Cardamine karol-marholdii Al-Shehbaz, 2022

Al-Shehbaz, Ihsan A., 2022, Cardamine karol-marholdii (Cardamineae; Brassicaceae), a remarkable new species from Mexico, Phytotaxa 555 (2), pp. 213-216 : 213-216

Cardamine karol-marholdii Al-Shehbaz , sp. nov.

Diagnosis:— Cardamine karol-marholdii is substantially different for any congener by being small subshrub with strongly flexuous racemes and short-node stems roughened by the persistent, indurated, triangular petiolar bases of cauline leaves.

Type: — MEXICO. Oaxaca, Dist. Miahutlán, Mpio. San Juan Mixtepec, summit of Quiexobaa , 16°17’00”N, 96°16’06”W, 3600 m, 24 April 1997, Eugene Hunn OAX-1017 (holotype, MO-6148030; isotype, MEXU, n.v.). Figures 1 , 2 .

Description: —Herbs perennial, somewhat subshrubby, puberulent. Trichomes straight, often slightly to distinctly recurved, subappressed, 0.01–0.12 mm long. Stems 10–30 cm tall, puberulent, erect, simple at base, branched above, wiry, strongly flexuous, slender, 1–3 mm wide, herbaceous in current-season growth, becoming woody subsequently, roughened by persistent, thickened petiolar bases, becoming slightly straight after first 3–4 years of growth. Leaves cauline, 7–13 mm long, puberulent, pinnatisect, (3–)5–7-lobed; petiole slender, 2–8 mm long, adaxially grooved, puberulent, strongly thickened, triangular, and to 1 mm wide at persistent base; lateral lobes (2 or) 4 or 6, linear, somewhat wider distally, about same size as terminal lobe, slightly curved, often subappressed, and overlapping along entire length, 1–5 × 0.13–0.25 mm, slightly grooved adaxially, base attenuate, margin entire, slightly involute, apex acute. Racemes 5–12-flowered, hardly elongated in fruit, bracteate along lowermost 1–3 flowers; rachis strongly flexuous, puberulent; fruiting pedicels 5–10 mm long, slightly flattened, recurved, puberulent adaxially, glabrous abaxially. Sepals oblong, 1.8–2 mm long, glabrous or subapically puberulent with few trichomes, membranous at margin; petals white, obovate, 4–5 × 1.5–2 mm, attenuate into claw 0.8–2 mm long; filaments white, 1.5–2 mm long; anthers ovate, ca. 0.8 mm long; ovules 10–12 per ovary. Fruit linear, 1.5–2.5 cm × ca. 1 mm, sparsely puberulent along replum at least when young, subsessile or on gynophore to 0.5 mm long; style 1–2 mm long. Seeds oblong, 1.5–1.6 × 0.7–0.8 mm long.

Phenology: —late-season flowering and fruiting in April.

Distribution: —endemic to Mexico and known thus far only from the type collection.

Eponymy: —The species is named in honor of the eminent Slovak botanist Karol Marhold (1 June 1959 –), a staff of the Institute of Botany and academician, Slovak Academy of Sciences (Bratislava), professor in Charles University (Prague, Czech Republic), an outstanding expert on the Brassicaceae , and the world authority on the genus Cardamine .

Discussion: — Cardamine karol-marholdii is easily distinguished from all other species of the tribe Cardamineae by its somewhat subshrubby habit and has slender, strongly flexuous, woody stems with persistent, thickened bases of petioles that make the rather rough. It also has curved, pinnatisect leaves with overlapping, appressed, lobes grooved adaxially. All other species of the tribe are annuals or perennials with herbaceous stems straight to slightly flexuous but never roughened by their petiolar bases of caducous cauline leaves. The racemes of C. karol-marholdii are bracteate basally, but unlike the numerous other bracteate species of the genus, the rachis is profoundly flexuous, and the young fruits are puberulent at least along the replum. The Cardamine accounts of Rollins (1993) and Al-Shehbaz et al. (2010) do not relate this novelty to any other species, and the only species in all North and Central America with flexuous racemes is the unrelated C. macrocarpa Brandegee (1906: 233) , an annual herb of Texas and northern Mexico (Coahuila and Nuevo Leon) with slightly to distinctly flexuous (gyrate sensu Rollins) racemes, 5–9-foliolate cauline leaves with ovate to oblong, repand to dentate or lobed petiolulate leaflets, glabrous fruits 2.5–4.6 cm long, 14–22-ovuled ovaries, and ebracteate racemes. Its southernmost range is well over 1000 air kilometers away from the Mexican state Oaxaca, where C. karol-marholdii is known to grow so far.

Figures

FIGURE 1. Cardamine karol-marholdii. Image of the holotype Hunn OAX-1017 (MO-6148030).

FIGURE 2. Cardamine karol-marholdii. A. Plant. B. Leaf. C. Fruit. D. Seed. Drawn by Al-Shehbaz from the holotype, Hunn OAX-1017 (MO-6148030).