Psyllocarpus itakangapyra Sobrado, J.A.M.Carmo & R.M.Salas, 2022

Sobrado, Sandra V., do Carmo, João A. M., Simões, André O. & Salas, Roberto M., 2022, Two new species of Psyllocarpus (Spermacoceae, Rubiaceae) from the state of Minas Gerais, southeastern Brazil, European Journal of Taxonomy 806, pp. 161-176 : 163-165

Psyllocarpus itakangapyra Sobrado, J.A.M.Carmo & R.M.Salas sp. nov.

urn:lsid:ipni.org:names:77296003-1

Figs 1 , 3A–I , 4A–H , 5A–D , 6A–F , 7

Diagnosis

Psyllocarpus itakangapyra sp. nov. is similar to P. laricoides Mart. & Zucc. , but differs by the leaves 1.45–3.4 mm long (vs (4)5–16(21) mm long in P. laricoides ), flowering branches determinate (vs indeterminate), inflorescences in terminal glomerules, rarely with axillary inflorescences in 1-flowered cymes (vs axillary inflorescences in 1-flowered cymes), corolla tube 1.78–2.08 mm long (vs 2.9–6.7 mm long), calyx tube absent to vestigial (vs present), and seeds broadly obovate in outline (vs elliptic to broadly elliptic in outline).

Etymology

The specific epithet refers to the municipality of Itacambira, in the state of Minas Gerais, where the species is found. ʻ Itakangapyra ʼ means ʻstone with a pointed headʼ and derives from the ancient Tupi, an extinct Tupi language that was spoken by the Tupi tribes that inhabited most of the Brazilian coast in the 16 th century.

Material examined

Type

BRAZIL • Minas Gerais, Itacambira, Serra Resplandescente , “no caminho para a torre de Itacambira” [on the way to the Itacambira tower]; 17°04′56″ S, 43°18′20″ W; 1304 m a.s.l.; 28 Oct. 2009; Viana, Cardoso, Hattori & Salas 4415; holotype: BHCB[134173]!; isotype: CTES !.

Paratypes BRAZIL – Minas Gerais • Itacambira, MG 308, km 98; 17°04′58″ S, 43°18′35″ W; 17 Jan. 2015; Carmo & Scatigna 297; CTES!, UEC[207471] ! • Itacambira, MG 308, km 99; 17°04′59″ S, 43°18′35″ W; 17 Jan. 2015; Carmo & Scatigna 298; CTES!, UEC[208470] !.

Description

Subshrubs, 0.4–2 m tall, sympodial. Stems branched, erect, internodes 1.25–8.11 mm long, 1.68–3.11 mm wide at the apex, tetragonal to subtetragonal and scabridous, 0.26–1.6 mm wide at the base, subterete and glabrous, bark peeling from older internodes, foliar scars conspicuous. Stipular sheaths 0.48–0.94(1.29) mm long, scabridous to glabrous, 3–5-fimbriate on each side of the stem, fimbriae 0.17–0.68 mm long, linear to narrowly triangular, colleter tipped, margin scabridous. Leaves opposite, with axillary brachyblasts forming fascicles, leaf blades 1.45–3.4 × 0.2–0.45 mm, slightly reflexed, decussate, apparently fleshy, sessile, linear to terete, apex obtuse, glabrous. Flowering branches determinate, 1–4.72 cm long, unbranched or with 3–5 branches per axis, inflorescences in terminal glomerules, 6–10-flowered, 3.4– 5.93 mm wide, rarely a 2–3-flowered cyme axillary, peduncle 2.07–9.28 mm long, external bracts 2, 1.43–2.24 × 0.18–1 mm, patent, linear to terete, apex obtuse, glabrous. Flowers sessile, homostylous; hypanthium 1.03–1.47 × 0.56–1.29 mm, obconic, glabrous; calyx tube absent to vestigial, 2-lobate, 3–5 fimbriae along the calyx rim between the lobes, 0.12–1.61 mm long, colleter tipped, calyx lobes (0.7)0.91–1.14 × 0.22–0.61 mm, narrowly triangular to linear, spatulate, glabrous; corolla 3–3.58 mm long, infundibuliform, lower half of the tube purple, the upper half and lobes light blue, corolla tube 1.78–2.08 mm long, 0.93–1.6 mm diam., external surface papillate, internal surface with a dense ring of moniliform trichomes from the anthers apex to the lobes base, sparsely pubescent between the anthers, and glabrous on the base, 4-lobate, corolla lobes 0.93–1.51 × 0.66–1.11 mm, subtriangular, external and internal surface papillate, rounded in preanthetic bud, this ca 1.09 mm diam., apex rounded; stamens included, inserted at the middle of the corolla tube, filaments 0.22–0.27 mm long, anthers 0.62–0.93 mm long, orbicules present covering uniformly the inner wall of dehiscent anthers, pollen 5-zonocolpate, circular outline in polar view, small-sized (P = 17–22 µm), prolate-spheroidal to prolate (P/E = 1.13–1.4), long and narrow ectocolpi (10–12 µm long), endocingulum (3)4–5 µm wide, tectum psilate microspinose, tipped microspines 0.2–0.4 µm long, distributed mostly around the ectocolpi, exine 0.8–1.4 µm thick; style included, 0.16–0.26 mm long, stigma 0.19–0.27 mm long, bilobate, lobes inconspicuous; nectariferous disk entire, 0.52–0.79 mm diam., with striate cells. Capsule 3–3.74 × 1.73–2.67 mm, obovate in outline, strongly compressed parallel to the septum, 1–3 acrodromous ribs slightly marked on the dorsal surface, glabrous, calyx lobes persistent, dehiscent from the apex downwards, valves persistent from which the seeds are shed after dehiscence, septum persistent, 2.69–3.65 × 1.54–2.15 mm. Seeds 2, 2.15–2.92 × 1.37–1.9 mm, broadly obovate in outline, strongly compressed, ventral surface covered by diffuse strophiole, 0.68–0.96 × 0.35–0.62 mm, dorsal surface slightly convex, testa subtuberculate, with digitallike cells pressed (37.37–93.87 × 17.98–34.18 µm), radially arranged.

Distribution, habitat, and phenology

Psyllocarpus itakangapyra sp. nov. grows on sandy and rocky soils in the “campo rupestre” vegetation (sensu Silveira et al. 2016), at ca 1300 m a.s.l. Currently it is only known from the municipality of Itacambira, in the micro-region of Grão Mogol, northern Minas Gerais ( Fig. 7 ). However, future botanical expeditions to this region may increase the distributional range of this species. Specimens with flowers and fruits were collected in October and January.

Preliminary conservation status

Psyllocarpus itakangapyra sp. nov. does not occur within the limits of any protected area in Minas Gerais. It presents EOO and AOO equal to 1471 km 2 and 20 km 2 (kml file available as Supp. file 1). Therefore, we believe that this species would be considered endangered (EN B2abiii) in an official IUCN red list assessment, based on its EOO less than 5000 km 2 and AOO less than 500 km 2, occurrence in five locations, and continuing decline inferred on quality of habitat due to the impacts on the “campo rupestre” vegetation, which in this case is associated with the expansion of eucalyptus plantations in the region, as noticed by us during fieldwork.

Figures

Fig. 1. Psyllocarpus itakangapyra Sobrado, J.A.M.Carmo & R.M.Salas sp. nov.; P.L. Viana et al. 4415 (CTES). A. Branch portion. B. Inflorescences at the apex of flowering branches. C. Detail of an inflorescence. D. Stipular sheath. E. Preanthetic flower bud. F. Flower. G. Hypanthium, calyx, style, and stigma. H. Opened corolla. I–M. Fruit. I. Dehiscent capsule, lateral view. J. Septum. K. Valve, seed, and septum, cross section. L. Valve, dorsal view. M. Valve, ventral view. N–O. Seed. N. Dorsal view. O. Ventral view. Illustration: L. Simón.

Fig. 3. Flower micromorphology. A–I. Psyllocarpus itakangapyra Sobrado, J.A.M.Carmo & R.M.Salas sp. nov.; P.L. Viana et al. 4415 (CTES). A. Flower bud. B. Papillate external surface of the corolla. C. Hypanthium, calyx, style, and stigma. D. Detail of style and stigma. E. Opened corolla. F. Papillate internal surface of the corolla lobes. G. Moniliform trichomes at internal surface of the corolla. H. Nectariferous disk, top view. I. Detail of striate nectariferous disk cells and functional stomata. J–R. P. vianae Sobrado, J.A.M.Carmo & R.M.Salas sp. nov.; P.L. Viana et al. 5887 (CTES). J. Flower bud. K. Papillate external surface of the corolla. L. Hypanthium, calyx, style, and stigma. M. Detail of style and stigma. N. Opened corolla. O. Papillate internal surface of the corolla lobes and moniliform trichomes. P. Inner wall of a dehiscent anther, showing the prescence of orbicules. Q. Nectariferous disk, top view. R. Detail of striate nectariferous disk cells. Scale bars: A, C, E, J, L, N 200 µm; B, G, K, R = 20 µm; D, F, M = 50 µm; H, O, Q = 100 µm; I = 10 µm; P = 2 µm.

Fig. 4. Fruit and seed micromorphology. A–H. Psyllocarpus itakangapyra Sobrado, J.A.M.Carmo & R.M.Salas sp. nov.; P.L. Viana et al. 4415 (CTES). A–E. Capsule. A. Dehiscent capsule, lateral view. B. Valve, dorsal view. C. Valve, ventral view. D. Cross section capsule. E. Septum. F–H. Seed. F. Dorsal view. G. Ventral view, with diffuse strophiole. H. Detail of the testa. I–P. P. vianae Sobrado, J.A.M.Carmo & R.M.Salas sp. nov.; P.L. Viana et al. 5887 (CTES). I–M. Capsule. I. Dehiscent capsule, lateral view.J. Valve, dorsal view. K. Valve, ventral view. L. Cross section of the valve, seed, and septum. M. Septum. N–P. Seed. N. Dorsal view. O. Ventral view. P. Detail of the testa. Abbreviations: s = seed; se = septum; v = valve. Scale bars: A–G, I–O = 200 µm; H, P = 20 µm.

Fig. 5. Pollen morphology (SEM). A–D. Psyllocarpus itakangapyra Sobrado, J.A.M.Carmo & R.M.Salas sp. nov.; P.L. Viana et al. 4415 (CTES). A. Polar view. B. Equatorial view. C. Detail of apocolpium. D. Detail of the colpus and spinules. E–H. P. vianae Sobrado, J.A.M.Carmo & R.M.Salas sp. nov.; P.L. Viana et al. 5887 (CTES). E. Polar view. F. Equatorial view. G. Detail of the inner side of a pollen fragment showing the endocingulum (en). H. Detail of the colpus and spinules. Scale bars: A–B, E–G = 2 µm; C–D, H = 1 µm.

Fig. 6. A–F. Psyllocarpus itakangapyra Sobrado, J.A.M.Carmo & R.M.Salas sp. nov. A. Habitat, “campo rupestre” in Itacambira, Minas Gerais. B. Habit. C. Branch portion, showing the leaves. D. Inflorescences at the apex of flowering branches. E. Detail of the flowers. F. Capsules. G–M. P. vianae Sobrado, J.A.M.Carmo & R.M.Salas sp. nov. G. Habitat, “campo rupestre” in Serra do Cabral, Minas Gerais. H. Habit. I. Branch portion, showing the leaves. J. Inflorescences at the apex of flowering branches. K. Detail of preanthetic flower buds. L. Detail of an opened flower. M. Dehiscent capsule. Photos: A, C, G–J = R.M. Salas; B, D–F = J.A.M. Carmo; K–L = P.L. Viana; M = S.V. Sobrado.

Fig. 7. Distribution map of Psyllocarpus itakangapyra Sobrado, J.A.M.Carmo & R.M.Salas sp. nov. and P. vianae Sobrado, J.A.M.Carmo & R.M.Salas sp. nov. in the state of Minas Gerais, Brazil.