Blakea cubarralensis Urrea & L. Carvajal, 2024

Urrea, Johan, Mendoza-Cifuentes, Humberto, García, Néstor & Rojas, Lyndon Carvajal, 2024, Blakea cubarralensis (Melastomataceae: Pyxidantheae): a new species from Colombia, Phytotaxa 666 (1), pp. 59-66 : 60-63

Blakea cubarralensis Urrea & L. Carvajal , sp. nov. ( Figs. 1–2 )

Type: — COLOMBIA. Meta: Municipio de Cubarral, vereda El Vergel Alto , 1795 m, 2 September 2003, bud, fl, W. Ariza & J. Navarro 436 (holotype: UDBC!; isotypes: COAH!, COL!, FMB!) .

Diagnosis:— Blakea cubarralensis is characterized by its hemiepiphytic shrubby habit, with pedicels 4–6.4 mm long, floral bracteoles coriaceous and exceeding the calyx lobes, outer pair ovate-elliptic with apex long acuminate, conspicuously 3-nerved, calyx 6- lobulate, anther connective prolonged 0.4–0.6 mm into a blunt knob and ovary 12-locular. It is similar to Blakea truncata Gleason (1933: 46) but differs in the length of pedicels (4–6.4 mm long vs. 29–40 mm long in B. truncata ), the morphology of outer bracteoles (ovate-oblong with apex long acuminate vs. ovate with apex acute in B. truncata ) and calyx morphology (6-lobulate vs. truncate in B. truncata ).

Hemiepiphytic shrubs, with sympodial growth. Internodes quadrangular, 13–35 mm long, young ones densely cover with smooth elongated trichomes 0.6–1 mm long, glabrous with age; nodes 3–4.5 mm diam., not swollen, with visible interpetiolar line. Leaves opposite, decussate, isophyllous; petioles 1.3–2.1 cm long, terete, sulcate, glabrous; leaf blades 8.9–12.2 × 5–7.1 cm, subcoriaceous, elliptic, elliptic-oblong or elliptic-obovate, base acute to slightly decurrent, apex acuminate, margin entire and slightly revolute when dry, upper surface glossy, lower surface dull; venation acrodromous and basal or slightly suprabasal, with one pair of secondaries (lateral) veins, plus one outermost pair faint and submarginal, innermost pair diverging 0–15 mm from the base of the blade, percurrent tertiary (transversal) veins spaced 0.2–1.4 mm at the widest portion of the blade, midvein and secondary veins impressed, tertiary veins barely visible and reticulation not visible on the adaxial surface, midvein and secondary veins elevated, tertiary veins and reticulation visible on the abaxial surface; both surfaces glabrous; domatia absent. Inflorescences axillary, fasciculate in distal nodes, each axil with 1–3 flowers; pedicels 4–6.4 mm long, quadrangular, glabrous; floral bracteoles coriaceous, persistent, glabrous; outer pair 20–22 × 8.5–12.8 mm, longer than the calyx lobes, basally connate by 3.2–3.4 mm, ovate-elliptic, apex long acuminate, 3-veined, proximally adherent to the hypanthium, spreading distally; inner pair 10.5–11.5 × 8.5–12.8 mm, as long as the calyx lobes, free, overlapping basally, orbicular, apex rounded to acute, multinerved, adherent to the hypanthium. Flowers 6-merous, erect. Hypanthium 5.2–5.8 × 8.7–12.2 mm, campanulate, glabrous; inner hypanthium 1.4–2.5 mm, glabrous. Calyx lobulate, glabrous; tube 1.9–2.3 mm long; lobes 1.5–2.2 × 5–5.6 mm, orbicular, apex rounded and mucronate, margin entire, venation with midvein and reticulation, without appendages nor dorsal projections. Corolla rotate; petals 16.5–18.5 × 16–16.5 mm, imbricate, obovate-oblong, apex rounded, margin entire, surface smooth, glabrous, white with pink apex. Stamens 12, isomorphic, bent to one side of the flower forming a ring of ca. 180°; filaments 7.5–8.6 mm long, flattened, glabrous, white; connective rugose, prolonged 0.4–0.6 mm dorso-basally into a blunt knob, white; anthers 4.5–5 × 3.4–4.2 mm, laterally connate, compressed, orbicular to oblong in lateral view, apex obtuse, articulating to the filament at a right angle, thecae cream, with smooth surface, opening by two well separated apical pores; pores 0.2–0.3 × 0.2–0.3 mm, circular, separated by 0.7–1 mm. Ovary inferior, 12- locular, locules 3–3.4 × 8.2–11.9 mm, apex truncate, without an apical collar, roof of ca. 1 mm long; style 14–14.5 mm long, columnar, curved distally, glabrous; stigma 0.2–0.3 × 0.3–0.4 mm, punctiform. Berries ca. 14–18 × 11–15 mm, obconical, glabrous, red when mature; seeds ovoid, testa smooth.

Etymology:— This species is named after the municipality of Cubarral, Meta, where the largest known population of the species is found within The Palmeras Natural Reserva and where the type specimen was collected.

Distribution and habitat:— Blakea cubarralensis is known from sub-andean forest in the department of Meta, on the eastern slopes of the Eastern Cordillera between 1600 and 1800 m ( Fig. 3 ). The species is found in very humid premontane forests, with a relatively humidity of more than 90% and temperatures between 11 to 24 °C ( Carvajal Rojas & Ledesma 2021). This species grows mainly inside primary forests or secondary forests with long restoration processes. Considering its hemiepiphytic growth habit, it is sensitive to habitat transformation and rely on big trees to establish.

Phenology:— Flowering occurs in April, May, July, September, and November; fruiting in May and November.

Conservation status:— Blakea cubarralensis has an EOO of 221 km 2 and it is currently known in four localities in the department of Meta. It is threatened by habitat fragmentation and transformation for agricultural and livestock activities. At three of its known localities, there is evidence of a continuous decrease in habitat quality. The populations growing around Villavicencio, Acacias, and the urban areas of Cubarral are located in highly fragmented areas surrounding agricultural and livestock systems. No records have been reported in the Villavicencio locality since 1993. In Cubarral, within The Palmeras Natural Reserve, the species grows inside a protected area of 250 ha, that has primary and disturbed forests that have been in the process of natural restoration for over 10 years. Considering the EOO, the small numbers of locations and the estimated decline in the quality of habitat, Blakea cubarralensis is categorized in Endangered (EN) according to the criteria B (B1ab(iii)) of the IUCN Red List ( IUCN 2012).

It is important to mention that the largest known population of Blakea cubarralensis occurs inside The Palmeras Reserve, which is the primary conservation measure currently implemented for this species. The reserve is a protected area established in 2009, with humid premontane forests, which had been characterized as a transition zone between three regions: Orinoquia, Amazonia and the Andes ( Carvajal Rojas & Ledesma 2021). The reserve was established to protect a population of yellow-eared parrots ( Ognorhynchus icterotis ), and since then, a range of conservation, monitoring, and environmental education initiatives have been implemented that actively involve local communities to foster the preservation and enhancement of the biodiversity of the region ( Carvajal Rojas & Ledesma 2021).

Comments:— Blakea cubarralensis is distinguished by the ovate-elliptic outer floral bracteoles with long acuminate apex, which is longer than the calyx lobes and partially covers the hypanthium, anther connective prolonged 0.4–0.6 mm dorso-basally into a blunt knob, and 12-locular ovary. It is similar to Blakea truncata due to the big bracteoles, longer than the calyx lobes, but differs in the characters listed in the diagnosis and the 12-locular ovary (vs. 6-locular in B. truncata ). It also appears to be related to Blakea latifolia ( Ruiz & Pavon 1830: 407) Don (1823: 325) , but it is distinguished by the length and morphology of floral bracteoles (vs. both pairs shorter than calyx lobes with acute apex in B. latifolia ) and stamens bent to one side forming a ring of ca. 180° (vs. stamens forming a complete circle of 360° in B. latifolia ). Despite the morphological similarity, there are no populations of B. cubarralensis , B. truncata and B. latifolia in the same area. Blakea truncata is distributed further south along the Cordillera and B. latifolia is found at lower elevations ( Fig. 3 ).

Blakea cubarralensis is also slightly similar to B. rosea ( Ruiz & Pavon 1830: 408) Don (1823: 325) , but differs in the length of pedicels (vs. 8.2–21 mm long in B. rosea ), morphology of the floral bracteoles (outer pair ovate-oblong with apex acute and multinerved in B. rosea ) and obovate-oblong petals 16.5–18.5 mm long, with a rounded apex (vs. obovate, 14.5–15.3 mm long, with an acute apex in B. rosea ).

In Blakea cubarralensis there is some morphological variation at the population level with some specimens having more elliptic to obovate leaf blades, slightly decurrent base, green margins and the leaves turning yellow when mature, whereas the typical form has elliptic to elliptic-obolong leaf blades, acute base, red margin and turning red when mature. These populations also have smaller floral bracteoles, the outer pair with the apex of the acumen acute, whereas the typical form has a more rounded apex of the acumen. These differences do not appear to be taxonomically significant, considering that diagnostic characters are shared among all individuals.

Additional specimens examined (paratypes):— COLOMBIA. Meta: Municipio de Acacias, vereda Venecia, cerca de finca don Gregorio , 4°8’20.8”N, 73°51’14.69”W, 1905 m, 28 March 2014, E. Sastoque et al. 85 ( UDBC). Municipio de Cubarral , vereda El Vergel Alto, 1660 m, 1April 2009, L. Carvajal 1117 ( COL, UDBC) ; 3°51’0.7”N, 73°53’86.7”W, 1675 m, 11 November 2011, L. Carvajal 2532 ( UDBC) ; 23 September 2018, L. Carvajal 4070 ( UDBC) ; Reserva Natural Las Palmeras , 3°51’32.8”N, 73°53’57.3”W, 1800 m, 2 April 2017, A. Torrejano & C. Homizda 241 ( UDBC) ; 3°51’36,4”N, 73°53’58,3”W, 1810 m, 5 April 2023, A. Torrejano et al. 1127 ( UDBC, HPUJ, JBB) ; 3°51’31.2”N, 73°54’32.4”W, 1607 m, 10 April 2017, L. Carvajal 3786 ( UDBC) ; 1650 m, 20 November 2014, L. Carvajal 3071 ( UDBC) ; 1 April 2023, L. Carvajal 43541 ( UDBC) ; 21 April 2024, L. Carvajal 4724 ( UDBC) ; Finca Las Palmeras, 1300-1900 m, 17 July 2008, F. Rojas et al. 106 ( UDBC). Municipio de Villavicencio, camino a la vereda Monfort , 4°4’N, 73°48’W, 1500–1700 m, 31 May 1993, D. Restrepo 824 ( COAH, COL) .

Figures

FIGURE 1. Lankester Composite Digital Plate (LCPD) Blakea cubarralensis. A. Flower at anthesis. B. Calyx lobes. C. Petals. D. Flower at anthesis without petals. E. Floral bracteoles: E1. Outer pair. E2. Inner pair. F. Lateral view of flower at anthesis without bracteoles and petals. G. Gynoecium. H. Ovary locules. I. Stamen in lateral view. J. Detail of the anther. K. Mature fruit. Photographs by Lyndon Carvajal Rojas and Luis Rodríguez Correa. Plate by Luis Rodríguez Correa.

FIGURE 2. Lankester Composite Digital Plate (LCPD) Blakea cubarralensis. A. Reproductive branch. B. Shapes, sizes, and colors of leaves. C. Young node. D and E. Flower buds. F. Longitudinal section of flower bud showing young gynoecium, androecium, and petals. Photographs by Lyndon Carvajal Rojas and Luis Rodríguez Correa. Plate by Luis Rodríguez Correa.

FIGURE 3. Distribution map of Blakea cubarralensis and related species. Red dots: B. cubarralensis; Black dots: B. latifolia; Green triangles: B. truncata. Map by Carlos Paz.