Mcvaughia bahiana W.R.Anderson, Taxon 28: 157. 1979

Almeida, Rafael F., Guesdon, Isabel R., Pace, Marcelo R. & Meira, Renata M. S., 2019, Taxonomic revision of Mcvaughia W. R. Anderson (Malpighiaceae): notes on vegetative and reproductive anatomy and the description of a new species, PhytoKeys 117, pp. 45-72 : 45

1. Mcvaughia bahiana W.R.Anderson, Taxon 28: 157. 1979 Figs 5 , 6 , 11

Type.

BRAZIL. Bahia: Conceição do Coité, road from Coité, 12 km to Santaluz, fl. Fr., 6 Mar 1976, W.R. Anderson 11740 (holotype: MBM barcode MBM59835!; isotypes: F barcode F0062743F!, G barcode G00352842!, K barcode K000426948!, MICH barcode MICH1102251!, NY barcode NY00067680!, P barcode P02429273!, RB barcode RB00540751!, SP barcode SP000249!, U barcode U0003826!, UB barcode UB1950!, US barcode US00108758!).

Description.

Shrubs 1-3 m tall. Branches densely sericeous, glabrescent at age. Stipules 2.5-5 mm long, adaxially glabrous, abaxially sericeous. Leaves opposite; leaf blades 4.5-8.8 × 2-5 cm, chartaceous to subcoriaceous, elliptic to obovate, base cuneate to rotund, margins plain, entire, apex acute to apiculate, adaxial side initially tomentose, glabrous at age, abaxial side densely tomentose, a pair of conspicuous glands at base abaxially, on each side of the midrib, a few inconspicuous glands scattered over the blade, with 1-3 glands near the apex; petiole 0.3-0.7 cm long, canaliculate, densely tomentose, eglandular. Thyrsi of 2-7-flowered cincinni; rachis 3-10 cm long, smooth, densely tomentose, with brown hairs; lateral cincinni 12-24, subopposite; bracts 2-7 mm long, narrowly-triangular, appressed to the peduncle, eglandular, tomentose; peduncle 1.5-4.5 mm long, tomentose; bracteoles 1.5-2.5 mm long, narrowly triangular, opposite, appressed to the peduncle, tomentose, one of each pair bearing a conspicuous gland at base, 1-1.2 mm long. Flowers 1-1.2 cm diam. at anthesis, floral buds 3-3.2 mm long, pedicel 0.5-1.7 mm long, tomentose. Sepals 2-3 × 1.5-2.5 mm, straight, keeled, covering most of the androecium, apex acute, margin glabrous, adaxial side glabrous, abaxial side tomentose, glabrescent near the margin; 10-glandular, glands 1.5-2.5 × 0.7-0.8 mm, yellow, elliptic. Petals yellow, both sides glabrous, soon deciduous; anterior lateral petals orbicular, cucullate, nested inside one another, limb 3-3.3 × 4.5-4.7 mm, margin denticulate, 2-glandular at base, claws 1.2-1.5 × 0.2-0.25 mm, glabrous; posterior lateral petals obovate, spreading, limb 5.5-6.5 × 6-7 mm, margin erose, 2-glandular at base, claws 1.8-2 × 0.3-0.35 mm, glabrous; posterior petal obovate to orbicular, erect, limb 6-7 × 7-8 mm, margin erose, 3-5 pairs of rounded glands at the base of limb, proximal pair larger, claws 3-4 × 0.7-0.9 mm, both sides glabrous. Stamens free at base, filaments 2-3 × 0.2-0.4 mm, cylindrical, thicker at base; connective inconspicuous, glabrous; anthers 0.7-1 × 0.4-0.45 mm; staminodes opposite the posterior-lateral sepals covered by sepals, filaments ca. 1 mm long, long-triangular, anthers ca. 0.2 mm long, oblong, locules lacking; staminode opposite the posterior petal not covered by sepals, exserted, diverging from styles, filament 2-2.1 × 0.2-0.4 mm long, anther 0.25-0.3 mm long, oblong, locules reduced. Ovary 1-1.3 × 1-1.3 mm, ovoid, densely sericeous; styles 3, erect, ca. 2.5-2.7 × 0.5-0.6 mm, cylindrical, parallel, glabrous, apex truncate, anterior style slightly smaller than posterior ones; stigma lateral, circular. Drupes 7-8.5 × 4-5 mm, cylindrical, slightly twisted, apex with persistent styles, sparsely tomentose, with two chambers, proximal chamber containing the seed, distal chamber containing an oily substance; seed globose, smooth. Embryo not seen.

Specimens seen.

BRAZIL. Bahia: Itiúba, 20 km de Camaleão para Cansanção, 330 m, fl., 26 Feb 2000, A.M. Giulietti 1827 (CEN, FLOR, HUEFS, RB, UB); 20 Km East Camaleão, Rod. Itiúba/Cansanção, 21 Feb1974, fl., R.M. Harley 16465 (CEPEC, MICH, NY, P, RB). Monte Santo, Fazenda Bom Jesus, fl. fr., 11 Oct 2000, C.M.L. Aguiar 17, 18, 19, 27, 28, 30, 31 (HUEFS); fl. fr., 12 Jan 2006, M.L. Guedes 12148 (ALCB). Quijingue, Serra das Candeias, 5 Km W povoado Quixabá do Mandacaru, near Tucano, fl. fr., 15 May 2005, D. Cardoso 529 (HUEFS); fl. fr., 8 Jul 2006, D. Cardoso 1311 (HUEFS). Tucano, povoado Bizamum, 23 km from Tucano, fl. fr., 6 Jun 2004, D. Cardoso 57, 99 (HUEFS, SP); povoado Marizá, 13 km from Tucano, fl. fr., 6 Jan 2006, D. Cardoso 958 (HUEFS, RB); distrito de Caldas do Jorro, estrada entre Caldas do Jorro e rio Itapicurú, fl. fr., 1 Mar 1992, A.M. Carvalho 3863 (CEPEC, HUEFS, MBM, NY, SP); fl., 15 March 2008, G. Costa 341 (HST, HUEFS); povoado Bizamum, fl., 6 Feb 2004, L.P. Queiroz 9017 (HUEFS); povoado Bizamum, fl. fr., 22 Sep 2015, I.R. Guesdon 300, 301 (VIC).

Distribution, habitat, and phenology.

Mcvaughia bahiana is known only from sandy caatingas (seasonally dry forests) within northeastern state of Bahia, Brazil (Fig. 11 ). Flowering and fruiting throughout the year.

Conservation status.

Mcvaughia bahiana shows an extent of occurrence of 2,527 km2, and an area of occupancy of 16.000 km2 within the northeastern state of Bahia, Brazil. Its restricted distribution associated with an accelerated habitat degradation categorizes it as Endangered (EN). Mcvaughia bahiana is the only species in the genus not protected within the limits of a conservation unit.

Etymology.

The epithet refers to the distribution of M. bahiana , which is restricted to the state of Bahia, Brazil.

Anatomical notes.

Leaf glands are distributed throughout the leaf blade. Two basilaminar glands are typically positioned in pairs and visible to the naked eye (Fig. 3A ). However, the anatomical study revealed a few additional glands distributed distally and difficult to see with the naked eye, two or three of them positioned subjacent to the apical leaf tooth. Anatomically, the basilaminar and laminar glands are short-stalked (Fig. 3D, J ). The section of the bracteole and sepal glands revealed a subsessile anatomical structure (Fig. 4E ). Malpighiaceous trichomes and their scars are frequent on the leaf, especially on the abaxial surface (Fig. 3O ). On mature leaves, the indumentum along the middle and secondary veins and the apical leaf tooth is typically tomentose. The outline of the anticlinal walls is straight on the adaxial surface and sinuous on the abaxial (Fig. 3Q ). Field observations revealed that the leaf glands are yellow, while the bracteole and sepal glands are green becoming yellow in blooming. The glands on the posterior petal are restricted to the proximal portion of the limb, where ca. 5 marginal glands were observed on each side of the petal limb (Fig. 4L, O–P ).

Figures

Figure 3. Leaf morphoanatomy of Mcvaughia species. A patterns of leaf glands distribution on the abaxial leaf surface of M. bahiana B patterns of leaf glands distribution on the abaxial leaf surface of M. piauhiensis C patterns of leaf glands distribution on the abaxial leaf surface of M. sergipana D transverse section of leaf base showing the basilaminar pair of stalked glands (white arrows) E basilaminar leaf gland with a stalk (black arrow) in M. piauhiensis F basilaminar gland in M. sergipana showing a sessile position (SE = anatomical arrangement with secretory epidermis, SP = vascularized secretory parenchyma) G-H laminar glands on the apex of cleared leaves of M. sergipana and M. bahiana respectively, note the apical tooth (G) I sessile laminar glands in M. sergipana J stalked laminar gland in M. piauhiensis K-L transverse sections of the leaf blade; mesophyll with uniserial palisade-like parenchyma and spongy parenchyma composed by several or few layers in M. sergipana and M. bahiana, respectively; note the idioblast with druse crystals at the mesophyll (white arrow) and the stomata distribution at the abaxial leaf surface (black arrow) M-N adaxial epidermis surface of M. piauhiensis and M. sergipana, showing scars of malpighiaceous trichomes O abaxial epidermis surface of trichomes abundance in M. bahiana P-Q outline of the anticlinal epidermal cell walls: straight in M. sergipana (P) and sinuous in M. bahiana (Q). Laminar scale bars: 1 cm (A-C), 100 μm (D, F-K, N-O), 150 μm (E), 50 μm (L-M, P-Q).

Figure 4. Reproductive morphoanatomy of Mcvaughia species. A inflorescence during development, showing a bracteole gland (BG) and Sepal glands (SG) B ten sepal glands encircling the calyx C Petal glands (PG) along the margin of posterior petal D-F transverse section of bracteole glands in M. sergipana, M. bahiana and M. piauhiensis, respectively G anatomical arrangement of bracteole gland, with a palisade-like secretory epidermis (SE) and secretory parenchyma (SP) H-I transverse section of floral bud and anthesis flower in Mcvaughia bahiana and M. sergipana; calyx gland pair displaced at the anterior sepal J calyx gland structure, showing a secretory epidermis (SE) and vascularized secretory parenchyma (SP) K-L petal glands on the margin of petals in M. sergipana and M. bahiana respectively M-N detail of the petal glands at the apex of the petal limb in M. sergipana, cleared and in SEM image O-Q petal glands positioned at the base, M. bahiana on SEM image, M. bahiana and M. piauhiensis cleared R-T conspicuous and stalked petal glands at the base of M. sergipana, in SEM image, cleared and longitudinal section. Scale bars: 200 μm (D), 150 μm (E-F), 50 μm (G), 500 μm (H-I), 100 μm (J, P-S), 300 μm (L-M), 200 μm (N, T).

Figure 5. Mcvaughia bahiana. A shrub habit B subshrub habit C inflorescence showing glandular bracts D inflorescence showing flowers in anthesis E inflorescence showing immature and mature fruits F detail of mature fruits G drupe indumentum H glabrescent drupe. A, D-H by W. R. Anderson B-C by I. R. Guesdon.

Figure 6. Photograph of the isotype of Mcvaughia bahiana.

Figure 11. Distribution map of Mcvaughia: triangle - M. bahiana, circle - M. piauhiensis, and square - M. sergipana. Solid blue line in the center represents the Sao Francisco River today. Dotted blue line represents the past course of Sao Francisco River. Blue circle represents the Sao Francisco paleo lake. Light green - Atlantic Forest domain, dark green - Amazon Forest domain, orange - Cerrado domain, and yellow - Caatinga domain. AL - state of Alagoas, BA - state of Bahia, CE - state of Ceara, MA - state of Maranhao, PB - state of Paraiba, PE - state of Pernambuco, PI - state of Piaui, RN - state of Rio Grande do Norte, and SE - state of Sergipe.