Eriosema heterophyllum Benth.

Authority

Acevedo-Rodríguez, Pedro. 1993. Systematics of Serjania (Sapindaceae) Part I: A Revision of Serjania Sect. Platycoccus. Mem. New York Bot. Gard. 67: 1-91.

Family

Fabaceae

Scientific Name

Eriosema heterophyllum Benth.

Description

Species Description - Prostrate herb to 1 m in length, with slender procumbent or decumbent stems from woody base, the stems albo- or rufo-pilose. Stipules broadly lanceolate, connate, persistent, 4-7 mm long, 3.5-4.5 mm wide. Petiolules 1-2 mm long, pilose. Leaflet 1, thin-coriaceous, ovate-lanceolate to subcordate, apex acute or obtuse, mucronate, base cordate to rounded, with 3-5 prominent nerves, 2.5-6.5 (-9.0) cm long, 1.3-3.7 (-5.0) cm wide, glabrous to albo- or rufo-pilose on both surfaces. Inflorescences 2.5-15.5 cm long, usually exceeding the leaflets, multiflorate (8-15), peduncles 1.5-9.5 cm long, pedicels 3-7 mm long. Bracts lanceolate, caducous, 4.0-4.5 mm long, 1.0-1.5 mm wide. Calyx externally glandular, 6.5-7.0 mm long, tube 2.5-3.0 mm long, lobes 3-4 mm long. Corolla yellow, extremely variable in size, 7-13 mm long. Standard broadly obovate, 10-13 mm long, 9.0-10.5 mm wide, auricles 1 mm long, claw 1.5-2.0 mm long. Wings oblong, 6.0-7.5 mm long, 2.0-3.5 mm wide, claw 3.0-3.5 mm long. Keel blades 10.0-12.5 mm long, 4-5 mm wide at maximum, claw 3.0-3.5 mm long. Stamens 12.0-13.5 mm long. Fruit elliptic, albo- or rufo-pilose, 12-13 mm long, 6.0-7.5 mm wide. Seeds brown to black, oblong, 3-4 mm long, 2.0-2.5 mm wide.

Distribution and Ecology - Distribution. Central and southeastern Brazil (Fig. 9). Occurring in pastures, campos-cerrados, on slopes, and along gallery margins at elevations of 600-1000 m.

Discussion

Eriosema heterophyllum var parviflora Benth., Mart. Fl. Bras. 15(1): 210. 1859. Lectotype examined (K): Brazil, Minas Gerais, "Caxoeiras do Campos." P. Claussen & B. Delessert 132. 1839.

Eriosema cordifolium Glaz., nomen nudum, Bull. Soc. Bot. France 35(Mem. 3b): 143. 1906. Brazil, Goias, "Bella Vista, dans le campo." Glaziou 20901. W/o date Isotypes (G, K, S).

Eriosema intermedium Malme, Ark. Bot. 23A(13): 93. 1931. Holotype examined (S): Brazil, Mato Grosso, "Santa Anna da Chapada, in campo paullo ante igni vexato." Malme 11-2253. 13 Aug 1902.

Lectotype examined (K): Brazil, Minas Gerais, "Ad Caldas." Regnell 1-63. W/o date.

Eriosema heterophyllum exhibits some variation throughout its range in southeastern Brazil, but this is mostly in the amount and coloration of the pubescence and the size of the flowers. There seems to be no discernible pattern between these characters and a particular region; for this reason, E . heterophyllum var parviflora of Bentham does not emerge as a distinct entity. E . heterophyllum has often been confused with E. simplicifolium var simplicifolium, but it can be usually distinguished by its broader, more definitely cordate leaflets and longer peduncles with more numerous flowers. As indicated in the key, the racemes of E. heterophyllum usually exceed the leaflets, whereas they are shorter than the leaflets in the typical variety of E. simplicifolium. The latter taxon also has a more extensive distribution. M a l m e described E. intermedium as a hybrid species between E. heterophyllum and E. stipulare on the basis of some shriveled pollen and its occurrence among the supposed parents. Examination of the type specimen shows some possible evidence of introgression but, considering Malme's own qualifying statement that the plant is "probably a hybrid species," as well as its scarcity at the collection site, the population is evidently not self-perpetuating. Without detailed biological studies, the meager evidence presented for hybridization seems inadequate. Furthermore, inasmuch as the type of E. intermedium shows it to fall within the normal range of variability exhibited by E. heterophyllum, it is tentatively being made conspecific with the latter taxon pending further investigation.