Lepidium yelarbonense Al-Shehbaz, 2023

Al-Shehbaz, Ihsan A., 2023, Lepidium yelarbonense (Lepidieae; Brassicaceae), a new species from Australia, Phytotaxa 585 (4), pp. 298-300 : 298

Lepidium yelarbonense Al-Shehbaz , sp. nov.

Diagnosis:— Lepidium yelarbonense differs from L. mononplocoides , its Australian closest relative, by being a completely glabrous perennial with subterete to slightly flattened fruiting pedicels 0.3–0.4 mm wide, fruits with straight, subobtuse, non-constricted valve apex, and styles subequal to slightly exserted from the apical fruit notch.

Type: — AUSTRALIA. Queensland: Darling Downs District , roadside S of Yelarbon, gilgaed areas on clay soils, salt scalded, 17 December 2005, R. J. Fensham 5277 (holotype, BRI AQ-781534 ). Figure 1B .

Description:—Herbs, perennial with woody base. Trichomes absent. Stems 40–50 cm tall, glabrous, simple at base. Basal leaves subrosulate, narrowly linear, soon withered; cauline leaves linear, undivided, sessile, not auriculate at base, entire. Racemes ebracteate, elongated in fruit; rachis straight, glabrous; fruiting pedicels 3–4 mm long, subterete to hardly flattened, 0.3–0.4 mm wide distally, glabrous, divaricate, straight, persistent. Sepals ovate, ca. 1 mm long, caducous, ascending, equal; petals rudimentary; stamens 4, equal in length, median; filaments glabrous, dilated at base; anthers ovate, ca. 0.2 mm long; nectar glands confluent, low, flat, subtending bases of filaments; ovules 2 per ovary. Fruits dehiscent, suborbicular, ca. 5 mm in diam, strongly angustiseptate, not inflated; valves papery, glabrous, smooth, strongly keeled, winged all around, with straight, apically subobtuse non-constricted wings, valve apices not overlapping; apical notch narrowly U-shaped, ca. 0.3 mm deep; septum complete; style subequal to slightly exserted from apical notch, with obsolete lateral horns; stigma capitate, entire. Seeds ovate, ca. 2 mm long; cotyledons incumbent, entire.

Phenology: —Fruiting in December.

Distribution: —Endemic to Queensland.

Discussion: — Lepidium yelarbonense most closely resembles L. monoplocoides Mueller (1855: 35) , an endemic of New South Wales and Victoria, than any other native Australian species. However, it is substantially different by being a perennial with woody base (vs. herbaceous annual) that is glabrous throughout (vs. scabrous at least distally with flattened tuberculate trichomes), with glabrous (vs. scabrous) stems ca. 50 (vs. 4–20) cm tall, glabrous and subterete to slightly flattened (vs. usually tuberculate and strongly flattened) fruiting pedicels 0.3–0.4 mm (vs. 0.45–0.6(–0.65) mm) wide distally, fruit valves with straight, apically subobtuse non-constricted wings (vs. sharply acute apically with straight or overlapping valve apices), and short styles to 0.1 mm long (vs. obsolete) that are subequal to exserted from (vs. included in) the apical fruit notch and with obsolete (vs. distinct) pair of horns just below the stigma ( Figure 1 ).

Additional collection examined (paratype): — AUSTRALIA. Queensland: Darling Downs District, Yelarbon , 19 December 1934, S. L. Everist 875 (GH).

Figures

FIGURE 1. Distal half of fruits of Lepidium monoplocoides (A) and L. yelarbonense (B). Drawn byAl-Shehbaz from Jeanes 1721 (MEL) and Everist 875 (GH), respectively.