Phyllanthus chapadensis P. Orlandini and M. J. Silva

Orlandini, Priscila, Cordeiro, Inês, Silva, Marcos José Da & Souza, Vinicius Castro, 2022, Phyllanthus chapadensis, a new phyllocladiferous Phyllanthus (Phyllanthaceae) from the Chapada dos Veadeiros, Goiás, Brazil, Phytotaxa 532 (2), pp. 169-175 : 170-173

Phyllanthus chapadensis P. Orlandini and M. J. Silva , sp nov. ( Fig. 1 )

Type:— BRAZIL. Goiás. Teresina de Goiás: Rodovia GO 118, 23km ao Norte de Alto Paraíso , 1400 m. a.s.l., 26 March 1982, fl., A.C. Allem 2844 (holotype CEN!; isotype SP!) .

Diagnosis:— Phyllanthus chapadensis is similar to P. sarothamnoides and P. spartioides , having in common the general erect shrubby habit, with fine and delicate phylloclades. However, it can be differentiated from P. sarothamnoides in that it has cylindrical phylloclades, filaments fused with free anthers, and curved, deeply bifid stigmas (vs. flattened phylloclades, especially in the terminal portion, stamens completely fused and multifid stigmas in P. sarothmnoides ). It can be differentiated from P. spartioides by presenting completely cylindrical phylloclades and stamens with free anthers (vs. phylloclades flattened in the terminal portions and stamens with fused anthers in P. spartioides ).

Description— Subshrubs or shrubs, 0.6–1.5 m tall, sympodial growth, densely ramified, phyllanthoid branching, pinatiform or, often, bipinatiform, starting at about 1 third of the stem height up to half of the main branch that is cylindrical woody, secondary branches transformed into cylindrical phylloclades, glabrous, straight and ascending, spirally arranged, semi-succulents, light green, apex truncated, or obtuse, base attenuate, 3–18 × ca. 0.1 cm, striated with linear, not prominent, fine streaks not converging into pairs for the margins, inflorescences emerging from the axils of small nodes, being 9–19 nodes per phylloclade, internodes 0.9–1.5 cm long. Cataphylls and eophylls not seen. Stipules 0.1–0.2 × 0.2–0.3cm, triangular, acuminated apex, straight base, entire margin slightly lacerated, persistent. Persistent leaves, 1–2 × ca. 2 mm usually associated with inflorescences, fleshy, elliptical, ericoid, brochidodromous, with barely noticeable ribs, glabrous, acuminate shortly mucronulate, margin entire, sessile or with petiolate, petiole up to 1 mm long, cylindrical, greenish. Unisexual inflorescences. Staminate cymules with (1–)2 flowers; subtended by bracts 0.1–0.3 × 0.2–0.3 mm, narrowly triangular glabrous, non-congested, membranaceous, entire or lacerate at the margin. Pistillate cymules consisting of solitary flowers; bracts 1–0.3 × 0.2–0.3 mm, membranaceous, narrowly triangular, glabrous, entire margin or lacerated. Staminate flowers 2.1–3.2 mm long, pedicel 2–3 mm long; tepals 6, 0.1–0.2 × ca. 0.2 cm, oval or elliptical in a single whorl, membranaceous, cream, white, greenish or reddish, all the same size, margin entire, apex rounded or acute; disk extrastaminal with 6 segments oval joined to the base of each tepal; stamens 3, filaments connate into a column 1–2 mm long, anthers up to 0.5 mm long, not fused by the connective, vertical or obliquely dehiscent. Pistillate flowers 7–13 mm long, pedicels 5–10 mm long; tepals 6, 2–3 × 1–2 mm, oval in a single whorl, membranaceous similar to the staminate ones, apex rounded, margin entire; disk annular with an undulate margin; styles 3, fused, deeply bifid, the internal stigmatic portion along the styles divergent, curved; ovary 0.8–0.9 mm long, globose, glabrous, slightly trigonous. Capsule 3–5 × 3–6 mm, triangular in upper view or oval, subglobose, smooth mericarps, greenish, smooth, tepals and stigmas persistent in the ripe fruit; carpophore persistent; Seeds 1.9–2.2 × 1.35–1.5 mm, trigonous, smooth.

Additional specimens examined (paratypes): — BRAZIL. Goiás. Alto Paraíso de Goiás, 14°00’S, 47°30’W, 1525 m. a.s.l., 22 November 1984 fl., A.C. Allem et al. 3103 (CEN, SP); ibd., 14°00’S, 47°30’W, 1525 m. a.s.l., 22 November 1984 fl., fr., A.C. Allem et al. 3104 (CEN); ibd., 25 km a Nordeste de Alto Paraíso (GO-118), 14°00’S, 47°30’W, 1560 m. a.s.l., 05 March, 1986 fl., A.C. Allem & W.L. Werneck 3476 (CEN); ibd., 23 km a Nordeste da cidade ao longo da rodovia GO-118, rumo a Cavalcante, 14°00’S, 47°30’W, 1560 m. a.s.l., 05 March 1986, fl., fr., A.C. Allem & W. Werneck 3477 (CEN); ibd., Parque Nacional da Chapada dos Veadeiros, trilha que passa atrás do morro da Baleia , 14°03’36”S, 47°38’21”W, 17 August 1995 fl., fr., R.C. Mendonça et al. 2271 (IBGE, RB, SP). Cavalcante, Rodovia GO-118, 13°58’S, 47°27’W, 08 February 1987 fl., J.R. Pirani et al. 1869 (ESA SPF); ibd., Parque Nacional da Chapada dos Veadeiros, 13°56’39”S, 47°29’38”W, 1410 m. a.s.l., 12 November 1996, fl., M. Aparecida da Silva & A.J.V. dos Santos 3221 (DAV, IBGE, SP, UFG); ibd., 23 km em direção à Teresina de Goiás, 13°56’39”S, 47°29’38”W, 1410 m. a.s.l., 12 October 1996, fl., M. Aparecida da Silva & A.J.V. dos Santos 3218 (DAV, IBGE). Teresina de Goiás, Rodovia GO-118, 13°38’S, 47°28’W, 1400 m. a.s.l., 26 March 1982 fl., A.C. Allem et al. 2844 (CEN, SP). ibd., Rodovia GO-118, 13°38’S, 47°28’W, 1400 m. a.s.l., 26 March 1982, fl., fr., A.C. Allem et al. 2843 (CEN, SP); ibd., PARNA Chapada dos Veadeiros, 13°57’25”S, 47°28’19”W, 1513 m. a.s.l., 26 October 2011, fl., fr., D.P. Saraiva et al. 308 (CEN, RB); ibd., 1500 m. a.s.l., 04 February 1990, fl., M.M. Arbo et al. 3568 (CTES, HRCB, MBM); ibd., 1250 m. a.s.l., 23 March 1971, fl., fr., H.S. Irwin et al. 33018 (NY, UB, NY); ibd., 15 km a oeste de Veadeiros, 1000 m. a.s.l., 14 February 1966 fl., fr., H.S. Irwin et al. 12853 (MBM, MO, NY, R, UB) .

Distribution and habitat:— Phyllanthus chapadensis appears to be endemic to the Chapada dos Veadeiros region, which constitutes a mountainous complex in the northern region of Goiás that have vegetation represented by several phytophysiognomies, such as “ matas de galeria ”, “ matas ciliares ”, “ matas secas ”, “ cerradão ”, “ cerrado denso ”, “ cerrado típico ”, “ cerrado ralo ”, “ cerrado rupestre ”, “ campos sujos ”, “ campo limpo ” and “ veredas ” according to Ribeiro & Walter (1998). It was found in “cerrados rupestres” in the Serra do Pouso Alto region, municipality of Alto Paraíso de Goiás and Cavalcante, as well as in Teresina de Goiás, growing on clay soils or between rocks close or not to streams between 1250–1550 meters elevation in populations with more than 50 individuals. The altitudes where Phyllanthus chapadensis grows are similar to those of P. sarothamnoides and P. spartioides , from the Espinhaço Range in Minas Gerais, and Bahia states, respectively. This is expected since almost all Brazilian taxa of the genus with phylloclades have a predilection for mountain areas. The distribution map with the areas of occurrence of the new species can be seen in Figure 2 .

Phenology:—Collected with flowers and fruits in February, March, August, and November.

Preliminary conservation status:— Phyllanthus chapadensis has an EOO of 205,340 km 2 and an AOO of 24,000 km 2, which led us to propose it as Endangered (EN), under criteria B2ab [iv, v]. However, the species grows in areas protected by law, such as Chapada dos Veadeiros National Park in places unsuitable for cultivation and civil construction, which ensures its preservation.

Etymology:—The specific epithet “ chapadensis ” is a reference to the The Chapada dos Veadeiros region, in the Goiás State where the new species was found.

Notes: — Phyllanthus chapadensis can be recognized by the shrubby and subshrubby habit with sympodial growth, the secondary branches modified in cylindrical or subcylindrical light green phylloclades, flowers 6-merous, the staminate ones with 6-segmented disk, the pistillate ones solitary with a long pedicel and annular disk, as well as by the triangular to subglobose capsules and smooth seeds. In herborized collections it has been commonly confused with P. sarothamnoides or P. spartioides , two species that occur in Chapada Diamantina, in Bahia, probably by its habit, delicate aspect, and phyllocladiferous branches.

Considering the cylindrical shape of the phylloclades, there are two other species of Phyllanthus sect. Choretropsis that present non-flattened phylloclades: Phyllanthus choretroides Müller Argoviensis (1863: 52) and Phyllanthus goianensis Santiago (1988: 45) , the latter from the same region of Chapada dos Veadeiros. However, these two species form thickets of up to 30 cm in height, whose phylloclades present monopodial growth with a reduced axis. It is also noteworthy that P. choretroides presents flowers with 5 tepals and 2 stamens with anthers of horizontal dehiscence and P. goianensis presents flowers with 5 tepals, and 3 stamens with horizontal dehiscence anthers (vs. 0.6-1.5 m tall plants, with sympodial growth, flowers with 6 tepals and 3 stamens with vertical dehiscence anthers in P. chapadensis ). However, the characters listed in table 1, are surely enough to recognize Phyllanthus chapadensis as a different species from the previously mentioned. It is important to emphasize that the available material of P. goianensis (species known only from the type collection) does not have pistillate flowers, so only staminate flowers were used in the table 1 for P. goianensis .

Additionally, P. chapadensis presents exclusively cylindrical phylloclades, while P. sarothamnoides and P. spartioides the other two species present flattened phylloclades in the adult phase and in the terminal portions. The anthers of the male flowers are not joined, whereas in P. sarothamnoides and in P. spartioides the three stamens form a column with total the fusion of the anthers. The three species can be considered subdioecious, a term used by Webster (1967) to define some species of Euphorbiaceae that present staminate flowers only after the pistillate flower cycle, which can confuse anyone who collects the plants at just one time of the year, suggesting that they are dioecious plants – This fact was noticed in several collections of P. chapadensis , have been highlighted in the exsiccate labels of A.C. Allem et al. 2843 (CEN, SP), A. C. Allem et al. 3103 (SP, CEN), A.C. Allem et al. 2844 (CEN) and A.C. Allem et al. 3104 (CEN). Also considering the classification into subsections made by Santiago et al. (2006), the new species can be classified in the P. sect. Choretropsis subsect. Choretropsis , based on the cylindrical phylloclades.

Figures

FIGURE 1. Phyllanthus. chapadensis. A. Habit; B. Staminate cymules (detail); C. Staminate flower. D. Stamens and extrastaminal disk with one segment removed. E. Pistillate flower. F. Gynoecium. G. Immature fruit. H. Carpophore. I. Seed on ventral (left) and lateral (right) view. Illustrations by Klei Sousa. A and B: A. C. Allem 2844 (CEN); C–D: Allem et al. 3103 (CEN); E–F: D.P. Saraiva et al. 308 (RB); G–I: M. Aparecida da Silva & A.J. V. dos Santos 3221 (IBGE).

FIGURE 2. Distribution map of Phyllanthus chapadensis, P. choretroides, P. goianensis, P. sarothamnoides and P. spartioides.