Siderasis almeidae M.Pell. & Faden, 2017

Pellegrini, Marco O. O. & Faden, Robert B., 2017, Recircumscription and taxonomic revision of Siderasis, with comments on the systematics of subtribe Dichorisandrinae (Commelinaceae), PhytoKeys 83, pp. 1-41 : 15-18

2. Siderasis almeidae M.Pell. & Faden sp. nov. Figs 2 , 7

Diagnosis.

Similar to S. fuscata due to its rusty indumentum in the leaves, lilac to purple rhomboid petals and white anthers. Also, similar to S. albofasciata due to its sessile to subpetiolate leaves, blades adaxially hispid and abaxially lanate, present bracteoles, and purple filaments and style. Nevertheless, Siderasis almeidae is peculiar in lacking terminal tubers in the roots, subterraneous stems, and having aerial stems elongate and trailing in the leaf litter, leaves entirely green, fleshy showy sepals, and a densely lanate ovary.

Type.

BRAZIL. Bahia: Itamarajú, Fazenda Pau Brasil, caminho para o Monte Pescoco , fl., 19 Nov 2015, M.O.O. Pellegrini & R.F. Almeida 493 (holotype: RB barcode RB01132619!; isotype: US!).

Description.

Herbs ca. 20-45 cm tall, terrestrial. Roots thin, fibrous, terminal tubers absent. Rhizomes only covered by leaf litter. Subterraneous stems absent. Aerial stems trailing, only covered by leaf litter, unbranched to little branched, produced directly from the short rhizome; internodes elongate, green, sparsely lanate, becoming glabrous at age, hairs light brown to rusty; flagelliform-shoots (ramets) absent. Leaves spirally-alternate, forming a rosette at the apex of the stems, sessile to subpetiolate; sheaths 1.5-3.2 cm long, green, lanate, margin densely lanate, hairs light brown to rusty; subpetiole 0.8-4.6 cm long to inconspicuous, D-shaped in cross section, canaliculate, green, hispid, margin densely lanate, hairs light brown to rusty; blades 12.6-25.7 × 4-9.1 cm, succulent, elliptic or narrowly obovate to obovate, base cuneate, margins green, slightly revolute, densely lanate, apex acute, curved downwards, adaxially green to dark green, hispid, hairs light brown to rusty, abaxially light green, lanate, light brown to hairs rusty; midvein adaxially inconspicuous to conspicuous, slightly impressed, abaxially prominent, obtuse, secondary veins 6-8 pairs, adaxially conspicuous, slightly impressed, abaxially slightly prominent, becoming more evident adaxially when dry. Synflorescence composed of a solitary main florescence, or with 1-3(-5) coflorescences. Main florescence (inflorescence) reduced to a solitary pedunculate cincinnus; basal bract triangular, 2.4-4.6 × 1.1-2.2 cm, slightly cymbiform, amplexicaulous, green, hispid, hairs rusty, opaque at the base and margins; inflorescence main axis 2.2-8.6 mm long, green, densely hispid, hairs rusty; cincinni bract 1.1-3.6 × 0.4-1.4 cm, narrowly triangular, amplexicaulous, green, hispid, hairs rusty, apex acuminate; cincinni 5-11-flowered, peduncles 0.7-1.8 cm long, green, densely hispid, hairs rusty, reflexed in fruit; bracteoles 7.4-15.3 × 3.8-7.4 mm, broadly triangular, sessile, revolute, green at pre-anthesis, becoming purple at anthesis, hispid to densely hispid, hairs rusty, apex acuminate. Flowers bisexual, actinomorphic, 1.6-2.2 cm diameter, sessile; pedicel inconspicuous at anthesis, elongated in fruit, 0.8-2.2 mm long; floral buds 5.7-7.6 × 4.6-6.5 mm, broadly ellipsoid to broadly obovoid, green, apex obtuse to truncate; sepals 6.8-10.9 × 2.3-5.9 mm, ovate to broadly ovate, fleshy, externally green, densely hispid, hairs rusty, internally lilac to purple, glabrous, margins hyaline to hyaline lilac, apex acute; petals 8-18.2 × 6.4-8.1 mm, rhomboid to broadly obtrullate, purple to bluish purple, base cuneate, margin entire, rarely irregularly lacerated, apex obtuse to rounded; stamens equal, filaments 2.4-4.8 mm long, straight, lilac to purple, anthers 0.7-2.3 × 0.7-1.9 mm, anther sacs white, connectives quadrangular, white; ovary 1.8-2.9 × 1.2-2.1 mm, broadly oblongoid, white, densely lanate, hairs hyaline, style 3.6-4.8 mm long, straight, purple; stigma annular-truncate, purple, papillate. Capsules (immature) 5.7-6.8 × 5.9-7.2 mm, subglobose to broadly oblongoid in outline, smooth, green, when mature light brown, hispid, hairs rusty. Seeds unknown.

Specimens seen (paratypes). BRAZIL. Bahia: Itamarajú, ca. 2 km da Estrada BR-101 ao S de Itamarajú, fl., 5 Apr 1971, T.S. Santos 1559 (CEPEC, K); Fazenda Pau Brasil, ca. 5 km ao NW de Itamarajú, 17°1' S 39°33' W, fl., fr., 19 Sep 1978, S.A. Mori et al. 10730 (CEPEC, K, NY, RB, US); fl., 31 Oct 1979, L.A. Mattos Silva & H.S. Brito 692 (CEPEC, K, US). Prado, rod. BA-001, a 61 km ao N de Alcobaça, fl., 19 Mar 1978, S.A. Mori et al. 9739 (CEPEC, RB); km 21 of road from Itamarajú to Prado, forest on N side near logging operation, fl., 9 Feb 1993, J.A. Kallunki & J.R. Pirani 474 (NY, SPF).

Etymology.

The epithet honors Brazilian botanist Rafael Felipe de Almeida, a prominent specialist in Malpighiaceae , contributor in the studies of Commelinaceae , husband of the first author, and co-collector of the holotype, for his unmeasurable support in the field and in my research.

Distribution and habitat.

Siderasis almeidae is confined to the municipalities of Itamarajú and Prado, Bahia (Fig. 2 ). It occurs in the "mata higrófila” vegetation with emerging rocky formations, in shady and moist areas. In the type locality, the subpopulations were found growing in great accumulations of leaf litter, among dense clusters of Marantaceae . The area is greatly disturbed, and within private property.

Phenology.

It was found in bloom from September to April, beginning to fruit in September, but mature fruits are unknown.

Conservation status.

Siderasis almeidae has considerably narrow EOO (ca. 180.390 km2) and AOO (ca. 2800 km2). Most of the known collections were made in the type locality, in a small forest patch inside a private cattle farm. None of the known subpopulations is protected by a conservation unit, and the southern region of Bahia has few undisturbed areas of Atlantic Forest, being subjected to ongoing deforestation, cattle breeding, and several crops. The subpopulations of S. almeidae are small to medium-sized (with ca. 20 individuals), but mainly composed of clonal individuals. Thus, following the IUCN (2001) criteria, we suggest S. almeidae to be considered Critically Endangered [CR, A2abcd+B2ab(i, ii, iii, iv, v)+C1].

Affinities.

Siderasis almeidae is similar to S. fuscata due to their rusty indumentum covering the leaf blades, inflorescences and sepals, lilac to purple petals, and white anthers. It is also similar to S. albofasciata due to its sessile to subpetiolate leaves, present bracteoles, and purple filaments and style. Furthermore, S. almeidae is similar to S. medusoides , due to their sessile flowers, purple filaments and style, and white anthers.

Figures

Figure 2. Distribution map of Siderasis Raf. emend. M. Pell. & Faden. Blue circles - S. albofasciata; Blue triangles - S. almeidae; Red circles - S. fuscata; Red triangles - S. medusoides; Blue square - S. spectabilis; Red Square - S. zorzanellii; BA - state of Bahia; ES - estate of Espirito Santo; RJ - estate of Rio de Janeiro.

Figure 7. Siderasis almeidae M. Pell. & Faden. A habit, showing a fertile rosette B detail of the elongated aerial stem, showing the rusty internodes and leaf-sheaths C detail of the lanate indumentum on the abaxial side of the leaf blade D detail of the hispid indumentum on the adaxial side of the leaf blade E detail of the inflorescence, showing the contracted cincinnus and some floral buds F front view of a flower, showing the fleshy and internally purple sepals, and the lanate ovary. Photographs A, F by M. A. N. Coelho, remaining photographs by M. O. O. Pellegrini.