Microlicia piatensis Almeda & R.B.Pacifico, 2022

Pacifico, Ricardo & Almeda, Frank, 2022, New species of Marcetia and Microlicia (Melastomataceae) endemic to the campo rupestre of Chapada Diamantina, Bahia, Brazil, Phytotaxa 573 (1), pp. 39-69 : 58-60

Microlicia piatensis Almeda & R.B.Pacifico , sp. nov. ( Figs. 18–19 ).

Type:— BRAZIL. Bahia: Piatã , caminho para os Três Morros , estrada para Inúbia , 13°04’36.8”S, 41°54’21.1”W, 1376 m, 19 June 2022, fl., fr., R. Pacifico 659 & V.E. Bressan (holotype: HUEM!, isotypes: ALCB!, CAS!, HUEFS!, RB!).

Diagnosis:—Differs from Microlicia sulfurea Hoehne (1922: 22) by the elliptic leaf blades (vs. ovate to lanceolate), anthers oblong (vs. oblong-linear), shorter antesepalous pedoconnectives 1.4–1.9 mm long (vs. 3.8–4.2 mm long), antesepalous appendages 0.5–0.8 mm long that are bilobate at the apex (vs. 1–1.2 mm long, apex truncate), and shorter antepetalous pedoconnectives 0.6–0.9 mm long (vs. 1.5–2 mm long).

Erect shrubs 0.5–1.5 m tall, much-branched. Upper cauline internodes 1.5–3 mm long, light green (when fresh) becoming pale green (when dry) and defoliated with age, quadrangular, not sulcate, unwinged, densely glandularpunctate. Leaves decussate, ascending, not concealing uppermost internodes (both when fresh and when dry), chartaceous, concolored, light green (when fresh) becoming pale green (when dry); petioles 0.4–0.7 mm long, light green, flattened; blades 2.5–3 × 1–1.5 mm, elliptic, apex rounded, base cuneate, margins entire and glandular-punctate, flat, both surfaces densely glandular-punctate, 1-nerved, venation impressed on both surfaces, secondary venation not evident. Flowers 5(–6)-merous, on short pedicels 0.2–0.4 mm long (these lengthening to 1 mm long in fruit), apical, solitary, ebracteolate. Hypanthia (at anthesis) 2.8–3.1 mm long, 2.2–2.5 mm wide at the torus, light green (when fresh) becoming pale brown in fruit (and when dry), campanulate, equaling the capsule in length at maturity, densely glandular-punctate. Calyx tubes ca. 0.2–0.3 mm long. Calyx lobes 1–1.5 mm long, 1.3–1.7 mm wide at the base, light green (when fresh) becoming pale brown (when dry), nearly erect at anthesis, triangular, apex acute and mucronate, margins entire and glandular-punctate, externally glandular-punctate. Petals 4–5 × 3–4 mm, obovate, yellow, base attenuate, apex truncate, both surfaces glabrous, margins entire and glabrous. Stamens 10(12), entirely yellow, dimorphic, antesepalous anthers ± horizontal (at anthesis), subparallel and clustered, antepetalous anthers ± erect and clustered near the floral axis; antesepalous (larger) stamens with filaments 2–2.5 mm long, glabrous, thecae (excluding rostra) 1.6–1.9 × 0.4–0.5 mm, oblong, corrugate (polysporangiate), rostra 0.2–0.3 mm long, the ventrally inclined pores ca. 0.1 mm wide, nearly circular, pedoconnectives 1.4–1.9 mm long, appendages 0.5–0.8 mm long, apex bilobate; antepetalous (smaller) stamens with filaments 1.5–1.9 mm long, glabrous, thecae (excluding rostra) 1.5–2 × 0.3–0.5 mm, corrugate (polysporangiate), oblong, rostra 0.2–0.3 mm long, the ventrally inclined pores 0.1–0.2 mm wide, nearly circular, pedoconnectives 0.6–0.9 mm long, appendages 0.2–0.3 mm long, apex emarginate. Ovary (at anthesis) ca. 1 × 0.8 mm, superior, subglobose, glabrous, 3-locular, not adnate to the hypanthium; style 4–5 mm long, yellow, glabrous, sigmoid, stigma punctiform. Fruit at maturity a globose loculicidal capsule 1.5–2 × 1.3–1.7 mm, pale brown, ovoid, 3-valvate, enveloping hypanthia and rupturing and flaking away with age, dehiscent from the apex to the base (basipetal), columellas deciduous. Seeds ca. 0.3–0.4 × 0.2 mm, yellow, oblong, testa foveolate, raphal zone nearly circular, ca. 30% the length of the seed.

Additional specimens examined: BRAZIL. Bahia: Piatã. Serra do Atalho, próximo ao Garimpo da Cravada, 13°07’S, 14°54’W, 1400 m, 21 August 1992, fl., fr., W. Ganev 933 ( HUEFS!, SPF!, UEC!, US!); caminho para os Três Morros , 13°03’39”S, 41°52’49”W, 19 September 2004, fl., fr., M.L. Guedes et al. 11236 ( ALCB!, MBM!); caminho para os Três Morros , 13°03’39”S, 41°52’49”W, 18 September 2004, fl., fr., M.L. Guedes et al. 11240 ( ALCB!, MBM!); caminho para os Três Morros , estrada para Inúbia , 13°04’36.8”S, 41°54’21.1”W, 1376 m, 19 June 2022, fl., fr., R. Pacifico 658 & V.E. Bressan ( CAS!, HUEM!, HUEFS!, RB!); Chapada Diamantina , Serra de Santana, 2 km de Piatã, 13°07’45”S, 41°46’34”W, 5 December 2003, fl., fr., N. Roque et al. 888 ( ALCB!, MBM!).

Distribution, habitat and phenology:— Probably restricted to the mountains of Piatã, Bahia , Brazil ( Fig. 12 , Appendix 2). It grows in campo rupestre ( Fig. 4 ) exposed to full sun at elevations between 1350–1400 m. Microlicia piatensis was collected flowering and fruiting in June, August, September and December.

Etymology:— The specific epithet refers to its distribution which is apparently restricted to Piatã, Bahia , Brazil ( Fig. 12 ).

Notes:— Besides M. sulfurea ( Fig. 5G ) and M. prostrata (see diagnoses of M. piatensis and M. prostrata , respectively), Microlicia piatensis is also possibly related to M. parvula ( Markgraf 1927:44)Koschnitzke &A.B.Martins (2007: 474) ( Fig. 5F ). Both M. piatensis and M. parvula have an erect habit, a glandular-punctate indumentum on branches, leaves and hypanthia, somewhat elliptic leaves, triangular calyx lobes, yellow petals, and yellow stamens with polysporangiate thecae. Microlicia piatensis can be differentiated by its leaves with conspicuous petioles 0.4– 0.7 mm long (vs. petioles absent or inconspicuous, up to 0.2 mm long), and dimorphic stamens with conspicuous pedoconnective appendages (vs. isomorphic to subisomorphic, inconspicuous appendages). Among the compared species, only M. parvula apparently grows sympatrically with M. piatensis in Piatã, Bahia (see Appendix 1).

Suggested conservation status:— Critically Endangered (CR): B1ac(iii)+B2ac(iii) (see Appendix 2).

Figures

FIGURE 4. Landscapes with campo rupestre vegetation in Chapada Diamantina, Bahia, Brazil. A. Serra da Batávia, Mucugê – type locality of Marcetia auricularia and Microlicia daneui. B. Serra do Barbado,Abaíra – type locality of Marcetia santosiae. C. Pico do Elefante,Abaíra – type locality of Microlicia prostrata (in the background, Serra do Barbado). D. Serra do Porco Gordo, Arapiranga (Rio de Contas) – type locality of Microlicia tetramera. E. Serra do Esbarrancado, Guiné (Mucugê) – type locality of Marcetia unguiculata. F. Serra do Gobira, Mucugê. Photos:A, by U. Marques; B–F, by R. Pacifico.

FIGURE 5. Selected photos of species compared to new taxa described in this study. A–B. Marcetia nummularia. A. Habit. B. Flower close up. C. Microlicia obovatifolia, flower close up. D. Microlicia cryptandra, flowering branch. E. Microlicia noblickii, flower close up. F. Microlicia parvula, flowering branch. G. Microlicia sulfurea, flowering branch. H. Microlicia juniperina, flowering branches. Photos: A–B, E, H, by R. Pacifico; C–D, F, by F. Almeda; G, by J.A. Siqueira Filho (HVASF herbarium).

FIGURE 12. A. Brazil with Bahia state highlighted. B. Bahia with the study area outlined (dashed line). C. Distributions of Microlicia ascendens, Microlicia daneui and Microlicia piatensis in the Chapada Diamantina, Bahia, Brazil.

FIGURE 18. Microlicia piatensis, photos of living plants. A. Flowering branches. B. Close up of a flower. C. Branch terminating in a floral bud and one capsule. D. Branch terminating in a flower at anthesis in lateral view. E. Branch with capsule enveloped by the hypanthium.All photos by R.Pacifico. Voucher: R. Pacifico & V.E. Bressan 659.

FIGURE 19. Microlicia piatensis, photos of dry specimens. A. Habit. B. Detail of branchlet. C. Leaf adaxial surface. D. Leaf abaxial surface. E. Flower in lateral view. F. Flowering hypanthium and calyx lobes. G. Petal adaxial surface. H. Antesepalous stamen. I. Antepetalous stamen. J. Capsule enveloped by the hypanthium. Scale bars: A, 2 cm; B–D, H–I, 1 mm; E–G, J, 2 mm. Vouchers: A, W. Ganev 933; B–J, M.L. Guedes et al. 11240.