Peltaea stellata, Fernandes-Júnior, Aluisio J. & Esteves, Gerleni L., 2016

Fernandes-Júnior, Aluisio J. & Esteves, Gerleni L., 2016, Three new species of Peltaea (Malvaceae, Malvoideae) from the cerrado of Brazil, Phytotaxa 255 (1), pp. 75-82 : 81

Peltaea stellata A.J.Fernandes-Jr. & G.L.Esteves, sp. nov. Type:— BRAZIL. Tocantins: Goiatins, Sub-bacia do rio Manuel Alves Grande , 7°46’14’’S, 47°16’23’’W, 14 May 2010 (fl, fr), F.C.A. Oliveira et al. 2000 (holotype SP!, isotype IBGE!) . Figures 1R –B’, 3E–H.

Similar to Peltaea speciosa , but differing by the leaf blades coriaceous (vs. chartaceous) with stellate adpressed trichomes (vs. stellate antrorse trichomes), calyx with simple, glandular and stellate trichomes internally (vs. simple and glandular trichomes), free parts of the stamens distributed in two groups along the staminal tube (vs. one group along the staminal tube), mericarps rostrate (vs. apiculate) with simple, stellate and glandular trichomes on dorsal surface (vs. simple and stellate trichomes), column cylindrical, enlarged at the base (vs. cylindrical at the base and conic at apex), seeds trigonous (vs. reniform) with simple trichomes at one of the hilum extremities (vs. simple and biradiate trichomes sparse for all surface).

Shrubs 0.5–0.7 m tall; branches cylindrical, with stellate trichomes. Stipules 3–4 mm long, subulate; petioles 3–11 mm long; leaf blades 6.1–8.1 × 4.5–5.7 cm, ovate, coriaceous, entire, 7–9-palmativeined, apex acute, base cordate, margin serrate, both surfaces with stellates adpressed trichomes. Flowers chasmogamous, solitary in the axil of leaves and/or in terminal reduced racemes (capituliform) subtended by foliaceous bracts; pedicels 0.8–1.3 cm long; bracts 2.1–4.8 × 1.7–3.6 cm, ovate, adaxial surface with long stellate and simple trichomes, reddish at the basal portion, abaxial surface with stellate trichomes; bracteoles of epicalyx 8–9, spathulate, both surfaces with stellate and simple trichomes, ciliate, pedicels 3–5 mm long, blade 7–14 × 2–3.3 mm, narrowly elliptic to ovate, adaxial surface glabrescent; calyx 11–15 mm long, 25-veined, internally with simple, stellate and glandular trichomes, externally with stellate trichomes; petals 4.1–4.8 × 2.4–2.9 cm, pink with a dark basal spot, obovate; staminal tube 1.6–2 cm long, with glandular trichomes, free parts of the stamens distributed in two groups along the staminal tube; styles erect, with glandular trichomes. Mericarps 5–6 mm long, rostrate, dehiscent, dorsal side slightly nerved, with simple, biradiate, stellate and glandular trichomes; column 1.5–2 mm long, cylindrical, enlarged at the basal portion; seeds 4–4.5 × 2–3 mm, trigonous, with simple trichomes at one extremity of the hilum.

Distribution and habitat: —Endemic to the state of Tocantins, Brazil growing in ironstone outcrops (locally known as ‘canga de ferro’) about 200 m elevation ( Figure 4 ).

Phenology: —The new species was collected in flower in March and May, and in fruit in May.

Etymology: —The epithet refers to the stellate trichomes on inner surface of the calyx.

Conservation Status: —According to IUCN (2014) criteria, Peltaea stellata must be considered Endangered [EN, B2ab (i, ii, iii, iv)] because is known from only two unprotected localities.

Notes and taxonomic affinities: — Peltaea stellata is the only species of the genus with stellate trichomes on inner surface of the calyx ( Fig. 3 E ), whereas other species have only simple and glandular trichomes. In addition, it presents several types of trichomes in its mericarp, as seen in scanning electronic microscopy: simple, biradiate and stellate adpressed, stellate antrorse and glandular ( Fig. 3 F–H ). The indument of seed is also unique among the species of the genus, presenting simple trichomes at one of the hilum extremities ( Fig. 1 A’). This type of tufted indument is known also in the genus Pavonia ( Cavanilles 1786: 132) sect. Lebretonia ( Schrank 1822: 90) Endlicher (1840: 982) , for which most of the species presents two tufted seeds, and in Pavonia angustipetala ( Krapovickas & Cristóbal 1962: 51) has only one extremity tufted, like Peltaea stellata .

As referred in the diagnosis the species is similar to P. speciosa ( Kunth 1821: 281) Standley (1916: 113) , mainly due to the ovate leaf blade, spathulate bracteoles of epicalyx and mericarps with simple, biradiate and stellate trichomes in the dorsal surface. Furthermore, P. stellata is only known in the state of Tocantins in Northern of Brazil, while P. speciosa occurs in Midwest, Southeast, Northeast and Northern, besides Venezuela, Colombia, Suriname and Cuba.

Additional specimen examined (Paratype):— BRAZIL. Tocantins: Santa Maria do Tocantins, 8°45’42’’S, 48°04’14’’W, 29 March 2010 (fl), M.L. Fonseca et al. 6529 ( IBGE) .

Figures

FIGURE 1. A–H. Peltaea brasiliana (based in A.J. Fernandes-Júnior 286). A. Flowering branch; B. Details of branch indument; C) Bracteoles of epicalyx. D) Inner surface of calyx. E) Staminal tube. F) Petal. G) Mericarp. H) Seed. I–Q. Peltaea rupestris (based in L.R. Lima et al. 119). I. Flowering branch. J. Details of branch indument. K. Bracteoles of epicalyx. L. Inner surface of calyx. M. Staminal tube. N. Petal. O. Mericarp. P. Seed. Q. Column. R–B’. Peltaea stellata (based in F.C.A. Oliveira et al. 2000). R. Flowering branch. S. Indument of adaxial leaf surface. T. Indument of abaxial leaf surface. U. Bracteoles of epicalyx, abaxial surface view. V. Bracteoles of epicalyx, adaxial surface view. W. Inner surface of calyx and details of indument. X. Staminal tube. Y. Petal. Z. Mericarp. A’. Seed and indument detail. B’. Column.

FIGURE 3. Scanning electron micrographs of Peltaea species. Peltaea brasiliana (based in A.J. Fernandes-Júnior 286). A. Seeds, outside view, simple and biradiate trichomes. Peltaea rupestris (based in L.R. Lima et al. 119). B. Branch with sparse stellate trichomes and longitudinal line of simple and stellate trichomes. C. Bracteoles of epicalyx: adaxial surface with stellate and glandular trichomes. D. Mericarp, dorsal side, simple and glandular trichomes. Peltaea stellata (based in F.C.A. Oliveira et al. 2000). E. Inner surface of calyx with simple, stellate and glandular trichomes. F–H. Mericarp, dorsal side. F. Biradiate and glandular trichomes. G. Simple, biradiate and stellate trichomes. H. Stellate trichome.

FIGURE 4. Geographical distribution of Peltaea brasiliana (●), Peltaea rupestris (Ì) and Peltaea stellata (▲).