Heteropterys rosmarinifolia R.F.Almeida & M.Pell., 2021

Almeida, Rafael F. & Pellegrini, Marco O. O., 2021, Heteropterys rosmarinifolia, a new species of Malpighiaceae with verticillate leaves from savannas grasslands of central Brazil, PhytoKeys 175, pp. 45-54 : 45

Heteropterys rosmarinifolia R.F.Almeida & M.Pell. sp. nov. Figs 1 , 2 , 3

Diagnosis.

Heteropterys rosmarinifolia differs from the remaining Brazilian species of the Parabanisteria group due to its stems unbranched (vs. branched), leaves associated with the inflorescence verticillate (vs. opposite to subopposite), blades linear to very narrowly oblong (vs. several shapes, but never linear or narrowly oblong), strongly conduplicate (vs. plane), ascending to upright (vs. patent).

Type.

Brazil. Goiás: Cavalcante, Reserva Natural Serra do Tombador , road GO-241, estrada de terra para o Engenho II, a direita da estrada, 13°42'00"S, 47°48'00"W, fl., 25 Jul 2014, R . Sartin et al. 576 (holotype: UFRN barcode UFRN00024927 !; isotype: RB barcode RB01408371 !) .

Description.

Subshrubs 25-55 cm tall, unbranched. Xylopodium not seen. Branches densely rusty-sericeous, hairs adpressed; internodes 0.9-3.6 cm long. Stipules 15-20 mm long, interpetiolar, fused, both sides densely rusty-sericeous. Leaves subopposite at base in vegetative branches, becoming opposite at mid-length, and verticillate towards the apex of the vegetative branches and in flowering branches; petioles 0.2-0.3 cm long, canaliculate, densely rusty-sericeous, eglandular; blades 1.3-8.3 × 0.1-0.3 cm, linear to very narrowly oblong, strongly conduplicate, ascending to upright, coriaceous, eglandular, base obtuse, margins entire, plane to slightly involute, apex obtuse to rounded, sparsely rusty-sericeous to glabrous, abaxially rusty-sericeous, becoming only sparsely rusty-sericeous along the midvein with age. Synflorescence consisting of a solitary main florescence, leaves associated with the inflorescence much reduced, sessile, 3.1-14 × 0.8-1.0 mm. Thyrsi 4-16-flowered, terminal, pedunculate, many-branched; main axis 1.0- 2.8 cm long, smooth, densely rusty-sericeous; bracts 2.0-4.3 × 0.9-1.3 mm, elliptic, concave, patent, eglandular, adaxially glabrous, abaxially rusty-sericeous; cincinni verticillate, 3-4 per node, 1-flowered; peduncle 3.0- 5.1 mm long, rusty-sericeous; bracteoles opposite, inserted at the apex of the peduncle, 2.0-2.5 × 0.5-0.9 mm, elliptic to broadly elliptic, concave, patent, adaxially glabrous, abaxially rusty-sericeous. Flowers 1.0- 1.2 cm diam. at anthesis; floral buds 3.9-5.0 × 2.8-4.0 mm, transversally widely oblongoid to widely depressed ovoid, apex obtuse to truncate; pedicel 5.0-7.0 mm long, rusty-sericeous. Sepals 3.0-4.8 × 1.0- 1.9 mm, straight, smooth, apex rounded, strongly revolute at anthesis, adaxially glabrous, abaxially densely rusty-sericeous; the anterior eglandular, the latero-anterior 1-glandular, the posterior 2-glandular, glands 1.0-1.2 × 0.5-0.6 mm, green, elliptic. Petals bright yellow, dorsally smooth in bud, persistent at anthesis; lateral petals orbicular, plane, limb 3.4-4.2 × 2.7-3.5 mm, margin denticulate, eglandular, claws 1.4-2.2 × 0.4-0.6 mm, both sides glabrous; posterior petal orbicular, erect, limb 3.1-3.5 × 3.0- 3.4 mm, base truncate, margin denticulate, eglandular, claws 1.0-2.1 × 0.6-0.8 mm, both sides glabrous. Stamens 10, all fertile, filaments 2.2-3.0 × 0.2-0.8 mm, basally connate for 0.3-1.2 mm, cylindrical, thicker at base, tapering towards the apex; connective glandular, white, glabrous; thecae 0.8-1.0 × 0.35-0.40 mm, white, glabrous. Ovary 1.4-1.8 × 1.1-1.5 mm, ovoid, densely sericeous; styles 3, erect, 2.4-2.9 × 0.5-0.7 mm, cylindrical, divergent at apex, glabrous, apex rounded, anterior style slightly shorter than posterior ones; stigmas lateral, pointing towards the center of the flower. Fruits not seen. Seeds not seen.

Paratype.

Brazil. Goiás: Cavalcante, Reserva Natural Serra do Tombador , caminho para a cachoeira da Ave Maria, ponto onde se vê a cachoeira, 13°44'26"S, 46°52'46"W, 22 Sep 2015, fl., L . Rocha et al. 668 ( HUEFS barcode HUEFS000273192 !) .

Distribution, habitat, and phenology.

Heteropterys rosmarinifolia is known only from savannas grasslands within the Serra do Tombador Natural Reserve in the State of Goiás, Brazil (Fig. 1 ). It blooms from July to September, but fruits are unknown.

Conservation status.

Heteropterys rosmarinifolia is known only from two collections, probably from the same population within the limits of the Serra do Tombador Natural Reserve in the State of Goiás, Brazil. Until additional fieldwork can be done in the savannas of northern Goiás, this species is best categorized as data deficient ( DD) .

Etymology.

The epithet makes reference to the leaves of the new species that resemble those of the widely cultivated aromatic herb, rosemary ( Salvia rosmarinus Spenn., Lamiaceae ).

Notes.

Heteropterys rosmarinifolia is easily distinguished from the remaining species of the Parabanisteria group by the vegetative characters presented in the abovementioned diagnosis. It is most similar to H. pannosa Griseb. due to its small stature, delicate branches, and narrow leaf-blades. However, it can be differentiated by its stems distally unbranched (vs. branched in the upper half in H. pannosa ), leaf-blades linear to very narrowly oblong, strongly conduplicate, ascending to upright, and abaxially rusty-sericeous (vs. narrowly elliptic, conduplicate, patent, and abaxially greyish-lanate-tomentose), leaves associated with the inflorescence verticillate (vs. opposite to ternate), cincinni verticillate (vs. subopposite to opposite), and anthers glabrous with connectives white (vs. pubescent and brown).

Despite fruits still being unknown for H. rosmarinifolia , they most likely are similar to the ones of H. pannosa , with the dorsal wing reduced to a crest, and nuts lacking lateral winglets (i.e., wingless nut). Alternatively, most species of the Parabanisteria group present a developed dorsal wing ( Almeida et al. 2021). Floral and fruit characters are highly conserved in the Parabanisteria group and have been traditionally considered of little taxonomic relevance ( Niedenzu 1928). Consequently, this group’s taxonomy currently heavily relies on vegetative characters related to life form, branch, and leaf morphology, rendering it the most taxonomic convoluted in Heteropterys ( Niedenzu 1928; Almeida pers. observ.). Further studies are still necessary to properly explore the relevance of floral and fruit characters in this group and review species boundaries. For the time being, we provide below an identification key for the species of Heteropterys from the Parabanisteria group from the State of Goiás, Brazil.

Figures

Figure 1. Heteropterys rosmarinifolia R. F. Almeida & M. Pell. A savannah grasslands from Reserva Natural Serra do Tombador B habit C detail of the apex of the branch, showing the verticillate leaves and solitary inflorescence D cincinnus, showing the concave bracteoles and the floral bud E front view of the flower. All photos by R. Sartin, except A by H. Palo-Jr.

Figure 2. Holotype of Heteropterys rosmarinifolia R. F. Almeida & M. Pell. (R. Sartin et al. 576, UFRN barcode 00024927).

Figure 3. Heteropterys from the Parabanisteria group from the State of Goias, Brazil A H. byrsonimifolia B H. coriacea C H. eglandulosa D H. escalloniifolia E H. nervosa F H. pannosa G H. procoriacea H H. rosmarinifolia. A by L. C. Marinho B, G by I. Morais C, H by R. Sartin D, E by R. F. Almeida F by R. Ripley.