Borreria psyllocarpoides E. L. Cabral & L. M. Miguel 2015, sp. nov.
Creators: name: Miguel, Laila M.
name: Souza, Elnatan B.
name: Cabral, Elsa L.
Publisher: name: Zenodo
Year: 2015
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Magnoliopsida
Gentianales
Rubiaceae
Borreria
Borreria psyllocarpoides

description: Borreria psyllocarpoides E. L. Cabral & L. M. Miguel, sp. nov.
Type:— BRAZIL. Goiás: Canal de São Simão, 18 September 1972, A. P. Duarte 14082 (holotype RB!, isotypes CTES!, NY, US) (Figs. 2, 3 D–G, 4 C–D).
Borreria psyllocarpoides is similar to B. tenuis Candolle (1830: 543), but differs from that species by the white corolla, glabrous throughout (vs. corolla lilac to pale blue, externally papillose and internally with a fringe of moniliform hairs on the tube and tufts of papillae on the lobes), stamens and style exerted (vs. stamens and style included), pollen grains pantoporate (vs. pollen grains colporate), seeds subellipsoid, 1.5–1.7 mm long, concave ventral face with a wide longitudinal groove with the margin transversally furrowed, seed coat papillate (vs. seeds obovoid, 0.8–1 mm long, flat ventral face with a longitudinal groove with entire margin, seed coat reticulate-foveate).
Erect subshrubs, 36–46 cm tall, distal branches pseudodichotomous; stems quadrangular to terete, glabrous, internodes 0.5–2.5 cm long. Leaves opposite, pseudoverticillate, with axillary brachyblast, sessile; blades linear, 10–22 × 0.2–0.5 mm, glabrous, margins revolute. Stipular sheath 1.8–2 mm long, glabrous, edge truncate with 3–5 bristles; bristles 1–2 mm long, glabrous. Glomerules terminal, pauciflorous, 2–5 mm wide; involucral bracts 2, linear, 4–8 × 0.2–0.5 mm, 2 times longer than the glomerule. Flowers subsessile, pedicels 0.3–0.5 mm long; hypanthium 1–1.2 mm long, glabrous; calyx 4–lobed, lobes narrowly triangular, 1–1.3 mm long, glabrous, margin scaberullous; corolla 4–lobed, infundibuliform, 3.5–3.7 mm long, white, glabrous throughout; stamens exerted, filaments 1.8–2.2 mm long, anthers 1 mm long; style 3 mm long, stigma slightly 2–lobed, ca. 0.2 mm wide; nectariferous disc bipartite. Capsules obovoid, 3–3.3 × 2–2.3 mm, glabrous. Seeds subellipsoid, 1.7 × 1 mm, brown, ventral side with a wide longitudinal groove, strophiole is not visible in SEM images (probably caducous), seed margin transversally furrowed on ventral side; seed coat papillate, the exotesta cells are isodiametric, with round radial walls, microsurface of the exotesta cells is smooth in dorsal side and rugose in marginal furrow on the ventral side.
Pollen morphology: —The pollen grains of B. psyllocarpoides are spheroidal, 11–12 pantoporate, and 24 (25) 29 μm in diam., in polar view the outline is circular. The exine is 3 μm thick, the ectopore is 1μm in diam., the operculum is present; the endoaperture is an indistinct endopore. The tectum is perforate and microspines are uniformly present. (Fig. 4 C–D)
Distribution and Habitat: — Borreria psyllocarpoides occurs in Brazil, in the states of Goiás and Minas Gerais, along the margins of the river Paranaíba, in the Canal do São Simão. This area is included in the “cerrado” vegetation (Fig. 5).
Conservation status: —In this study we analyzed specimens from Canal do São Simão, a narrow canyon of 600 m wide, formed by the Paranaíba River, and representing the natural limit between the states of Minas Gerais and Goiás. These specimens were collected by Duarte in 1970 and 1972. In 1978, the São Simão Dam began to operate, which meant that the Canal and the original City of São Simão were flooded. Therefore, following the IUCN criteria (IUCN 2012), this species is data deficient (DD) because we consider that information about its current distribution is lacking.
Phenology: —Flowering and fruiting from September to November.
Etymology: —The specific epithet refers to the similarities of this new species with Psyllocarpus schwackei K. Schumann (1898: 18), another member of the tribe Spermacoceae. Both species are similar in the habits, the linear leaves and the pauciflorous glomerules.
Comments: —Studied specimens were formerly identified as Psyllocarpus in different herbaria and probably the most similar species is Psyllocarpus schwackei which also occurs in Minas Gerais state, in the Serra do Espinhaço (Kirkbride, 1979). However, B. psyllocarpoides differs from P. schwackei mainly by the corolla 3.5–3.7 mm long, white, glabrous throughout, the capsule with septicidal dehiscence from the apex and both cocci dehiscent without a persistent septum, while in P. schwackei the corolla is 3.8–6.1 mm long, blue, externally minutely and densely papillate, internally glabrous, and the capsule dehiscent from the apex downwards along the edge of the septum which is persistent, entire and erect, and both cocci are free.
Representative Specimen Examined (paratype): — BRAZIL. Minas Gerais: Margem do Paranaíba, Canal de São Simão, 2 November 1970, A. P. Duarte 13908 (F, HB).
description: Published as part of Miguel, Laila M., Souza, Elnatan B. & Cabral, Elsa L., 2015, Two new species of Borreria (Spermacoceae, Rubiaceae) from the states of Goiás and Minas Gerais, Brazil, pp. 149-157 in Phytotaxa 201 (2) on pages 153-155, DOI: 10.11646/phytotaxa.201.2.5, http://zenodo.org/record/13641405