Miconia lorenaensis J.S.Murillo

Murillo-Serna, Jhon S., Londoño-Echeverri, Yeison & David-Higuita, Heriberto, 2021, Miconia lorenaensis (Melastomataceae), a new species from Colombian Andes, Phytotaxa 501 (1), pp. 162-170 : 166-168

Miconia lorenaensis J.S.Murillo , Londono-E. & H.David, sp. nov.

Type:— COLOMBIA. Tolima: Municipio de El Chaparral, vereda Aurora-Hermosas, finca La Lorena , inmediaciones del PNN Las Hermosas-Gloria Valencia de Castaño , 3°49’51.78’’N, 75°44’27.67’’W, 2500 m, 6 August 2018, (fl.), M. Jiménez & N. Castro 1 (holotype: FAUC-30073; isotype: HUA!). Figures 1 , 2 , 3 .

Diagnosis:— A species of Miconia sect. Amblyarrhena that can be distinguished by the combination of branches, petioles and leaves covered by scattered short dendritic trichomes; 7-nerved peltate leaves, acuminate or cuspidate apex with a circinate-thickened tip and flowers with 3-locular ovary, completely inferior. Miconia lorenaensis is similar to Miconia clypeata Wurdack (1982: 302) but differs by its branches sulcate-quadrangular with nodes without stipuliform-flaps (vs. winged-quadrangular and nodes with conspicuous stipuliform-flaps in M. clypeata ), and peltate leaves without scutum in the base of blade (vs. leaves with marginal petioles with a conspicuous scutum in the blade’s petiole insertion point).

Tree 4–6 m tall. Branches, vegetative buds and petioles covered with short dendritic trichomes ca. 0.05 mm diam. Internodes 4.2–6.2 cm long, 1.6–3.3 mm diam., sulcate-quadrangular. Leaves peltate, slightly unequal at the same node, the smaller ones 63.6–90.5 % as long as ther larger ones, papyraceous, acrodromous, 3 pairs of secondary veins (including the marginal pair), slightly plinerved, impressed on adaxial surface, raised on abaxial surface; larger leaves with the petiole attached 4.5–15.5 mm from the basal edge, petioles 3.3–13.1 cm long, 1.3–2.7 mm diam., terete and grooved; leaf blades 12.6–22.5 × 8.6–17.5 cm, L/W ratio 1.2–1.5, elliptic (-suborbicular), base rounded or subcordate, apex acuminate to cuspidate, the tip thickened and circinate, margin entire; 26–32 tertiary veins adjacent to the middle vein, 1.2–8.6 mm apart; smaller leaves, with the petiole attached 3–8.9 mm from the basal edge, petioles 2.8–6.8 cm long, 1–2.3 mm diam., terete and grooved; leaf blades 8.2–15.4 × 5.5–11.5 cm, L/W ratio, general shape, apex, base and margin as in the bigger leaves, with 24–30 tertiary veins adjacent to the middle vein, 1–7.3 mm apart; adaxial surface of both type of leaves covered with scattered, caducous, sessile, short dendritic trichomes and abaxial surface moderately covered with same indumentum as adaxial surface, more dense on the nerves and proximal and distal regions. Inflorescence a terminal panicle, 13–33 cm long, pyramidal, multiflorous; axes covered with sessile, short dendritic trichomes; peduncle 3.2–7.3 cm long, rachis with 5–6 internodes, first internode 3.9–8.3 cm long, first paracladia 4–18 cm long; proximal bracts foliose (as the leaves, but shorter), petioles 2–9 cm long, 0.9–1.7 mm diam., leaf blades 4.8–15.7 × 2.5–13.9 cm; bracteoles not seen. Flowers 5-merous, pedicel 0.5–0.9 mm long, 0.9–1 mm diam. Hypanthium 3–3.7 mm long up to the torus, 3.2–3.5 mm diam. at the torus, cupuliform, dull-green to whitish, internally glabrous, externally covered with scattered, sessile and short dendritic trichomes. Calyx open in bud, persistent in fruit, internally glabrous, externally with trichomes similar to the ones on the hypanthium; tube 0.9–1.1 mm long; calyx lobes 0.6–0.9 mm long, membranous, slightly undulate-lobed, hyaline; outer calyx teeth marginal, deltoid, 0.3–0.4 × 0.3–0.4 mm. Petals white at anthesis, 3–3.8 × 2.4–3.2 mm, asymmetrical, obovate, orbicular or elliptical, apex truncate, rounded or obtuse, margin entire to irregularly sinuate, glabrous, reflexed at anthesis. Stamens 10, isomorphic, actinomorphic; filaments white, glabrous, 2.9–3.3 mm long, 0.7–0.9 mm wide in dorsal position, 0.3–0.6 mm wide in lateral position; anthers with 2 locules, thecae yellow at anthesis, 2.1–2.3 mm long, 0.6–1 mm diam., cuneate, slightly tapering apically, opening by 1 dorsally inclined pore, 0.1 mm diam, connective not extended below thecae. Ovary 3- locular, completely inferior, apex with sparsely glandular trichomes, without a corona, 1.3–1.9 mm long, 1.9–2.2 mm diam. in longitudinal section, hypanthium diameter in the middle of the locules 2.7–3.1 mm; style 7.5–8.7 mm long, base 0.4–0.5 mm diam, slightly arcuate, glabrous; stigma punctiform, 0.5–0.7 mm wide. Berries green when immature (mature not seen), 3.5–4.3 × 3.4–3.7 mm, globose and crowned by the remaining calyx; seeds not seen.

Distribution and habitat:— Miconia lorenaensis is endemic to the Cordillera Central of the Colombian Andes, where it has been collected only at the department of Tolima, on El Chaparral municipality, at an elevation close to 2500 m ( Fig. 3 ). It grows in the understory of riparian forests, in lower montane wet forests.

Phenology: — Collected with flowers in August and with immature fruits in September.

Conservation status:— Miconia lorenaensis is known only from its type locality. The only population known grows in the vicinity of Las Hermosas-Gloria Valencia de Castaño National Natural Park (figure 3), but outside of the protected area. Based on the small area of occupancy (<10 km 2), few number of locations (= 1), and the decrease in habitat quality due to forest clearing, in addition to being less than 25 km from oil concessions, less than 15 km from a populated center and less than 1 km from the agricultural border, we suggest the “Critically Endangered” (CR) category, following the IUCN guidelines and criteria B2ab(iii) ( IUCN 2012, 2019).

Etymology:— The epithet lorenaensis makes reference to the name of the property “ La Lorena” which is in the registration process as a private protected area. This is the type locality of the new species.

Additional specimen examined (paratype): — COLOMBIA. Tolima: Municipio de Chaparral: vereda Aurora- Hermosas, finca La Lorena , inmediaciones del PNN Las Hermosas-Gloria Valencia de Castaño , 3°49ʹ51.78ʹʹN, 75°44ʹ27.67ʹʹW, 2500 m, 5 Sep 2018 (im. fr.), Y. Londoño & C. Portela 457 (FAUC!) .

Miconia lorenaensis belongs to Miconia sect. Amblyarrhena because of its stamens with short, stout anthers with a slightly tapering apex, opening by a small terminal pore. Among the species in this alliance, Miconia lorenaensis is morphologically similar to Miconia clypeata and Miconia perobscura Wurdack (1961: 42–43) ; Miconia lorenaensis has branches, petioles, leaf blades and flowers covered by scattered short dendritic trichomes; the leaf blades are peltate, with an acuminate or cuspidate apex and a circinate-thickened tip; its flowers have a completely inferior ovary. In contrast, the indumentum of M. clypeata has stellate-lepidote and dendroid hairs, the petioles have a marginal insertion point, the leaves have a scutum in the base of the blade (not present in M. lorenaensis ), and the flowers have a ½ inferior ovary ( Wurdack 1982). Miconia perobscura has 7-markedly plinerved leaves (not peltate) and indumentum with stellate, briefly stipitate hairs in vegetative parts, and stellate-puberulous trichomes in flowers ( Wurdack 1961); in addition to that, this species is endemic to Venezuela ( Goldenberg et al. 2013).

Miconia lorenaensis is also similar to Miconia peltata Almeda (1989: 217) in having peltate leaves with rounded or subcordate leaf blades, but this species is densely covered with rusty-brown, pinoid hairs on axes and leaves and it has flowers with a 5-locular, ⅔ inferior ovary ( Almeda 1989); in addition to that, Goldenberg et al. (2013) report this species as endemic to Panama and includes M. peltata in Miconia sect. Miconia Candolle (1828: 183) . Nevertheless, this species has been found to be part of the Conostegia clade ( Kriebel et al. 2015) and was studied in detail in the Kriebel’s monograph under the name Conostegia peltata ( Almeda 1989: 217) Kriebel (2016: 281) .

See Table 1 for distinguishing characters and distribution among these four species.

Figures

FIGURE 1. Miconia lorenaensis. A. Fertile branch.B. Young leaves. C. Petiole insertion.D. Hypanthium. E. Hypanthium in longitudinal section. F. Stamen in dorsal, lateral and ventral views. Illustration by Ana Pareja, based on Jiménez & Castro 1.

FIGURE 2. Miconia lorenaensis and its habitat. A. Habitat of M. lorenaensis. B. Fertile branch. C. Leaf apex, adaxial surface. D. Leaf base, adaxial surface. E. Inflorescence cyme, central flower in anthesis and laterals in buds. F. Immature fruits. Photographs A–B, F: Yeison Londoño (HUA), C–E: Carlos Morales (WCS Colombia).

FIGURE 3. Distribution map of Miconia lorenaensis.