Varronia johnstoniana J.I.M. Melo & D.D. Vieira, 2015

Melo, José Iranildo Miranda De & Vieira, Diego Daltro, 2015, A new species of Varronia (Cordiaceae) and a checklist of Boraginales for the State of Sergipe, Brazil, Phytotaxa 231 (2), pp. 145-155 : 148-149

Varronia johnstoniana J.I.M. Melo & D.D. Vieira , sp. nov. ( Fig. 3 A–F ; Fig. 4 )

Type:— BRAZIL. Sergipe: Areia Branca, Serra de Itabaiana National Park, Serra de Itabaiana, 30 July 2008, fl. fr., T.V.P. Dantas & J.E. Nascimento-Júnior 24 (holotype ASE!).

Sub-shrub to shrub, 0.2–1.5 m tall; cespitose or not. Diffuse branches, subquadrangular or cylindrical, scabrous, glabrous, or generally strigose. Leaves alternate, generally sessile or shortly petiolate; petiole, when present, 0.1–0.3 cm long; blade 3.8–9.1 × 1.5–4.3 cm, leathery, discolorous, shiny, obovate, ovate-lanceolate and elliptical, acute to emarginated apex, margins crenulate to dentate, sometimes slightly revolute, attenuated base, strigose on both faces, with indumentum villose and rufescent, trichomes brown-reddish with bulbous bases, surrounded by a multicellular disk, hyaline, sleek; eucamptodromous venation, with midrib impressed on adaxial face and prominent on abaxial face. Inflorescences spikes or sometimes largely obtrullate, conferring a capitate shape, internodal and axillary, 0.6–7 × 0.9–1.0 cm, pedunculate; peduncle 3.1 × 9.5 cm long, subquadrangular, villous to strigose. Flowers up to 6 mm long, sessile; monoclines, dichlamydeous, actinomorphic. Calyx up to 5 mm long, gamosepalous, oblong-campanulate, externally villous with brown-reddish trichomes on the floral tube, internally villous in the region of the lacinias, with rufescent indumentum; lacinias broadly elliptical with two size classes, being three smaller lacinias, ca. 1.5 mm long, and two larger lacinias, 2.0 mm long, with apex caudate and blackish; corolla ca. 5.5 mm long, funnel-shaped to salverform, externally villous, with brown-reddish trichomes, internally villous at the insertion region of the filaments, with brown trichomes; lobes 1 mm long, orbicular. Stamens 5, epipetalous, free among themselves, filaments 2 mm long; anthers 1.2 × 0.5 mm, oblong, brown, oblique. Gynoecium ca. 3.5 mm long; ovary ca. 1.5 mm long, deep-trullate; style ca. 1.5 mm long, forking at ca. 1.2 mm, with 4 stigmatic branches, each ca. 0.3 mm long. Stigmas 4, ca. 0.5 mm long, capitate. Drupe 3.5 × 2.0 mm, pear-shaped, verrucose, with style debris, red when ripe, carpopodium ca. 1 mm long; seeds not observed.

Habitat and Distribution:— Occurs in the Brazilian state of Sergipe, being mainly found in the area of the Serra de Itabaiana National Park in the semiarid domain. It is associated with Caatinga vegetation on shallow, sandy soils and rock outcrops, sometimes forming thickets, as well as areas of Restinga vegetation situated on the northern coast of that state.

Conservation Status:— Varronia johnstoniana is known from many populations recorded over at least 35 years in areas of Caatinga vegetation in the Serra de Itabaiana National Park. It is also associated with sandbank vegetation formations (Restinga) along the coast that are greatly threatened by real estate speculation; it can thus be classified as Critically Endangered ( CE), Criterion B1 (a), due to habitat destruction and the scarcity of samples for this vegetation type ( IUCN 2001).

Phenology:— Flowers in April, May, July, and August, with fruiting from February to April and from July to November.

Etymology:— The specific epithet was given in honor of Dr. Ivan Murray Johnston, a botanist from Harvard University, USA, who has dedicated almost four decades (between the 1920’s and 1950’s) to studying the family Boraginaceae .

Additional examined specimen (paratypes):— BRAZIL. Sergipe: Areia Branca, Serra de Itabaiana Ecological Station ( ESEC), 16 September 1995, fr., M. Landim et al. 663 ( ASE). Itabaiana , 24 October 1974, fr., A.C. Barreto s.n. ( ASE 151 ) ; Itabaiana, Serra de Itabaiana , 23 March 1978, fr., A.A. Carlos s.n. ( ASE 563 ) ; Itabaiana, Serra de Itabaiana National Park ( PARNA), 10º45’08”S – 37º20’27,9”W, 231 m, 21 July 2006, fl. fr., S. Schmidt et al. 244 ( ASE, UFP). Japaratuba, Sapucaia, 23 July 2013, est., E. Santos et al. 07 ( ASE). Santo Amaro das Brotas, 22 February 1978, fr., M. Fonseca s.n. ( ASE 532 ). Serra de Itabaiana , 16 April 1985, fl. fr., G. Viana 1121 ( ASE) ; Serra de Itabaiana National Park ( PARNA), 5 August 2007, fr., E.C.A. Matos et al. 36 ( ASE) ; Serra de Itabaiana National Park ( PARNA), 1 August 2008, fl., J.E. Nascimento-Júnior et al. 260 ( ASE). Riacho dos Negros, 1 May 1991, fl., M.L. Santos 92 ( ASE) .

Discussion:— Varronia johnstoniana can be distinguished from other congenerous species (especially representatives with spike inflorescences, but principally from Varronia curassavica Jacquin [1760: 14] , which is morphologically related) by the following vegetative and reproductive features: sessile leaves, with leathery and shiny leaf blades, crenulate to dentate margins that are sometimes slightly revolute, inflorescence of the spike type, or largely obtrullate, sometimes appearing capitate, indumentum rufescent, villose, consisting of brown-reddish trichomes with bulbous bases on the calyx and corolla, calyx oblong-campanulate with caudate lacinias and blackish apices, corolla ca. 5.5 mm long, orbicular lobes, and verrucose fruits (versus chartaceous leaf blades with serrate margins, planar, inflorescence exclusively of the spike type, calyx campanulate, pubescent, lacinias obtuse to emarginate towards the apex, not caudate, corolla 3–5 mm long, glabrous, lobes ovate, and fruit flat surfaced in V. curassavica ).

The presence of V. johnstoniana in both Caatinga and Restinga regions is probably due to the soil type (predominantly sandy) shared by these two formations; but this species has mainly been recorded in the Serra de Itabaiana National Park in the semiarid region of Sergipe State, Brazil .

Figures

FIGURE 3. A–I Boraginales species of Sergipe State, Brazil. A. Cordia sellowiana. B. C. trichotoma. C. Euploca polyphylla. D. Heliotropium elongatum. E. Myriopus salzmannii. F. M. villosus. G. Tournefortia bicolor. H. Varronia curassavica. I. V. leucocephala. (Photos: A, H, I, D.D. Vieira; B, L. Nusbaumer; C–E, J.I.M. Melo; F, L. Cavalheiro; G, J.D. García G.).

FIGURE 4. A–B Varronia johnstoniana. A. Holotype (J.E. Nascimento-Júnior et al. 976). B. Detail of the inflorescence types.