Pulvinatusia J.P. Yue, H.L. Chen, Al-Shehbaz & H. Sun, 2022

Chen, Hong-Liang, Al-Shehbaz, Ihsan A., Qian, Li-Shen, Zhang, Jian-Wen, Xu, Bo, Zhang, Ti-Cao, Yue, Ji-Pei & Sun, Hang, 2022, Pulvinatusia (Brassicaceae), a new cushion genus from China and its systematic position, PhytoKeys 189, pp. 9-28 : 9

Pulvinatusia J.P. Yue, H.L. Chen, Al-Shehbaz & H. Sun gen. nov.

Fig. 2

Type.

Pulvinatusia xuegulaensis J.P. Yue, H.L. Chen, Al-Shehbaz & H. Sun.

Diagnosis.

As indicated above, the monospecific Pulvinatusia xuegulaensis and Ladakiella klimesii are the only members of the tribe Crucihimalayeae with pulvinate and scapose habit and pink to whitish pink petals. The former differs by having simple and fewer forked trichomes, thin papery leaves, solitary flowers, caducous sepals, and glabrous, somewhat flattened fruits. By contrast, L. klimesii has subdendritic trichomes with finely branched rays, thick and fleshy leaves, 2-4-flowered racemes, persistent sepals, and pubescent and terete fruits.

Description.

Herbs perennial, cespitose, scapose, pulvinate, with well-developed caudex covered with petioles of previous years. Trichomes simple, mixed with fewer forked stalked ones. Leaves densely imbricate, sessile, thin, papery, densely long ciliate, midvein obscure, adaxially concave to nearly flat, base attenuate, apex subacute. Flowers solitary on short pedicels originating from axils of basal leaves. Fruiting pedicels stout, erect or ascending, often hidden among basal leaves. Sepals oblong, abaxially with trichomes similar to those on leaves. Petals whitish pink to pink; blade obovate to suborbicular, apex obtuse, rounded or rarely acute, claw subequaling or slightly shorter than sepals. Stamens 6, slightly tetradynamous; filaments unappendaged, free; anthers ovate or oblong, obtuse at apex. Ovules 2 or 3 per ovary, placentation parietal. Fruits dehiscent, latiseptate, ovoid to ellipsoid, inflated; valves thick leathery, carinate; replum rounded, visible; septum complete; style obsolete or short and to 0.4 mm long, stout; stigma capitate, entire, unappendaged. Seeds aseriate, wingless, oblong, seed coat smooth, not mucilaginous when wetted; cotyledons accumbent.

Name derivation.

The generic name is derived from the pulvinate habit of the plant, and the species epithet from the Xuegu La (Xizang, China), where the type collection was made.

Figures

Figure 2. Images of Pulvinatusia xuegulaensis A and B fruiting plants C fruits D septum and replum E and F seeds G and H flowering plants I and J stems K leaves. Scales bars: 1 mm. - Photos: A-F & I-K by Lishen Qian G and H by Jianwen Zhang.