Eutrema tianshanense G.Q. Hao, J.Quan. Liu & Al-Shehbaz, 2016

Hao, Guoqian, Al-Shehbaz, Ihsan A., Liang, Qianlong, Wang, Qian & Liu, Jianquan, 2016, Eutrema tianshanense (Brassicaceae), a new species from Tian Shan Mountains of central Asia, Phytotaxa 286 (1), pp. 23-31 : 28-29

Eutrema tianshanense G.Q. Hao, J.Quan. Liu & Al-Shehbaz , sp. nov.

Type:— China. Xinjiang: border of Nileke Xian and Wusu Shi, near glaciers, roadsides of mountain pass, 3200–3800 m, 28 June 2013, Liu, J. Q. & Hao, G. Q. 13062 (Holotype: SZ). Fig. 4 .

Herbs, perennial, glabrous throughout, with simple or few-branced caudex and fleshy roots. Stem (5–)8–14(–16) cm tall, erect, simple, one to several from caudex. Basal leaves rosulate, somewhat fleshy; petiole (0.5–)1–1.5(–2) cm; leaf blade broadly ovate to orbicular, 0.8–1.2 × 0.4–0.5 cm, base rounded or truncate, margin entire, apex rounded or obtuse; middle cauline leaves linear, narrowly elliptic, or oblanceolate, 1–1.3(–2) × 0.3–0.5 cm, pinnately veined, sessile, base cuneate, margin entire, apex obtuse. Racemes ebracteate, elongated considerably in fruit, several but <20-flowered; fruiting pedicels divaricate to ascending, curved upward or sometimes straight, 3–8 cm. Sepals ovate to oblong, 1.5–2 mm, deciduous, deep red or rose; petals white, spatulate, 2–3 × 0.7–1 mm; filaments white, ca. 2 mm; anthers oblong, ca. 0.2 mm. Fruit linear, lanceolate, to narrowly oblong, 5–8 × 1–2 mm, not torulose; valves cuneate at both ends; gynophore 0.1–0.4 mm; septum complete or rarely perforate; style ca. 0.4 mm. Seeds not seen. Flowering: May–July; fruiting: July–September.

Additional specimens examined: China. Xinjiang: Wulumuqi Xian, Urumqi Glacier No. 1, H. W. Jintian & Y. Yang 106 ( PE).

Eutrema tianshanense is most morphologically similar to E. edwardsii , and both have elongated racemes with divaricate-ascending fruiting pedicels curved upward. However, it differs from the latter by having broadly ovate to orbicular (vs. ovate to oblong) basal leaves rounded to obtuse (vs. subacute) at apex. More morphological studies at the population level are needed to establish whether or not there are other character that separate these two closely similar species. It is also morphologically similar to E. racemosum and E. heterophyllum , but differs from the former by having ascending (vs. somewhat reflexed) fruiting pedicels and from E. heterophyllum by having lax and elongated (vs. compact) fruiting racemes.

One specimen, Wu et al. 4892 ( HNWP, KUN) from Khungerab Pass, Tashkurgan Xian, was found to be morphologically similar to Eutrema tianshanense , but further molecular studies are needed to check whether or not it is genetically closely-related to the Tian Shan plants.

Figures

FIGURE 4. Different stages of Eutrema tianshanense: a. flowering stage b. young fruit stage c. mature fruit stage.