducted.

Conservation status: — According to the IUCN (2014) red list categories, Merremia hoehnei should be considered Data Deficient (DD) because it is only known from two collections, and the precise distribution of the species is not known. However, it is important to point that M. hoehnei probably occurs only in “campo cerrado”, one of the most threatened habitat in Brazil ( Klink & Machado 2005). We tried to recollect M. hoehnei in Pedregulho, in October 2013, but we could not find it, even though coordinates were provided. This information suggests that M. hoehnei is an annual species.

Figures

FIGURE 1. A–G. Merremia hoehnei. A. Habit; B. Leaf; C. Simple and 2-rayed stellate trichomes; D. External sepal; E. Internal sepal; F. Corolla (longitudinal section) showing adnate androecium; G. Gynoecium. H–K. Merremia digitata var. elongata. H. Leaf; I. 6–10-rayed stellate trichomes; J. External sepal; K. Internal sepal. [A–G from Hoehne s.n. (SP 74032!), H–K from Gehrt s.n. (SP 31757!)]; drawing by Klei R. Sousa.