Meliosma primogenita D. Ruiz-Mol. & F. Ávila, 2024

Molina, Daniel Ruiz, Ávila, Fabio A. & Cortés-B, Rocío, 2024, Two new species of Meliosma (Sabiaceae) from the Eastern Cordillera in Colombia, Phytotaxa 666 (2), pp. 107-120 : 109-114

Meliosma primogenita D. Ruiz-Mol. & F. Ávila , sp. nov. ( Figs. 1–3 )

urn:lsid:ipni.org:names:77348347-1

Type: — COLOMBIA. Cundinamarca: Mun. San Antonio del Tequendama, Parque Natural Chicaque, sendero hacia la cascada, 4°36’53.3”N, 74°18’40.5”W, 2000 m, 11 April 2022, D. Ruiz M 561 (holotype: 048267!, 047420!, 047421! UDBC-3 sheets).

Diagnosis: — Meliosma primogenita was traditionally confused with Meliosma bogotana Steyermark (1953: 500) but differs by being puberulous on the petioles, veins, abaxial surface, and inflorescences and by having glandular trichomes on these structures (vs. densely pilose on the same structures). The petioles of M. primogenita are longer (7–10 vs. 3–5 cm), and its inflorescences are erect, terminal, or axillary up to 50 cm long (vs. pendulous and usually ramiflorous inflorescences up to 1 m long). The outer and inner petals of M. primogenita are reclined at anthesis (vs. porrect at anthesis), and the connective tissue of the stamens extends beyond the thecae (vs. ending at the level of the thecae).

Trees up to 25 m tall and 1 m DBH with a defined main trunk or shrublike trees up to 5 m tall branched from the base and 5 cm DBH. Terminal branchlets terete or slightly angled, 8–13 mm diameter, puberulous with simple, short (<0.5 mm long) and erect trichomes and with sessile or stipitate-glandular trichomes (<0.5 mm), mature branches eventually glabrescent. Terminal buds are densely pilose with long (0.5–1 mm) simple curved trichomes. Leaves alternate; petioles terete, (5–) 6–10 (–13) cm long × 3–5 mm diameter, puberulous and with glandular trichomes, pulvinus inconspicuous after drying; blade (15–) 20–55 (–70) × (6–) 12–19 (–21) cm, oblanceolate to elliptic, chartaceous, base acute, margin entire or serrate in the distal half in young individuals, apex acute, convex to rounded; venation pinnate, eucamptodromous to brochidodromous, with 14–22 secondary veins per side with a regular spacing of 1–2 cm, intersecondary veins less than half the length of adjacent secondary veins, every one or two intercostal spaces, tertiary veins with mixed percurrent pattern, epimedial veins less than 1 per intercostal space; adaxial surface with sessile and stipitate-glandular trichomes, eventually glabrescent, midvein immersed, puberulous and with sessile and stipitate-glandular trichomes, secondary veins flat; abaxial surface with sessile and stipitate-glandular trichomes, eventually glabrescent, midvein prominent, puberulous with short and erect trichomes and with sessile or stipitate-glandular trichomes, secondary veins prominent, puberulous and with scattered glandular trichomes, tertiary veins prominulous with scarce and scattered glandular trichomes. Inflorescence an erect terminal panicle up to 50 cm long, 1 cm diameter at the proximal portion, secondary axes up to 18 cm long, three times branched, axes khaki, ferruginous to russet (when fresh), puberulous and with sessile and stipitate-glandular trichomes; bracts 1–2.5 mm long, cymbiform with acute apex, puberulous and with glandular trichomes on the dorsal surface, bracteoles 0.3–0.5 × 0.3–0.5 mm suborbicular, obtuse to rounded apex, puberulous and with glandular trichomes on the dorsal surface and ciliate margin. Flowers sessile or pedicels up to 0.2 mm; sepals 5, suborbicular to ovate, 0.8–1.2 × 0.8–1 mm, margin ciliate, glandular and erect trichomes on the dorsal surface; outer petals 3, 2–2.5 × 1.8–2.5 mm, same sized or the two lateral narrower than the central, suborbicular to broadly ovate, rounded, patent to reclined in anthesis, pink externally and pale pink internally (when fresh), glabrous; inner petals 2, 1.8–2.3 × 0.6–0.8 mm, longer than the stamens, oblong to oblong-elliptic, rounded to convex apex, reclined in anthesis, white (when fresh); stamens 2, 1.5–2 mm, connective tissue broadly elliptic, rounded apex and apically extended beyond the thecae; staminodes 3, 0.5–0.8 × 0.6–0.9 mm; ovary 0.7–0.9 × 0.7–0.9 mm, bilocular, ovoid and glabrous; style 0.2–0.4 mm, stigma truncated and slightly divided. Infructescence axes are puberulous, with glandular trichomes and glabrescent and grayish when mature. Fruits oblique to the axis, pyriform to obovoid when mature and pyriform to suborbicular when immature, 1.6–2 × 1.4–1.5 cm; endocarp pyriform to suborbicular constrained towards an extended base 1.2–1.5 × 1.2–1.4 × 1–1.2 cm, pyrene surface slightly rough and rugose.

Distribution and habitat: — Meliosma primogenita is an endemic species to the Colombian Andes that has been collected in Andean forest remnants at 1900–2700 elevation m in the Boyacá and Cundinamarca departments, located on the Eastern Cordillera, and in the Quindío and Risaralda departments, located on the Central Cordillera ( Fig. 4 ). In Cundinamarca and Boyacá, it has been found growing with populations of Quercus humboldtii Bonpland in Humboldt (1809:155). Its presence is also presumed in the Western Cordillera; however, collections cannot confirm it.

Phenology: —It flowers between April and September and fruits between December and March.

Etymology: —The specific epithet primogenita comes from the Latin “ primogenitus ”, which means firstborn son or first child. It refers to the first author’s firstborn child, to whom this new species is dedicated as a celebration and the profound joy of new parenthood.

Conservation status: —The Andean forest, the natural habitat of Meliosma primogenita , has been severely affected and shows one of the highest rates of degradation and change compared to other ecosystems in the country due to anthropic activity primarily driven by ongoing agricultural expansion and livestock farming ( Correa et al. 2020). The reduction of this ecosystem’s area has been pointed out by different authors for several decades ( Etter & Wyngaarden 2000, Tovar et al. 2022). This situation is even more critical considering the relationship of M. primogenita with oak forests (dominated by Quercus humboldtii ), which are even scarcer in Colombia and are present in the Andean forest areas ( Avella & Cárdenas 2010). However, a population of M. primogenita has been found within Chicaque Natural Park, a local protected area that conserves approximately 300 hectares of Andean cloud forest. Several collections, including the type specimen, were collected in this locality. The presence of this species in a protected area provides an opportunity to establish population studies, propagation experiments, and other research that could contribute to its future conservation. This finding is particularly significant given the restricted distribution known so far and the ongoing threats to its habitat. With an Area of Occupancy (AOO) of 32 km 2 between the eastern and central cordilleras, the existence of only seven subpopulations (r = 5 km) corresponding to seven localities, and the continued decrease in its area and habitat, it is proposed to include M. primogenita in the “Endangered” (EN) category of the IUCN according to criteria B2b(ii,iii) related to the AOO of this species.

Discussion: —Vegetatively Meliosma primogenita is similar to M. bogotana from Colombian eastern Cordillera, M. condorensis Cornejo (2008: 96) from Ecuador, M. novogranatensis Cuatrecasas & Idrobo (1955: 196) from Colombian western Cordillera and M. pittieriana Steyermark (1952: 354) from Colombian eastern Cordillera, mainly because of the large leaves (more than 20 cm long), the oblanceolate, obovate or oblong-elliptic leaf shape, and long petioles (more than 5 cm). However, it can be differentiated from each one by the following characters:

In addition to the morphological differences with Meliosma bogotana presented in the diagnosis, field observations suggest a frequent overlap in the habitat ranges of these two species. This geographic pattern has contributed to misidentifying them. However, with the diagnosis presented, the differentiation between these two species is now clear, even when sterile specimens.

Meliosma condorensis is densely pilose on the veins, petioles, young branches, and inflorescence (vs. puberulous and with glandular trichomes on these structures). The petioles are shorter (4–6 vs. 7–10 cm), and the blades have a truncate to rounded apex (vs. acute to convex). The flowers have longer pedicels (0.5–1.5 vs. 0.2 mm), inner petals with bifid apex and shorter than the stamens (vs. inner petals with a rounded apex and longer than the stamens), longer styles (0.3–0.6 vs. 0.2–0.4 mm) and the flowers scattered in the inflorescence (vs. clustered on the axes). Additionally, this species has only been found in the Cordillera del Cóndor in Ecuador.

Meliosma novogranatensis has glabrous leaves and petioles and scarcely puberulous inflorescences (vs. leaves, petioles, and inflorescences puberulous and with glandular trichomes), shorter petioles (4–6 vs. 7–10 cm) and obtuse to rounded leaf bases (vs. acute base). The flowers are scattered on the axes (vs. clustered on the axes), have longer pedicels (1 vs. 0.2 mm), and the inner petals are equal or shorter than the stamens (vs. inner petals longer than the stamens).

Meliosma pittieriana is densely pilose, with appressed and curved trichomes on its young branches, petioles, abaxial leaf surface, veins, and inflorescence axes (vs. puberulous and with glandular trichomes on these structures). Leaves have rounded apex (vs. acute to convex apex) and fewer secondary veins per side (11–16 vs. 14–22). Also, the density of the number of flowers in the inflorescence is loose (vs. compact).

Additional specimens examined (paratypes): — COLOMBIA. Boyacá: a 10 km del páramo de la Rusia, 2900 m, sf. (fl.) H. Mendoza 3901 (JAUM 052008!). Mun. Duitama, Corr. Santa Helena , 1856 m, 12 October 2007 (fr), M. Reina, W. Ariza, O. Chaparro 5 (UDBC 25762!, 26375!, 26378!) . Cundinamarca: Mun. Granada, Carretera a Fusagasugá entre Granada y Silvania , 2000 m, 16 June 1964 (fl), H. García-B. 18055 (COL 115593!) ; Mun. Pacho, 1965 (fl), G. Mahecha s.n. (UDBC 5308!), 1965 (fl), G. Mahecha s.n. (UDBC 5312!), 1965, G. Mahecha s.n. (UDBC 5349!), 1965, G. Mahecha s.n. (UDBC 5366!), 1965 (fl), G. Mahecha s.n. (UDBC 5380!), 1967 (fl), G. Mahecha s.n. (UDBC 5145!), 1965 (fl), G. Mahecha 151 (UDBC 5344!); Vda. El Hatillo, Finca de Benedita Mahecha , 2000 m, 01 September 1970 (fl), G. Mahecha 1600 (COL 151467!) ; Vda. El Pinal, Reserva El Nacedero , 2300 m, 25 January 2023 (fr), D. Ruiz, F. Ruiz & C. Tapiero 330 (UDBC 48284!, JBB!) ; Vda. La Esmeralda , 1900 m, 16 November 1969 (fr), G. Mahecha s.n. (UDBC 4909!) ; Mun. San Antonio del Tequendama, Parque Natural Chicaque , 2000 m, 11 July 2020 (fl), D. Ruiz 171 ( COL!), ibid. 23 October 2022 (fl), D. Ruiz 428 ( FMB!), ibid. 05 July 2023 (fl) C. Mora 22 ( UIS!), ibid. 05 July 2023 (fl) C. Mora 23 ( JBB!) . Quindío: Mun. Córdoba, Vda. Carniceros, Finca La Argentina , Carretera Córdoba-Pijao , 1800 m, 23 March 1990 (fl), M. Vélez et al. 1229 (COL 334360!) . Risaralda: Mun. Santa Rosa, Camino de Herradura entre Termales y el Páramo de Santa Rosa, 2600 m, 17 July 1980 (fl), J. Idrobo et al. 9548 (COL 270196!). Without locality: s.n. (fl) Mutis 4348 ( US 1561679!).

Figures

FIGURE 1. Meliosma primogenita D. Ruiz-Mol. & F. Ávila. A. Floral terminal branch.B. Adaxial leaf surface.C.Abaxial leaf surface. D. Upper view of the calyx. Nectariferous disk and its appendages at the center. E. Sepal with puberulous indument and glandular trichomes. F. Mature flower without outer petals showing the relative position of inner petals. G. Left outer petal with adnate staminode. H. Right outer petal with adnate staminode. I. Inner petal. J. Dorsal view of stamen. K. Ventral view of stamen. Scale bar = 1 mm. (A. from D. Ruiz 171; B–K from holotype; Illustration by Omar Bernal).

FIGURE 2. Meliosma primogenita D. Ruiz-Mol. & F. Ávila. A. Floral terminal branch and detail of flowers on a terminal axis. B. Isolated infructescence. C. Abaxial surface detail and zoom on the margin, arrows indicating glandular trichomes. D. Mature flower showing the relative position of inner petals. E. Ovary. F. Three outer petals with adnate staminodes. G. Dorsal and ventral view of stamens. H. Inner petal. I. Sepal. J. Fruit. (A, C–I from the holotype; B, J from M. Reina et al. 5).

FIGURE 3. Meliosma primogenita D. Ruiz-Mol. & F. Ávila. A. Fertile terminal branch. B. Detail of abaxial blade surface. C. Flowers on a terminal axis: yellow arrows pointing to stamens, pink arrows pointing to outer petals, white arrows pointing to inner petals, green arrow pointing to staminodes surrounding ovary. (A–C from the holotype; Photos:A–B by Daniel Ruiz; C by Geraldine Moreno).

FIGURE 4. Distribution map of Meliosma primogenita and Meliosma quercifolia.