Impatiens tianlinensis S. X. Yu & L. J. Zhang, 2015

Zeng, Lei, Liu, Yan-Nan, Gogoi, Rajib, Zhang, Lin-Jing & Yu, Sheng-Xiang, 2015, Impatiens tianlinensis (Balsaminaceae) a new species from Guangxi, China, Phytotaxa 227 (3), pp. 253-260 : 254-257

Impatiens tianlinensis S. X. Yu & L. J. Zhang , sp. nov. ( Figs. 1–2 )

This species is similar to I. apalophylla Hook. f. (1908: 243) and I. clavigera var. auriculata in having racemose inflorescences, 4 lateral sepals, hammer-shaped capsules and ellipsoid seeds, but differs in sessile glanduliferous petioles, few-flowered inflorescences, incurved spur, yellow lower sepal without reddish patches, yellowish petals and lower sepal, and acuminate dorsal petal apex.

Type:— CHINA. Guangxi: Tianlin county, Cenwang Laoshan Mountain, in a valley near the river, 24°24’04.7” N, 106°23’09.5” E, ca. 1260 m, 9 Oct 2007, S. X. Yu 3731 (holotype PE!, isotype IBK!).

Herb, perennial, 50–80 cm tall, glabrous. Stems fleshy, erect, simple, robust; inferior nodes swollen. Leaves alternate, towards the stem apex aggregated; blade deep green above, pale green beneath, obovate to oblanceolate, 10–15 (–18) cm long, 5–8 cm wide, apex acuminate, base cuneate, margin crenate, with fimbriae between the teeth; lateral veins 7– 9 pairs. Petioles (0.5–) 1–2 cm (or upper leaves subsessile) with several short clavate glands. Inflorescence racemose; racemes solitary in the upper axils, 10–15 cm, 3–5 (–7) flowered, bracteate. Pedicels thin, 15–20 mm. Bracts ovate, 3–5 mm, acute, deciduous. Flowers yellowish or cream. Lateral sepals 4, the outer 2 small, ovate, symmetric, 5-veined, yellowish-green, 5–8 × 3–5 mm; the inner 2 large, 7–8× 2–3 mm, sickle-shaped, inaequilateral, apex acuminate or caudate. Lower sepal 2.5–3.5 cm excluding spur, saccate, abruptly constricted into a 1–1.5 cm involute spur. Dorsal petal 10–12 × 7–9 mm, ovate, apex obtuse, base broadly cuneate, midrib obvious, with a slight dorsal crest. Lateral united petals yellow, 2–2.5 cm; lower lobe 10–15 mm, oblong; upper lobe 20–25 mm, elliptic, apex emarginate, middle of inner margin without appendage. Stamens 5, filaments linear, 2–3 mm, anthers obtuse. Ovary clavate, superior part inflated. Capsule hammer-shaped, 1.5–2cm, seed ellipsoid.

Palynology:—Pollen grains of Impatiens tianlinensis , I. apalophylla and I. claviger var. auriculata are all triangular in polar view, tricolpate with long, thin colpi, an exine with reticulate ornamentation and dense granules in lumina ( Fig. 3A–C ). Pollen grains of I. tianlinensis are 30.13 (29.62–30.47) × 12.95 (12.68–13.54) μm, whereas those of I. apalophylla are very much narrower, ca. 31.85 (30.96–32.73) × 5.57 (5.13–6.75) μm. Pollen grains of I. clavigera var. auriculata are 27.09 (26.58–28.63) × 12.78 (12.34–13.69) μm..

Phenology:—Flowering and fruiting from September to November.

Ecology:—This new species grows in a valley at an elevation of 1100–1300 m. s. m., in a disturbed forest. The population is apparently small.

Distribution:—Except the type locality, I. tianlinensis is also known from Lingyun, Fengshan, Leye and Nandan of Guangxi.

Etymology:—The specific epithet ‘ tianlinensis ’ refers to the type locality.

Additional examined materials: — China. Guangxi: Lingyun, Lingyun Expedition 3-6098 (GXMI); Fengshan, Fengshan Expedition 4-7-76 (GXMI); Leye, Leye Expedition 3-30133a (GXMI); Nandan, Nandan Expedition 4-5- 113, 4-5-300, 4-5-472, 4-5-750 (GXMI).

Figures

FIGURE 1. Impatiens tianlinensis: A. habit; B. partial view of petiole; C. flower (laterial view); D. flower (front view); E. bractlet; F. outer lateral sepal; G. inner lateral sepal; H. lower sepal (lateral view); I. dorsal petal; J. lateral united petals; K. capsule; L. transection of ovary (Drawn by Y. B. Sun from S. X. Yu 3731).

FIGURE 2. A–F: Impatiens tianlinensis. A. flower branch; B. racemose inflorescence; C. upper stem; D. flower (front view); E. flower (dorsal view); F. flower (lateral view). G–I: I. apalophylla. G. habitat; H. flower (lateral view); I. flower (front view). J–L: I. clavigera var. auriculata. J. flower branch; K. flower (front view); L. flower (lateral view) (photographed by S. X. Yu).

FIGURE 3. Pollen micromorphology under SEM.A–C: Impatiens tianlinensis.A. polar view, bar = 6 μm; B. equatorial view, bar = 5 μm; C. partial view, bar = 2 μm. D–F: I. clavigera var. auriculata. D. polar view, bar = 6 μm; E. equatorial view, bar = 6 μm; F. partial view, bar = 2 μm. (Voucher specimen of I. clavigera var. auriculata, S. X. Yu 4036, deposited in PE). G–I: I. apalophylla. G. polar view, bar = 5 μm; H. equatorial view, bar = 5 μm; I. partial view, bar = 2 μm (Voucher specimen of I. apalophylla, S. X. Yu 4042, deposited in PE).