Monteverdia zakii Biral & Cornejo, 2021

Biral, Leonardo & Cornejo, Xavier, 2021, Two new species of Monteverdia (Celastraceae) from Ecuador, Phytotaxa 479 (2), pp. 183-190 : 186-189

Monteverdia zakii Biral & Cornejo , sp. nov. ( Figs. 3 and 4 )

Type:— ECUADOR. Pichincha: road Chiriboga - Santo Domingo, just below Chiriboga , 00º17’S, 78º46’W, 1900 m, 2 June 1979, Holm- Nielsen 18117 (holotype NY; isotypes AAU, MO, S) .

Affinis Monteverdia macrocarpa (Ruiz & Pav.) Biral foliis oblongis, inflorescentiae fasciculatae et fructibus grandibus, sed ramis lenticellatis, foliis coriaceis, nervis secundatis inconspicuis et fructibus magnis (18–27 x 12–23 vs 13–27 x 11–15 mm) cum basi truncata differ.

Tree or shrub, 4–14 m tall, with a slender trunk, glabrous; old twigs cylindrical, blackened (dry), densely lenticellate, lenticels prominent; young twigs flattened, longitudinally ribbed, grayish (dry), without lenticels. Leaves alternate, distichous; stipules 1 mm long, deltoid, base truncate, apex acute, caducous; petiole 5–15 mm long, cylindrical; blades 14.4–21.3 × 5.4–8.6 cm, oblong-elliptic, coriaceous, base cuneate, margin entire or slightly crenate on distal portion, revolute on proximal portion, apex acuminate, glabrous, drying reddish brown on both faces; venation brochidodromous, primary vein plane on the adaxial face, plane on the abaxial face, secondary veins 7–9 pairs, more or less ascendant, 50º to 40º from midvein, obscure on both faces or rare smoothly impressed on abaxial face. Inflorescences fasciculate, simple, axillary, multi or pauci-flowered; pedicels 4–10 mm long, cylindrical. Flowers 5-merous, green, prefloration imbricate, in one row with the margins of one petal overlapping two other petals, three petals with one margin external and the other internal, and one petal with both margins completely internal; calyx gamosepalous at base, lobes 1 × 1 mm, brownish, ovate, margin sparsely ciliate; corolla dialypetalous, petals 2–3 × 1 mm, green, oblong, patent at anthesis, apex rounded, margin membranous, hyaline, slightly undulate; stamens 5, alternate with petals, 2 mm long, filaments flattened, broadened at base, attenuated at apex, inserted on the margin of disk, erect and becoming reflexive at anthesis; anthers ovoid, yellow, dorsifixed, dehiscing longitudinally; disk intrastaminal, 2 mm in diam., pentagonal, blackened when dry, margin slightly undulate; gynoecium 2-carpellate, ovary superior, fused to disk, style evident, stigma simple. Fruit a loculicidal capsule, 18–27 × 11–23 mm, obovoid or spherical, peduncle rugose, base truncate, apex rounded, style not persisting, red when ripe, black externally when dry, brown with white stains internally, opening by 2 valves; seeds 1–2, 1.3–1.8 × 1–1.3 mm, ellipsoid, smooth, completely surrounded by white aril, maturing brown to black, glossy when dry.

Phenology. Flowering in July and September; fruiting in June and September.

Etymology. The epithet of the new species honors Vlastimil Zak, an Ecuadorian biologist and prolific collector of plants, and former curator of USFQ herbarium in Quito. Zak and Jaime Jaramillo (former QCA curator and a celebrated professor of botany at Pontifical Catholic University), co-owned the Rio Guajalito Reserve in which the new species occurs. Zak, who worked so hard for the conservation of the Reserve, recently passed away due to the COVID-19 virus that has been so devastating in Ecuador.

Distribution and habitat. Monteverdia zakii is apparently restricted to the west side of Montane Andean forests, particularly in Pichincha province, between 1800–2250 m in elevation.

Vernacular name: Unknown.

Biological interactions and uses. Unknown.

Conservation status. The conservation status of Endangered is recommended for Monteverdia zakii , based on the IUCN (2012) criteria ( EN B 1ab[iii]). Ongoing deforestation in northwestern Ecuador is leading to fragmentation and degradation of habitat with small forest patches becoming extinct. As yet, M. zakii has not been recorded within the National System of Protected Areas of the country ( PANE).

Notes. Due to the low variability of reproductive characters, especially within large Celastraceae genera [e.g., Monteverdia and Gymnosporia ( Wight & Arnott 1834: 159) Hooker f. in Bentham & Hooker f. (1862: 359, 365)], vegetative characters, such as leaves, are important to use in species characterization. Monteverdia zakii closely resembles M. macrocarpa (Ruiz & Pav. 1802: 8) Biral in Biral et al. (2017: 689), with which it shares oblong to elliptic leaves, fasciculate inflorescence and obovoid to spherical fruits. As such, specimens of M. zakii are commonly found in herbaria determined as Maytenus / Monteverdia macrocarpa . However despite these similarities, M. zakii can be differentiated from M. macrocarpa by the unique combination of: lenticels on twigs (vs absent/rare), coriaceous leaves with obscure secondary veins (vs chartaceous and visible veins, especially on abaxial face), and usually larger fruits, 18–27 × 11–23 mm (vs 13–27 × 11–15 mm) with a truncate base (vs. a cuneate base). The leaves that usually dry reddish to brown (vs green) may also help in the identification of dehydrated specimens. The combination of cited characters makes its distinction possible from all other species.

Additional specimens examined (paratypes): ECUADOR. Pichincha: Reserva Florística-Ecológica “Rio Guajalito”, km 59 of the old road Quito-Sto. Domingo de los Colorados , 3.5 km to the northeastern of the road, western foothills of Pichincha volcano, 00º13’53’’S 78º48’10’’W, 31 August 1985, Zak & Jaramillo 594 ( G, INPA, MO, US) ; Ibidem , 20 July 1991, Jaramillo & Grijalva 13569 ( MO, NY) ; Parroquia Nanegalito, disturbed rain forest on steep slopes 5–6 km SE of Nanegalito, trail to Loma Pahuamba , 2250 m, 00º01.5’N 78º39’W, 2 September 1993, Webster et al. 30093 ( MBM, MO) ; Bosque Protector Maquipucuna, montane rain forest on steep slopes above Río Pichán , 7.5 km airline SE of Nanegalito, 1900–2000 m, 00º02.5’N 78º37’W, 1–2 September 1993, Webster & Castro 30232 ( MO, NY) .

Figures

FIGURE 3. Monteverdia zakii: A. Terminal branches bearing leaves and fruits. B. Two pedicellate mature fruits with truncate bases. C.A naked seed, the aril removed.A–C, from AAU isotype, courtesy of Birgitte Bergmann.

FIGURE 4. Monteverdia zakii: A. Branch. B. Ripe fruits. C. Internal view of a valve. A, C, from AAU isotype. B, from NY holotype. Drawings by André Moura Pedroso.