Impatiens pseudolongipes Gogoi, Norbu Sherpa, Borah, 2020

Gogoi, Rajib, Sherpa, Norbu & Borah, Souravjyoti, 2020, Taxonomic note on Impatiens longipes (Balsaminaceae) and description of the new species I. pseudolongipes, Phytotaxa 429 (3), pp. 217-224 : 218-223

Impatiens pseudolongipes Gogoi, Norbu Sherpa, Borah sp. nov. Fig. 3.

I. longipes sensu Gogoi, Borah, S.S.Dash & P.Singh (2018: 117) .

Close to I. longipes due to the arched-spreading inflorescence with yellow flowers, but differs in the subequally deltoid lateral sepals (vs. ovate or lanceolate lateral sepals), dolabriform distal lobe of the lateral united petals (vs. long twisted lorate distal lobe), capsule short clavate (vs. linear and more than double the length of former); it also shows similarities with I. scitula Hook.f. (1905: 14) due to yellow flower and clavate capsule, but differs in the arched-spreading inflorescence, lack of red spots in the lateral united petals (vs. lateral united petals are prominently red spotted), dolabriform distal lobe of the lateral united petals (vs. loriform in the former).

Type: — Arunachal Pradesh, West Siang, Menchukha, Yarlung, 2400 m, 24.07.2013, R. Gogoi 30521 (holotype CAL!, isotypes, CAL!).

Annual non-succulent herbs, branched, to 70 cm tall, stem terete, without swollen nodes, glabrous. Leaves confined mainly to upper parts, alternate, subsessile to petiolate; petiole slender, glabrous, 1–2 cm long, stipule present, persistent; lamina elliptic-lanceolate, 1.5–9.0 × 0.7–3.5 cm, base cuneate to attenuate, margin crenate, setose between teeth, apex acuminate, glabrous; veins 6–8 pairs, subopposite. Inflorescence axillary, exceeding the leaves, arched-spreading, pedunculate, peduncle glabrous, 8–10 cm long, 5–11 flowered, bud greenish yellow. Flower yellow, pedicellate, pedicel 1–1.3 cm, green, glabrous; bract subulate, 2–2.5 × ca. 0.5 mm, apex acuminate, green, caducous, midvein inconspicous, glabrous. Lateral sepals 2, obliquely ovate or falcate, ca. 2.5 × ca. 1 mm, apex aristate, yellowish green, margin transparent, membranous; lower sepal navicular, constricted into a spur, yellow, 0.7–1 cm deep, mouth beaked, beak ca. 1 mm long, spur 0.7–1 cm long, slightly upcurved, tip unifid, red, glabrous. Dorsal petal suborbicular, non-cucculate, 0.4–0.5 × 0.4– 0.3 cm, apex acute, non beaked, dorsally flat, yellow. Lateral united petals without blotches, bilobed, unequal, 1–1.2 cm long (whole), yellow; basal lobe ca. 0.7 × ca. 0.4 cm, obovate, not clawed, apex acute to obtuse, auricle inconspicous; distal lobe 0.2–0.5 × ca. 0.2 cm, elongated dolabriform, apex acute. Stamens upright, 1–2 mm tall. Capsule clavate, green, smooth, 1.5–1.8 × 0.15–0.25 cm, seeds many, ovate, brown, 1.5 mm across.

Phenology —May to October.

Etymology —The name pseudolongipes refers to its superficial similarities with Impatiens longipes .

Distribution and ecology —Usually grows in the stream sides of temperate mixed Rhododendron forests of Yarlung, Menchukha, West Siang district of Arunachal Pradesh in association with Impatiens scitula Hook.f. (1905: 14) and I. prainii Hook.f. (1905: 14) .

Figures

FIGURE 3. Impatiens pseudolongipes Gogoi, Norbu Sherpa & Borah: a. habit of the plant, b. inflorescence, c & d. lateral view of flower, e. stipular glands at the base of petiole, f. bract, g. lateral sepals, h. lower sepal, i. flower bud, j. dorsal petal (dorsal view), k. dorsal petal (ventral view), l. lateral united petals, m. upper part of pedicel with stamens encircling ovary, n. capsule, o. seeds. (photos by R. Gogoi)