Begonia normaaguilariae M.D. Angeles, Rubite, & Tandang

Delos Angeles, Marjorie D., Rubite, Rosario R., Chung, Kuo-Fang, Buot Jr, Inocencio E. & Tandang, Danilo N., 2022, Begonia normaaguilariae (section Baryandra, Begoniaceae), a new species from the limestone forests of Samar Island, Philippines, Phytotaxa 541 (1), pp. 49-56 : 51-54

Begonia normaaguilariae M.D. Angeles, Rubite, & Tandang sp. nov. ( Figures 2 & 3 )

Type:— PHILIPPINES • Samar Island, Municipality of Paranas , Samar Island Natural Park , forest over limestone, elevation 120 m, 11°48’51”N, 125°9’39”E, 2 June 2021, MD delos Angeles 273 (Holotype: PNH!; Isotype: CAHUP!) .

Diagnosis:— Begonia normaaguilariae bears a superficial resemblance to B. biliranensis in reference to the shape of leaf foliage in having asymmetric leaf blades with glabrous adaxial surface, white-puncticulate abaxial surface, with inequilateral cordate base, repand or repand-lobed margins and acuminate apex. The new species, however is distinguished by having stipules with a conduplicate stipule towards the acute to acuminate (vs acuminate) apex, longer (190–203 vs 110–180 mm) petioles, and entirely glabrous (vs brown–setose on nerves) abaxial leaf surface and it has much larger overall size of staminate and pistillate flowers.

Description:— Monoecious terrestrial perennial herbs, ca. 9 cm tall. Underground rhizome is brown to green with a shade of light brown, prostrate, terete, short, stout, about 8 cm long, 6.7–7.2 mm thick, glabrous, associated few lenticels, internode 8.3–11.1 mm long. Stipules persistent, membranous, red or light pink to light brown, ovatetriangular, asymmetric, cucullate, 11.45–14.14 mm long, broadside 7.2–8.2 mm wide, narrow side 4.0– 4.5 mm wide, prominently keeled at base to apex, keel with long red hairs on the abaxial part, 11.3–13.2 mm long, extending up to the apex, margin entire, conduplicate at the upper part, apex acute to acuminate. Leaves alternate, petioles are light brown, terete, erect, 4.7–5.1 mm thick at base, becoming narrow 3.5–3.8 mm at the middle, and 2.4–3.1 mm at tip, entirely glabrous. Leaf blades pale to dark green, glossy above, whitish-green below, minutely puncticulate, coriaceus, surface glabrous, broadly asymmetric broadly ovate, 7.8–9.5 cm from point of attachment towards the tip, up to 10.4–13 cm from the longest basal lobe to the apex by 6.5–7 cm at widest point, base inequilateral cordate, margin repand or repand-lobed to sharply toothed, apex acuminate. Young foliage light-brown to light pink on adaxial and abaxial side, glossy, suborbicular with prominent venation below, margin strongly curved forming deeply-crenate lobes with light-pink outline, succulent and glabrous. Venation basally, 5–8 nerves, divided into 2 secondary veins, with reticulate tertiary veins arrangement, all veins prominent above, only primary veins below raised near the petioles becoming sunken towards the margin. Bracts caducous. Inflorescence axillary, erect, dichotomously branched 3 or 4 times; pedicel white; peduncle light brown to green towards the tip, terete, ca. 8–11 cm long, glabrous; bracteoles caducous on old branches, present on young ones, ovate, 3–5 nerved, margin entire, apex subobtuse, glabrous. Staminate flower: pedicel 9.1–9.2 × 0.8–0.9 mm, terete, erect to slightly curve at top, glabrous, outer 2 broadly ovate or orbicular-ovate, 8.2–9(–10) × 8.0–8.3(–8.8) mm, margin entire, rounded at apex, inner 2 oblanceolate to narrowly obovate, 7.1–7.5(–8.4) × 2.5–4.4(–4.5) mm, margin entire, apex rounded to slightly retuse; androecium actinomorphic, 3.0– 3.6 mm wide, stamens 47–53, filaments 0.8–1.0 × 0.07–0.1 mm, joined at base; anthers yellow, obovoid, 0.8–0.9 × 0.6–0.8 mm, retuse at apex. Pistillate flower: pedicel white, erect, 7.5–7.7 × 0.7–1.1 mm; tepals 4, white, glabrous, outer 2, broadly ovate or orbicular-ovate, 10.3–11.3 × 9.2–9.9 mm, margin entire, apex rounded, inner 2, oblanceolate to narrowly obovate, 8.9–9.2 × 2.6–2.7 mm, margin entire, apex rounded; ovary pinkish-white, trigonose-obovate, 6.4–7.1 × 4.1–4.6 mm (excluding wings), glabrous, base and apex somewhat acute; 3-winged, greenish-white, wings unequal, crescent-shaped with entire margin, 9.4–10.6 mm long, abaxial wings much wider, 2.8–5.5 mm than lateral wings, 2.8–3.9 mm wide; 3-locules, placentae axile; styles 3, united at base, light green, stigmas 2-cleft, twisted, papillose and yellow green. Capsules brown, pedicel 15.6 mm long, curved downward; body trigonous-oblong, green, 7.4–9.9 × 3.5–4.0 mm (wings excluded), slightly curved, base and apex acute, glabrous, wings unequal 8.6–9.7 mm long, crescent-shaped, abaxial wing broader, 3.3–5.5 mm wide, lateral wings 2.8–3.9 mm wide.

Distribution and Ecology: — Begonia normaaguilariae is known only from the type locality, Samar Island Natural Park, Municipality of Paranas, Samar Island. It was observed to grow under shaded and moist environments. Furthermore, it was recorded to thrive along the trail on soil but more prominently on limestone rock crevices. The fibrous roots are covered with dried forest litter.

Etymology: — The specific epithet “ normaaguilariae ” is in honor of the late Professor Norma O. Aguilar, the former professor of plant systematics and head of the Plant Biology Division, Institute of Biological Sciences, University of the Philippines Los Baños (UPLB). Her taxonomic contributions on the plant families Poaceae and Fabaceae , have inspired many botanists to follow her stead.

Phenology: — This new species was observed to bear flowers and fruits in March to October.

Conservation status: — This new species, thus far, is found only in a single locality. During the botanical inventory conducted last March 2016, only 2 mature individuals were noted within the two 10 × 10 m quadrats in a 0.5 km transect line and with less than 30 flowering and fruiting individuals observed outside the sampling area (D.N.T. pers. observ.). Following the Red List criteria of the IUCN Standards and Petitions Subcommittee (2019), very small population size of <50 individuals, restricted area of occupancy of <10 km 2, few locations, and restricted distribution to forests over limestone, Begonia normaaguilariae is hereby proposed as Critically Endangered. Although the area is protected under Proclamation No. 442. 2003, pursuant to the National Integrated Protected Areas System (NIPAS) Act of 1992, habitat disturbance as a result of anthropogenic activities such as clearing of pathways for tourism among others, places this species at a very high risk. Such activities will have a negative impact leading to a decline in its population.

Notes: — Begonia normaaguilariae is morphologically similar to B. biliranensis with regard to the obliquely ovate leaf shape with repand or somewhat repand-lobed margin, obovoid anther shape, and spiral stigma formation. However, this new species is distinguished by its glabrous (vs brown setose) rhizome, petiole, and leaf blades, 5–8 (vs 10) nerves, a smaller (47–53 vs 60) number of anthers, and a longer (0.8–0.9 vs 0.6 mm) anther. The margin of this new species differs from young leaf (deeply-crenate) to mature leaf (repand or repand-lobed to sharply toothed). Furthermore, the distribution of this new species is restricted to forests over limestone. A detailed comparison can be seen in Table 1 which provided salient features to further differentiate the two species.

Figures

FIGURE 2. Begonia normaaguilariae M.D.Angeles, Rubite, & Tandang. A. Habitat; B. Habit; C. Stipule; D. Rhizome; E,F. Different forms of leaf (Adaxial); G. Leaf (Abaxial); H. Inflorescence; I. Staminate flower adaxial view; J. Staminate flower lateral view; K. Pistillate flower adaxial view; L. Pistillate flower lateral view; M. Infructescence; N. Fruit; O. Transverse section of capsule (Photos credits: DN Tandang: A,C,E,H–O; MD delos Angeles: B,D,F,G).

FIGURE 3. Begonia normaaguilariae M.D.Angeles, Rubite, & Tandang. A–C. Different developmental stages of leaf blades (Adaxial); D–F. Different developmental stages of leaf blades (Abaxial). G–J. Margin of mature leaf blade; K,L. Young foliage with strongly curved margin forming deeply-crenate lobes; M,N. Leaf base and petiole (Adaxial and abaxial) (Photos credits: MD delos Angeles: A–H, K–M; DN Tandang: I,J).