Paepalanthus sphaeroides Trovó, Echtern. & Sano, 2012

Echternacht, L. & Sano, P. T., 2012, Paepalanthus sphaeroides, a new species of Eriocaulaceae from the Atlantic Forest, Brazil, Blumea 57 (2), pp. 105-108 : 105-108

Paepalanthus sphaeroides Trovó, Echtern. & Sano , sp. nov. — Fig. 1 , 2 ; Map 1

Differt a Paepalantho aequalis vaginae ad pedunculis fortiter constrictae; bractae involucrantes interiores patentis, exteriori superantes; sepalae flores masculinis ad media parte conatae. — Typus: M. L. O. Trovó 319, M. Mitne, G. Müller, L. M. Borges (holo SPF; iso B, NY, SP), Brazil, São Paulo, Piquete, “trilha para o Pico dos Marins, pouco após a Pedra do Careca ”, 16 Dec. 2006 .

Etymology. The epithet sphaeroides refers to the general habit of the flowering individuals, resembling a sphere.

Perennial herbs. Stem short, 2 – 5 cm long. Leaves arranged in rosette, flats, linear to lanceolate, chartaceous, (5–)12– 21.5 by (0.3 –) 0.5–1 cm long, green with cream base, glabrous on both surfaces, margin ciliate to glabrescent, apex acute. Sheaths tightly adpressed to scapes, membranaceous, 2 – 3.5 cm long, glabrous, apex truncate. Scapes free, 10– 50 per plant, arranged in groups of 3– 5 on a single plane on the axil of consecutive leaves, (5–) 12– 23 cm long, multicostate, glabrous. Capitula 0.6–1.2 cm diam, white. Involucral bracts in 3 –5 series, oblong, c. 6 mm long, paleaceous, pilose to glabrescent on abaxial surface, ciliate toward the acute to mucronate apex. Flowers 3-merous, c. 57 per capitula: 5 × more staminates than pistillates. Floral bracts obovate, c. 3 mm long, pilose on abaxial surface, ciliate toward the acute apex. Staminate flowers c. 4 mm long; pedicel c. 1 mm long, with long trichomes; sepals fused from the base to the middle, obovate, c. 3 mm long, pilose on abaxial surface, ciliate toward the acute apex; corolla tubular, membranaceous, hyaline; stamens c. 2 mm long, anthers castaneous; pistillodes 3, papillose. Pistillate flowers c. 5 mm long, pedicel c. 1 mm long, with long trichomes; sepals fused at base, obovate, c. 4 mm long, castaneous, pilose on abaxial surface, ciliate toward the obtuse apex; petals membranaceous, obovate, c. 4 mm long, hyaline pilose on abaxial surface, ciliate toward the acute apex; gynoecium c. 4 mm long, stigmatic branches bifid at the apex, 2 × longer than the nectariferous branches; staminodes 3, scale-like. Fruit a loculicidal capsule.

Distribution — Paepalanthus sphaeroides occurs on the Mantiqueira Range. There are collections from the munici- palities of Piquete (SP) and Alagoa (MG) on the border of São Paulo and Minas Gerais states. These localities are around 80 km from each other, and probably the species also occurs between both regions, which is a poorly sampled area. Populations were found growing on altitudes between 1900 – 2350 m by the tracksides to Pico dos Marins (Piquete) and to Pico do Garrafão (Alagoa).

Habitat & Ecology — The species occurs in Campos de Altitude, growing over oligotrophic sandy to argillaceous soils ( Benites et al. 2003). Populations of about 20– 50 perennial individuals were found in full anthesis between November and December. Fully developed fruits were found in December and July. The seeming gap in the fructification period is probably due to lack of fieldwork, and the flowering and fructification period may be correlated with the beginning of the rainy season. The seeds are usually ejected jointly with the fruits by the reflexing calyx, as previously described for other species of Paepalanthus ( Stützel 1984, Hensold 1988).

Additional specimens examined. M. F. Santos 04 , A. B. Junqueira, D. Sassaki , L. G. Temponi , L.M. Bezerra ( NY, SPF), Brazil, São Paulo, Piquete, July 2004 ; L. Echternacht 1564 , P. L. Vianna , N.F. O. Motta ( BHCB, SPF), Brazil, Minas Gerais, Alagoa, Parque Estadual do Pico do Papagaio , W44°46'10", S22°12'15", 2397 m alt., 10 Nov. 2007 ; L. Echternacht 1568 , P. L. Vianna , N.F. O. Motta ( BHCB, SPF), Brazil, Minas Gerais, Alagoa, Parque Estadual do Pico do Papagaio , W44°44'58", 22°12'46", 2002 m alt., 10 Nov. 2007 .

Conservation status — The species is known from two populations occurring on the tracksides to mountain peaks, one of them occurring within a conservation unit (Papagaio State Park in Minas Gerais). Further populations may be found in the nearby vicinity, as this is a relatively large and unexplored area. Through the available data, the species is considered endangered according to IUCN (2001) by the following criteria: B1, B2a i, and B2a iv.

Notes — Paepalanthus sphaeroides is placed in Paepalanthus ser. Paepalanthus , as it possesses leaves in rosette, axillary escapes, and trimerous flowers. From the remaining species of this category, P. sphaeroides is distinguished by its membranaceous sheaths tightly adpressed to the scapes, patent involucral bracts slightly surpassing the capitula, and sepals of the staminate flowers fused from the base to the middle. The scapes are not solitary, but grouped on a single plane on the axil of subsequent leaves. This inflorescence arrange- ment was previously reported for Paepalanthus eriophaeus Ruhland and Paepalanthus polygonus Körn. ( Stützel 1984) . The former species shares further morphological similarities with P. sphaeroides . Both are placed within Paepalanthus ser. Paepalanthus , have linear to lanceolate ciliated leaves with approximately the same size of the scapes, and membranaceous sheaths with truncated apex. However, in addition to the features cited above, P. sphaeroides is also distinguished from P. eriophaeus by its leaves with acute apex (vs mucronate), larger size of the leaves (12– 21.5 vs 7–11 cm), tightly adpressed sheaths (vs lax), and paleaceous involucral bract (vs light brown). Both species are allopatric distributed, as P. eriophaeus is restricted to the Diamantina Plateau in the vicinity of Diamantina (MG) .

Throughout the Mantiqueira Range and adjacencies, a com- plex of possible related species comprising P. aequalis (Vell.) J.F.Macbr. , P. cachambuensis Silveira , P. henriquei Ruhland , P. mendoncianus Ruhland , and P. michaelli Silveira share morphological similarities with P. sphaeroides . These species have linear to lanceolate leaves of approximately the same size of the scapes. From this bulk of species, P. sphaeroides is morphologically most related to P. aequalis , showing about the same size and being both sympatric, as they occur in meadows of the Mantiqueira Range. Nevertheless, P. sphaeroides is easily recognized by the grouped scapes (vs solitary), paleaceous bracts (vs dark-brown), and wider capitula (0.6–1.2 vs 0.3 –0.5 cm). Despite the possibility of a sympatric distribution, populations of both species were not found at the same localities.

Figures

Map 1 Distribution of Paepalanthus sphaeroides Trovó, Echtern

Fig. 1 Paepalanthus sphaeroides Trovó, Echtern. & Sano. a. Habit; b. capitula. — Scale bars: a = 4 cm; b = 0.5 cm (Trovó et al. 319).

Fig. 2 Paepalanthus sphaeroides Trovó, Echter. & Sano. a. Habit; b. capitula detail; c. sheath detail; d. involucral bract abaxial surface; e. floral bract abaxial surface; f. pistillate flower; g. gynoecium; h. staminate flower with sepals opened; i. staminate flower with sepals removed (Trovó et al. 319, SPF).