Comanthera pignalii Echtern., 2014

Echternacht, Livia, 2014, A critically endangered new species of Comanthera from Bahia, Brazil (Paepalanthoideae, Eriocaulaceae), Phytotaxa 186 (3), pp. 166-173 : 167-171

Comanthera pignalii Echtern. , sp. nov. ( Figs. 1–3 )

Type:— BRAZIL. Bahia: Jacaraci, Areia Branca , ao lado da cidade, 14°50’09”S 42°25’31”W, 905 m elev., 20 April 2014, L . Echternacht , T. V . Bastos , M. S . Freitas & A. P. L . Werlang 2427 (holotype HUFU!, isotypes BHCB!, NY!, P!, SPF!) .

Ab alteris speciebus, lanosis foliis spathisque, spathae lacerato apice, capitulis cum involucri cremeis adpressisque aequantibus flores bracteis, pistillatis floribus cum pilosis petalis, praecipue differt.

Perennial herbs, 15–25 cm tall. Stem aerial, 1–2 cm long, erect, unbranched. Leaves rosulate, erect to recurved, terete to semi-terete, lanceolate, 1–2 cm × 0.8–1.2 mm; both surfaces and the margins lanose, with recurved, malpighiaceous, white trichomes; abaxial surface with a thickened central vein; apex round to obtuse. Spathes 1–2 cm long, lanose as the leaves, apex lacerate, membranaceous. Scapes 2–30 per individual, 15–30 cm long at the flowering stage, erect, usually longer and decumbent after anthesis; densely pilose to lanose, with reclinate, malpighiaceous, white trichomes. Capitula 4–6 mm high × 5–12 mm in diameter, campanulate to radiate; involucral bracts in 7–9 series, appressed, equal to the flowers level, bracts cream, margins hyaline, straw-colored at the very base; external series circular to obovate, apex round, 0.8–1.5 × 0.6–1.3 mm, pubescent to glabrescent on the abaxial surface, glabrous adaxially, bracts progressively longer and less pilose towards the inner series, internal series oblong to oblanceolate, apex round, 3.5–4.5 × 0.5–0.8 mm, glabrous on both surfaces. Flowers 3-merous, 50–150 per capitulum; the staminate flowers maturing before the adjacent pistillate flowers, usually twice the number of pistillate than staminate flowers in mature capitula. Floral bracts absent. Staminate flowers 3.8–5.0 mm long, including the pedicel; pedicel 2.0– 2.8 mm long; sepals slightly smaller than or equaling the petals; sepals fused at the very base, concave, elliptic, 1.3–1.8 mm long, glabrous, membranaceous, hyaline, apex round to obtuse; petals fused at the base, concave, elliptic, 1.5–2.2 mm long, glabrous, membranaceous, hyaline, apex round to obtuse; stamens free, ca. 2–3 mm long, exserted; pistillodes ca. 0.7 mm long, connate in the base, papillose at the apex. Pistillate flowers 3.2–5.2 mm long, including the pedicel; pedicel ca. 0.5 mm long at anthesis, elongating to ca. 2.0 mm during fruit maturation; sepals free, concave, elliptic, 1.0– 1.5 mm long, glabrous, membranaceous, hyaline, apex round to obtuse; petals fused at the middle, free at base and top, narrow-spathulate, 2.5–3.0 mm long, hairy on both surfaces at the middle portion, marcescent and glabrescent at fruiting, ascending trichomes ca. 0.3 mm long, membranaceous, hyaline, apex round; gynoecium 2.5–3.5 mm long, stigmatic branches 1.5–2.5 mm long, nectariferous branches ca. 1 mm long, papillose at apex. Seeds ca. 0.5 mm long, elliptic, rugose.

Distribution and habitat:— Comanthera pignalii is known from a single population in Jacaraci municipality, in the locality of Areia Branca, at the border of the Serra Geral, which is an intermediate mountain range between the septentrional and meridional massifs of the Espinhaço range, in Bahia and Minas Gerais states, respectively. This region is located in a transition zone between the Cerrado and the Caatinga biomes, characterized as humid to subhumid ( C 2wB’3a’; Thornthwaite & Mather 1955, SEI 1999). Jacaraci is poorly explored scientifically and the few botanical studies carried out there have revealed a new Bromeliaceae species ( Leme 2010) in addition to the new Eriocaulaceae species described here. There are other probably new Eriocaulaceae , currently under investigation, not only from Jacaraci municipality but also from surrounding mountains. Botanists should feel encouraged to explore this region, as other new taxa are expected.

Comanthera pignalii occurs in a white-sand environment, over sandy, well-drained soils derived from sandstone formations, amongst a shrubby to herbaceous vegetation. The phytophysiognomy evokes the Restinga, a coastal ecosystem composed by dunes. The white-sand open area is surrounded by dense Caatinga vegetation, shrubby to arborescent, forming a deciduous forest. Only one population was found, limited to this strictly sandy and open area, composed of ca. 100 individuals, in groups of three to four plants, usually separated by 5 to 50 m, occupying a very narrow area.

Etymology:—It is a great pleasure to dedicate this distinct species to Marc Pignal, the French botanist and excellent researcher, in honor of his important contribution to botany, especially in Brazil. M. Pignal has worked intensely on the conservation of the P herbarium and integration of European herbaria. He also works with historical Brazilian collections, especially regarding August de Saint-Hilaire, favoring their inclusion in the Brazilian Virtual Herbarium. Without his curiosity, this new species would remain unknown to science, as he was the first to collect it. He is a true naturalist that inspires us all with his enthusiasm and great devotion to botany.

Phenology:—The population was found with flowers and fruits in April and May. The coexistence of old, mature and young inflorescences in the same individual suggest a continuous bloom, although further observations throughout the year are required to confirm this.

Conservation status:—This species is known from a single population and locality, which is not protected by any Conservation Unit. The area is under great human pressure as there are mining activities of sand extraction nearby (less than 200 m away). In addition, its proximity to the town of Jacaraci imposes threats: the Areia Branca site is used for recreation and urban growth could suppress the native vegetation in the near future. The individuals of Comanthera pignalii grow over the sand and are fragilely fixed to the soil. These tiny white plants are hardly visible, and people frequently walk through them. The propitious habitat for the species occurs only at this sandy spot, as there are no similar environments in the region (see Fig. 2G ), which means that possibly there is no other living population. In the white-sand area, the population is restricted to the borders, where the plants find open, sunny conditions, but are protected by the surrounding shrubby vegetation. The area of occupancy is four km 2 and tends to decrease, as well as the extent of occurrence, the quality of the habitat and the size of the population. According to criteria B 21ab (i, ii, iii, iv) ( IUCN 2014), this species is considered critically endangered ( CR). This evaluation was provided by CNCFlora following the methodology described in Martinelli & Moraes (2013).

Discussion:— Comanthera pignalii is easily recognized by a whitish general look, due to a dense cover of white trichomes, leaves and spathes lanose, spathes lacerate at the apex, cream capitula, with appressed involucral bracts equaling to the flowers, and pilose petals of the pistillate flowers. The uniqueness of this species makes it difficult to determine its closest relatives, but the ones that show its most conspicuous features, i.e. a whitish cover of trichomes and woolly leaves, are C. brasiliana ( Giulietti 1996: 63) L.R. Parra & Giulietti in Parra et al. (2010: 1138) and C. floccosa ( Moldenke 1980: 478) L.R. Parra & Giulietti in Parra et al. (2010: 1144). Another distinct feature of C. pignalii is its evenly cream involucral bracts, a character shared only with C. floccosa and C. kegeliana ( Koernicke 1863: 438) Moldenke (1966: 218) .

Comanthera brasiliana shares with C. pignalii lanose leaves and spathes and pilose involucral bracts, but can be easily distinguished by the form of the capitula, which has involucral bracts pale-brown at the base and middle and cream at the apex (vs. completely cream), that are lax and recurved (vs. appressed). In addition, C. brasiliana has much longer (5–8 vs. 1–2 cm long), flat to canaliculated leaves (vs. terete to semi-terete), an acute spathe apex (vs. lacerate) and glabrous petals of the pistillate flowers (vs. pilose). The species are allopatric, as C. brasiliana is narrowly endemic to Rio Vermelho municipality in Minas Gerais, around 250 km south of C. pignalii , although they do occupy similar habitats.

Comanthera floccosa shares with C. pignalii a similar size, lanose leaves, a lacerate spathe apex, and capitula with appressed involucral bracts. It differs in a number of features, as it is morphologically isolated from all other species of C. subg. Comanthera . It can be easily told apart from C. pignalii by its cespitose rhizome (vs. erect and unbranched aerial stem), which is very woolly, with long hairs completely covering and surpassing the leaves, leaves reduced to a lanceolate form barely reaching 6 mm long (vs. 10–20 mm), greenish scapes that are often glabrescent (vs. greyish and always pilose), glabrous involucral bracts (vs. pilose), glabrous petals of the pistillate flowers (vs. pilose) and unique staminate flowers, with petals fused in the middle and free at base and top, and pistillodes with yellowish appendages at the base, projecting between the petals (vs. petals fused at base and pistillodes without appendices). Both species are allopatric, as C. floccosa is narrowly endemic to Gentio do Ouro municipality and surroundings, in the northwestern Espinhaço Range in Bahia, around 350 km north of C. pignalii .

In spite of the shared cream capitula, Comanthera kegeliana is quite different from C. pignalii , easily distinguished by its smaller size, usually not surpassing 15 cm, rosettes of greenish, pubescent leaves (vs. whitish and lanose) and spathes with acuminate apices (vs. lacerate). This species is the only one of the subgenus occurring in the Amazonian savannas, and is therefore allopatric with C. pignalii .

Additional specimens examined (paratypes):— BRAZIL. Bahia: Jacaraci, Areia Branca , 14°50’2.52”S 42°25’18”W, 929 m elev., 5 May 2011, M . Pignal , R . Reis Jr. & M. R . da Silva Jr. 3983 ( HUESBVC!) .

Figures

FIGURE 1. Comanthera pignalii. A. Habit. B. Scape and spathe, showing the lanose indument. C. Capitulum with flowers in early anthesis. D. External involucral bract. E. Internal involucral bract. F. Staminate flower. G. Staminate flower without pedicel and sepals. H. Pistillate flower. I. Gynoecium. Scale bar: A, 3 cm; B, D–I, 1 mm; C, 3 mm. (Drawn from the holotype by L. Echternacht)

FIGURE 2. Comanthera pignalii.A. Rosette of leaves, spathes and base of scapes, showing their whitish appearence due to the white lanose indument. B. Abaxial view ot the capitulum, with evenly cream involucral bracts. C. Young capitulum. D. Capitulum with the first staminate flowers at anthesis. E. Capitulum with developed fruits and dispersing seeds, which are visible amongst the mascescent pistillate flowers. F. Habit and habitat. G. Areia Branca, the white-sand site where C. pignalii occurs, near the town of Jacaraci, and the Serra Geral at the background. (Photos: L. Echternacht)

FIGURE 3. Map showing the occurrence point of Comanthera pignalii, provided by CNCFlora following the standards described in Martinelli & Moraes (2013).