Curarea crassa Barneby

Ortiz, Rosa del C., 2018, A taxonomic revision of Curarea Barneby & Krukoff (Menispermaceae), PhytoKeys 100, pp. 9-89 : 30-33

3. Curarea crassa Barneby Figs 15 , 16

Curarea crassa Barneby, Brittonia 48: 20. 1996. Type: Brazil. Bahia: Uruçuca, 14°25'S; 39°01'W [39°03'W], 2 Dec 1994 (old fr), Jardim et al. 351 (holotype: CEPEC n.v.; isotypes: K!, NY! [image seen].

Description.

Large canopy lianas ca. 24 m tall; older stems with the lower part strongly flattened (width unknown); bark greyish to dark brown; branchlets dense and coarsely golden to silvery villose. Leaves: blades 8-10 × 6-9 cm, broadly elliptic to suborbicular, (narrowly ovate), coriaceous when mature or when directly exposed to sunlight in the canopy; surfaces discolorous, lustrous and glabrous adaxially, but sometimes sparsely tomentellous on main veins, golden or cream villous abaxially, the indumentum concealing the epidermis at all stages, base truncate to widely obtuse, margin entire, apex acuminate (especially when juvenile or not directly exposed to sunlight) to acute or retuse when mature or exposed to direct sunlight up in the canopy, 5-7 palmati- or plinerved, innermost pair of main veins acrodromous perfect on mature leaves, acrodromous imperfect on juvenile ones, secondary veins 0-2 pairs, arising almost at the apex of the blade, all veins slightly immersed adaxially, raised abaxially, but concealed by the indumentum; petioles 2.7-4.5 cm long, ridged, sparsely to densely golden or silvery villous, apical pulvinus conspicuous, rugulose, slightly flat to shallowly grooved or rounded adaxially. Staminate inflorescences solitary or fascicled, axillary or supra-axillary, thyrsi (Fig. 15A-B ), golden villous tomentose; axes 9.8 cm long; primary branches compact and up to 1.1 cm long, with reduced (0-1) branching orders; bracts ca. 0.8 mm long, ovate, concave, fleshy, glabrous adaxially, golden villose abaxially.

Pistillate inflorescences (old) solitary or fascicled, axillary, few-flowered thyrsi, indumentum as on staminate inflorescences; axes ca. 3.8 cm long; bracts not seen, primary branches 0.6 cm long, indumentum as on the axis. Staminate flowers ca. 1.4 mm long, pale cream; pedicels ca. 1.3 mm long, terete, indumentum as on the axis; bracteoles 2, ca. 0.5 × 0.3 mm, narrowly ovate, fleshy, glabrous adaxially, light golden tomentose abaxially; sepals 6, indumentum as on bracteoles; outer sepals ca. 0.8 × 0.5 mm, ovate-lanceolate to ovate, base truncate, apex acute to obtuse; inner sepals ca. 1.4 × 1.3 mm, obovate or rhombic, base and apex obtuse, tip of inner sepals erect to hardly inflexed past anthesis; petals 6, ca. 0.7-0.8 × 0.6 mm, obovate, weakly concave, membranous, glabrous adaxially and abaxially, base cuneate, lateral margins inflexed, partially clasping the filaments, apex truncate or weakly retuse; stamens 6; filaments ca. 0.5 mm long, clavate, thick, free, glabrous adaxially and abaxially; anthers ca. 0.3 mm long, erect, connective thicker adaxially and forming a protruding keel at the base of the anthers (Fig. 15H ), not overgrowing the thecae when older. Pistillate flowers ca. 2.1 mm long, greenish; pedicels ca. 0.5 mm long, appearing ridged, indumentum as on staminate inflorescences; bracteoles 2, 0.7 × 0.4 mm, ovate-lanceolate, fleshy, glabrous adaxially, light golden tomentose abaxially; sepals 9, in three whorls, glabrous adaxially, light golden tomentose abaxially; outer sepals ca. 0.9 × 0.5 mm, ovate-lanceolate; middle sepals ca. 1.6 × 0.7 mm, lanceolate to ovate-lanceolate; inner sepals 2.1 × 1.2 mm, elliptic or rhombic, their tips erect or weakly reflexed past anthesis; petals 3, ca. 1.3 × 1 mm, spatulate, weakly concave, membranous, glabrous adaxially, sparsely to densely silvery tomentellous abaxially, base clawed, apex truncate to slightly retuse; carpels 3, 1.1 × 0.7 mm, villous; style 0.4 mm long. Infructescences axes ca. 0.5-1.2 × 0.4-0.6 cm, indumentum moderate greyish-silvery tomentose; fruiting pedicels 5.8-6.1 mm long, terete; carpophores subglobose, ca. 2.4 mm long, convex at apex, golden villous. Drupelets 3.5 × 2.9 cm, (colour when ripe unknown), broadly obovoid (Fig. 16A ), centrically or only weakly eccentrically attached, base oblique, stylar scar inconspicuous, surface golden villous; exocarp 6.7 mm thick, outer surface rugose, granular when dried; mesocarp not seen, but likely thin and mucilaginous; endocarp ca. 2.6 × 2.2 cm, papyraceous to chartaceous, surface smooth. Seeds and embryo not seen, (horny, ca. 23 × 18 mm, Barneby 1996).

Distribution and ecology.

Curarea crassa is known only from the coastal Atlantic Forest of Bahia in Brazil (Fig. 9 ), at ca. 76 m in elevation. Staminate flowering specimens were collected in May, whereas a pistillate flowering specimen was collected in February and immature fruiting specimens were collected in July and December.

Common names and uses.

Brazil: “buta” ( Fróes 12701/67, st).

Etymology.

Not explained in protologue, but likely the name is in reference to its thick exocarp (mesocarp in original description).

Conservation status.

The five collections representing three localities resulted in an estimated EOO of 45 km2 and an AOO of 12 km2. The three localities correspond to two subpopulations and two locations, of which one is found within a protected area.

However, ongoing deforestation in the largely degraded Brazilian Atlantic forest may negatively affect the already localised subpopulations of C. crassa , further reducing suitable habitat. Based on these considerations, C. crassa is here assigned a preliminary status of “Endangered” [EN B1ab(i,ii,ii,iv,v) + B2ab(i,ii,ii,iv,v)].

Discussion.

Curarea crassa is vegetatively conspicuous because of its broadly elliptic or suborbicular leaves covered with a dense golden or creamy villous indumentum on the abaxial leaf blade surface. Similar indumentum may sometimes also be observed on the abaxial leaf blade surfaces of C. barnebyana and C. tecunarum ; from C. barnebyana , it differs by its woolly, greyish-golden indumentum in the staminate inflorescences (vs. dark-brown). From C. tecunarum , C. crassa differs by its primary branches with few branching orders in the staminate inflorescence (vs. primary branches with several branching orders in C. tecunarum ). Also, the large and broadly obovoid drupelets are unique to C. crassa .

The thick layer, from which the specific epithet is likely derived, was described as the mesocarp ( Barneby 1996), however it is likely that the mesocarp in C. crassa , as in C. barnebyana , C. tecunarum and C. aff. iquitana , is mucilaginous and no longer noticeable in dried fruits, as was the case reported for C. tecunarum ( Barneby and Krukoff 1971).

On morphological grounds, C. crassa is placed with the species of Group I. Micro-morphological characters shared amongst species in Group I are summarised in Table 5 . Curarea crassa shares its staminate inflorescences with condensed branch orders with species of that group. They differ in the inflorescence indumentum colour, this being cream or golden in C. crassa vs. dark brown or greyish in C. barnebyana . The primary branches of the staminate inflorescences are also condensed in C. candicans , but there, trichomes are strigillose-tomentellous and not villous as in C. crassa .

In the protologue of C. crassa , Barneby (1996) described staminate flowers as having 9 sepals, but only 6 sepals were found in the only staminate plant available in this study (Thomas et al. 10900). This discrepancy is likely due to infraspecific variation as was also occasionally observed in C. candicans and in C. aff. iquitana .

Specimens examined.

BRAZIL. Bahia: Uruçuca, Serra Grande, 7.3 km na Estrada Serra Grande / Itacaré, Fazenda Lagoa do Conjunto Fazenda Santa Cruz , 14°25'S; 39°01'W [39°03'W], 19 Jul 1994, (♂ fl), Carvalho et al. 4563 (CEPEC n.v., NY! [image seen]; Regiao da Mata Atlantica , 14 Jul 1995, (imm fr), Carvalho et al. 6031 (NY!); Una, Reserva Biologica do Mico-Leao (IBAMA), entrada no km 46 da rod, BA-001, Ilhéus /Una, Regiao da Mata Higrofila Sul Bahiana , 8-10 km na Estrada que margeia ao Rio Maruim , 15°09'S; 39°05W, 6 Jun 1996, (imm fr), Carvalho et al. 6222 (CEPEC n.v., NY! [image seen]); Ilhéus, basin of Rio Santa Ana , high forest, near Bom Gosto, 8 Dec 1942 (st), Fróes 12701/67 (A!, NY n.v.); Uruçuca, Serra Grande, 7.3 km na estrada Serra Grande/ Itacaré, Fazenda Lagoa do Conjunto Fazenda Santa Cruz , 14°25'S; 39°01'W [39°03'W], 9 Feb 1995, (♀ fl), Jardim et al. 609 (NY!); 7.4 km north of Serra Grande on road to Itacaré, 14°25'24"S; 039°03'38"W, 12 May 1995, (♂ fl), Thomas et al. 10900 (MO!, NY!) .

Figures

Figure 9. Geographic distribution of Curarea barnebyana, C. candicans, C. crassa, C. cuatrecasasii and C. gentryana.

Figure 15. Curarea crassa staminate plant: A flowering branch B detail of inflorescence C flower bud D inner sepal, adaxial surface E-F outer and inner petals, abaxial views G-H outer stamens, abaxial-lateral surfaces (based on Thomas et al. 10900).

Figure 16. Curarea crassa pistillate plant: A fruiting branch B innermost sepal, adaxial surface C petal, abaxial surface D carpels (based on Jardim et al. 609).