Begonia comata Kuntze

Moonlight, Peter & Fuentes, Alfredo F., 2022, AN UPDATED CHECKLIST AND KEY TO THE SPECIES OF BOLIVIAN BEGONIA, INCLUDING ONE NEW SPECIES, Edinburgh Journal of Botany 79 (407), pp. 1-66 : 47-49

8.36. Begonia comata Kuntze , Revis. Gen. Pl. 3(3): 105 (1898).

– Type: Bolivia, [Cochabamba

Department], Tunari, [17°3′S, 66°43′W], 1800 m, iv 1892, C.E.O. Kuntze s.n. (lectotype NY [ NY00118604 ] designated here first stage designated in: Revista Univ. ( Cuzco ) 33(87): 83 (1944) by Smith, L.B. & Schubert, B.G.; isolectotypes B [ B100366049 ], NY [ NY00118603 ] ); ibid., 2300 m, iv-v 1892, C.E.O. Kuntze s.n. (syntype US [ US00115287 ]) .

L.B. Smith & B.G. Schubert, Revista Univ. (Cuzco) 33(87): 83 (1944); R.C. Foster, Contr. Gray Herb. 184: 137 (1958); D.C. Wasshausen et al. in P.M. JØrgensen et al. (eds), Cat. Bolivia, Monogr. Syst. Bot. Missouri Bot. Gard. 129: 384 (2013).

Caulescent herb, to 70 cm tall. Stem erect, rarely branching; internodes to 4.5 cm long, to 10.5 mm thick, succulent, green, glabrous. Stipules persistent, lanceolate, 8–27 × 3–10 mm, apex rounded, translucent, brown, glabrous, margin lacerate, long-ciliate. Leaves> 5 per stem, alternate, basifixed; petiole 0.3–2.2 cm long, red, glabrous; blade asymmetrical, lanceolate, to 9.5 × 3 cm, membranaceous, apex acuminate, base auriculate on the broader side, the basal lobe usually overlapping the petiole, cuneate on the narrower side, margin serrulate, ciliate, upper surface green, glabrous, lower surface pale green with red spots, glabrous, veins palmate-pinnate, secondary veins indistinct. Inflorescences> 3 per stem, either unisexual or bisexual and strongly protandrous, axillary, erect, cymose, with 2 or 3 branches, bearing up to 8 staminate flowers and/or 8 pistillate flowers; peduncle to 6.5 cm long, red, glabrous, bracts deciduous, broadly ovate, 4–6.5 × 4–7 mm, colour unknown, glabrous, apex acute, margin serrulate, long-ciliate. Staminate flowers: pedicels to 15.5 mm long, glabrous; tepals 2, spreading, ovate broadly ovate, 10–16 × 10–17 mm, apex obtuse to rounded, base cordate to rounded, red, glabrous, margin entire, aciliate; stamens c.12, projecting, yellow, filaments 0.75 mm long, free, anthers linear, 1–1.5 × 0.2 mm, dehiscing via lateral slits, connectives not extended, symmetrically basifixed. Pistillate flowers: pedicels to 10 mm long; bracteoles 3, positioned directly beneath the ovary, ovate, 10–13 × 6–7.5 mm, apex acute, red, glabrous, margin serrulate, ciliate; tepals 5, subequal, late deciduous in fruit, spreading, ovate, 8–10 × 5–9 mm, apex obtuse, red, glabrous, margin entire, aciliate; ovary body ovoid, 3–5 × 2.5–4 mm, red, glabrous, unequally 3-winged, wings semicircular, largest c.6 × 3 mm, smallest c.6 × 2 mm; 3-locular, placentation axillary, branches divided, bearing ovules between the placental branches; styles 3, yellow, free, 1.5–2.5 mm long, bifid, stigmatic papillae in a spirally twisted band. Fruiting pedicel to

14 mm long. Fruit a capsule, body ovate, to 8 × 9.5 mm, drying brown, wings same shape as in ovary, the largest expanding to 12 × 20.5 mm, the smallest expanding to 12 × 5 mm.

Distribution and ecology. Endemic to Bolivia and known from La Paz and Cochabamba Departments. It is typically collected around rocks in semideciduous montane forests at an elevation of 980–1800 m. Begonia comata has been collected in flower and fruit from April to December.

Etymology. The epithet derives from the Latin word comatus, meaning ‘long-haired’. This refers to the species’ long-ciliate stipule margins.

Proposed IUCN conservation category. Begonia comata is known from a narrow elevational band and has an EOO of c. 5500 km 2. This area includes a large percentage of original forest cover and the species has population known from the Area Natural de Manejo Integrado Apolobamba. However, the species has been rarely collected and appears to have a patchy distribution. We assess Begonia comata as Vulnerable (VU), B1abiii, under IUCN criteria ( IUCN Standards and Petitions Subcommittee, 2019).

Additional specimens examined. BOLIVIA. La Paz Department. Bautista Saavedra Province: Area Natural de Manejo Integrado Apolobamba, c. del cruce para subir a Camata por la carretera a Charazani , 15 ° 12′59′′S, 68 ° 41′3′′W, 1290 m, 3 ix 2004, A. Fuentes & C. Aldana 6690 ( LPB, MO) . Sud Yungas Province: Chulumani, 52 km hacia Asunta , [16 ° 12′S, 67 ° 12′W], 980 m, 8 viii 1983, S. G. Beck 8596 ( LPB, MO) ; Bajada de Chulumani a Asunta, comunidad de Zona Esperanza, mas abajo de villa Barrientos , 16 ° 17.69′S, 67 ° 23.78′W, 1009 m, 2 iv 2004, J. R. I. Wood, M. Atahuachi & M. Mendoza 20611 ( K) . Inquisivi Province: “Puente Alegre”, the area where the Cajuata-Siquimirani road crosses the río Suri , 1 km SE of Cajuata, 16 ° 43′S, 67 ° 10′W, 1500 m, 28 xii 1989, M. Lewis 36911 ( LPB, MO) .

Notes. Begonia comata is most similar and, we believe, most closely related to Begonia oblanceolata (see Identification notes). These two species were treated in Begonia sect. Warburgina and Begonia sect. Ruizopavonia , respectively, in the latest two sectional classifications of Begonia ( Doorenbos et al., 1998; Moonlight et al., 2018). Begonia comata was the only species in Begonia sect. Warburgina in both classifications, and this section was maintained as separate from Begonia sect. Ruizopavonia on account of Begonia comata ’s four tepals in the pistillate flower and having a unisexual inflorescence. The original description of Begonia comata cites four tepals in the pistillate flowers, but an isotype held in New York (NY00118603) has a dissected pistillate flower that clearly shows five tepals. A second isotype held in Berlin (B100366049) is less clear but also appears to show five tepals on the pistillate flower.

Kuntze also described Begonia comata as having a unisexual inflorescence. All known inflorescences of this species have either staminate or pistillate flowers, which is consistent with this theory. However, all staminate flowers are on relatively small inflorescences, which appear young. In contrast, all known pistillate flowers and fruits are held towards the apex of larger, more developed inflorescences that appear old and have scars that may represent the former position of staminate flowers. We believe it is more likely that the inflorescences of Begonia comata are strongly protandrous rather than unisexual, perhaps with no temporal overlap between the staminate and pistillate flowers. The inflorescences of Begonia oblanceolata are similar but have always been treated as bisexual in the literature. Because no unambiguous characters remain to separate Begonia sect. Warburgina from Begonia sect. Ruizopavonia , we transfer B. comata into Begonia sect. Ruizopavonia and treat Begonia sect. Warburgina as a synonym of Begonia sect. Ruizopavonia .

Nomenclatural notes. Otto Kuntze cited material collected in Tunari, Bolivia, from 1800 to 2300 m elevation in the protologue of Begonia comata . This citation matches what appears to be two separate collections made by Kuntze: one from 1800 m and a second from

2300 m. Smith & Schubert (1944a) cited material collected from 1800 to 2300 m and held in the New York Botanical Garden herbarium as the type, which is a first-stage lectotypification. We designate the sheet NY00118604 as the lectotype because it is the only sheet in New York where the flowers remain attached to the vegetative material.

Identification notes. Distinguished as a glabrous herb with persistent stipules with long-ciliate margins, lanceolate leaves with palmate-pinnate venation, and bifid styles. Begonia comata is most similar to B. oblanceolata . The two have a similar habit, with upright, rarely branching stems reaching around a metre in height. They both also have persistent stipules with long-ciliate margins, few-flowered inflorescences with persistent bracts, staminate flowers with two tepals, and pistillate flowers with five tepals. They are also unique within Bolivian Begonia sect. Ruizopavonia in having glabrous, lanceolate to oblanceolate leaves with palmate-pinnate venation and indistinct, strongly camptodromous secondary venation. The two species differ in the number of bracteoles in the pistillate flower ( Begonia comata has three and B. oblanceolata has one), the shape of their fruit body (ovoid in B. comata , obdeltoid in B. oblanceolata ) and wings (semicircular in B. comata , triangular and ascending in B. oblanceolata ), and their styles (bifid in B. comata , multifid in B. oblanceolata ). When sterile, the two species are best distinguished by their leaf bases. Both species have cuneate leaf bases on the narrower side of the leaf but the base of the broader side of the leaf is rounded in Begonia oblanceolata and auriculate, often overlapping the petiole in B. comata .