Begonia fritschiana Amoroso & Rubite, 2023

Amoroso, Victor B., Lamparas, Rica Joy V., Lagunday, Noel E., Dapar, Mark Llyod G. & Rubite, Rosario R., 2023, Begonia fritschiana (Begoniaceae, Begonia section Baryandra), a new species from Quezon, Bukidnon, Philippines, Phytotaxa 587 (1), pp. 39-46 : 42-44

Begonia fritschiana Amoroso & Rubite , sp. nov. § Baryandra ( Figs. 2–4 )

Type:— PHILIPPINES: Mindanao, Sto. Domingo, Quezon, Bukidnon, Mt. Pinamantawan , 1112–1130 m, on mossy rocks in shaded forest, 28 August 2022, V. B. Amoroso 31059 (holotype PNH!, isotype CMUH!) .

Diagnosis:— Begonia fritschiana resembles B. caramoanensis in having male flowers with 4 tepals and female flowers with 5 tepals, glandular hairy pedicels and peduncles, a capsule that is pendent, recurved with unequal wings, but differs by having leaves that are ovate (vs. almost orbicular), with a petiole that is 5–9 cm long (vs. 12–26 cm), and with the abaxial surface of the lamina glaucous with marginal hairs (vs. not glaucous and absent marginal hairs) solitary to singly-branched inflorescence (vs. dichotomously branched, 5 times), a peduncle and pedicels with white glandular hairs (vs. white to green and brown glandular hairs), one of the outer tepals dark pink abaxially (vs. uniformly pinkish), and a glabrous ovary (vs. with glandular hairs).

Herbaceous, lithophytic, rhizomatous, perennial, monoecious, creeping. Rhizome light green, sometimes covered with liverworts, ca. 3.5–5.4 cm × 0.4–0.5 cm, glabrous, internodes 5 mm long. Stipules persistent, symmetric, yellow turning dark brown when mature, ovate, 20–22 × 3–5 mm, abaxially with white hairs, margin entire with long distantly placed hairs, apex aristate, arista 4, up to 7 mm long. Leaves alternate, petiolate; petioles erect, yellowish-green, terete, with dense non-glandular hairs, becoming glabrous; lamina basifixed, thick and fleshy, obliquely ovate, 5–6 × 4–5 cm, adaxially dark green, abaxially glaucous, glabrous, base cordate, lobes not overlapping, margin subentire with white marginal hairs, apex mucronate, venation palmate-pinnate, primary veins 5–6, not prominent adaxially. Inflorescence axillary, arising directly from rhizome, mostly solitary and rarely branching singly, erect, 16–23 cm long, peduncle light green, 15–19 cm long, with dense white glandular hairs up to pedicels. Bracts caducous, usually sheathing developing buds, light green, broadly ovate, 4–8 × 4–5 mm, glabrous, margin entire, apex cuspidate. Staminate flower: actinomorphic, dark red when young, broadly ovate, pedicel 10–15 mm long, glandular-hairy, hairs white and profuse, tepals 2 + 2, one outer tepal dark pink abaxially and light pink adaxially, other tepals white, outer tepals orbicular, 9–11 × 6–9 mm, inner tepals narrowly lanceolate, 4–7 × 3–5 mm, stamens 14–21, filaments ca. 1 mm long, united at base, anthers yellow, obovate, apex rounded, ca. 1 mm long. Pistillate flower: ascending early then later recurving downward, pedicel white to light green, tepals 2 + 3, outer pair white, obovate, 10–12 × 7–8 mm, 3 inner tepals white, asymmetrical, 10–12 × 5–6 mm. Ovary inferior, green, 13 × 15 mm (wings included), 3-locular, glabrous, placentae bifid; wings 3, unequally surrounding ovary, light green; styles 2, 2–4 mm long, stigmas ca. 3 on each style, yellow. Fruiting pedicel 19–25 mm long, light green, glabrous to sparsely glandular-hairy, unequal. Capsule recurved, 13–15 × 10–15 mm (wings included), base rounded to cordate, apex obtuse, abaxial wing 10 × 8 mm, angular, lateral wings 7 × 5 mm, angular.

Phenology:—Observed flowering and fruiting in situ on August 28, 2022 and ex-situ on 2 September 2022 – 6 February 2023.

Etymology:—This species is named in honor of Dr. Peter W. Fritsch, renowned botanist from the Botanical Research Institute of Texas and Fort Worth Botanic Garden, USA, for discovering novel species and in his unwavering support for and participation on botanical exploration and research in the Philippines.

Distribution and Ecology:—Endemic to the province of Bukidnon, Mindanao, Philippines. It grows in a narrow elevation range at ca. 1100 m on boulders with a thin layer of soil with liverworts and Selaginella spp. in the lower montane forest of Mt. Pinamantawan, Quezon, Bukidnon. Some planted abaca ( Musa textilis ) were observed among the boulders.

Proposed Conservation Status:— Begonia fritschiana is known only from the type locality, with one population and less than 100 individuals. The area is not currently protected under the country’s National Integrated Protected Areas System by the Department of Environment and Natural Resources. Because of ongoing threats such as illegal logging, poaching, and over-collection of biological resources, the single area of occurrence with estimated extent of occurrence <10 km 2, and the small number of individuals observed, we recommend a classification of B. fritschiana as Critically Endangered CR based on the criterion B1ab(i) of IUCN (2022).

Comparison to other similar species:—The species shares having glandular hairs on the peduncles with B. droseriodes but B. fritschiana differs in having a light green creeping rhizome (vs. crimson); long arista on the stipule (4–7 mm) (vs. 2 mm); petioles up to 9 cm long with white non-glandular hairs (vs. petioles up to 12 cm long with dense pale brown appressed sericeous hairs); lamina margin with white hairs (vs. lamina margin with puberulous red hairs); lamina apex mucronate (vs. obtuse to rounded); peduncle up to 11 cm long (vs. puduncle up to 19 cm long); inflorescence mostly solitary, rarely singly branched (vs. branched 2–3 times); and with one pink outer tepal of staminate flowers (vs. uniformly white).

Figures

FIGURE 2. Illustration of Begonia fritschiana. A. Habitat; B. Lamina adaxial view; C. Stipules; D. Unopened staminate flower; E. Staminate flower; F. Stamens; G. Pistillate flower lateral view; H. Pistil; I. Bracts; J. Unopened staminate flower; K. Cross section of the ovary (Illustration by R.J. Lamparas based on V.B. Amoroso 31059)

FIGURE 3. Begonia fritschiana. A. Habit; B. Leaf adaxial surface; C. Leaf abaxial surface; D. Close-up view of abaxial leaf surface with marginal hairs (arrow); E. Inflorescence; F. Staminate flower lateral view with hairy pedicel and peduncle (inset); G. Pistillate flower front view with 5 tepals; H. Mature fruits with hairy pedicels; I. Uniformly white tepals of pistillate flower with green glabrous capsule; J. Creeping rhizome with persistent stipules; K. Transverse section of ovary with unequal wings (All from V.B. Amoroso 31059)

FIGURE 4. Habitat of B. fritschiana (encircled) among boulders with a thin layer of soil, liverworts, and some other herbaceous plants.