Menonvillea rigida Rollins (1955: 14)

Salariato, Diego L., Zuloaga, Fernando O. & Al-Shehbaz, Ihsan A., 2014, A revision of the genus Menonvillea (Cremolobeae, Brassicaceae), Phytotaxa 162 (5), pp. 241-298 : 266-267

8. Menonvillea rigida Rollins (1955: 14) . Type:— ARGENTINA. [Provincia de Neuquén]. Arroyo Manzana, Andes Expedition 38– 41°S, 1925−1927, H . F . Comber 1130 (holotype K!; isotype GH! fragm. ex K) .

Perennials with thick, deep, fleshy to woody, branched caudex. Stems (6−)9−25(−30) cm, fleshy or more frequently woody, thick, erect, generally unbranched above, with numerous leaf scars, pubescent to canescent with simple, terete, straight, retrorse or less frequently spreading to antrorse trichomes 0.5−1.2 mm long. Leaves cauline, subsessile, cuneate, 7−18(−25) × (3−) 5−8 mm, canescent, generally with retrorse trichomes or sometimes antrorse to spreading adaxially, base cuneate to attenuate, margin entire, apex 3-lobed or 3-dentate. Racemes terminal, ebracteate or frequently bracteate proximally, corymbose, densely flowered, slightly elongated in fruit, 3− 6 cm long; rachis straight, canescent; fruiting pedicels ascending to divaricate or reflexed, straight to recurved, (6−) 8−14 mm long, densely pubescent with spreading trichomes. Sepals oblong, 4−6 × 2−2.5 mm, pubescent, erect, not saccate, caducous, margin scarious; petals white, spatulate to broadly so, 6.5−9 × 1.5−3.5 mm, clawed, not papillate at base; stamens tetradynamous; filaments free, erect, dilated and not papillate at base, 3−5.5 mm long; anthers narrowly oblong, 1.2−2 mm long; nectar glands confluent, ringlike, subtending bases of all filaments. Fruits subglobose, pubescent with spreading trichomes; valves 3-winged, conspicuously veined, 9−13(14) × 7−12 mm, emarginate apically, wings 1.5−2(−2.7) mm wide; gynophore 1.5−2(−3) mm long; style 2−3 mm long; stigma slightly decurrent. Seeds ovate, ca. 4 × 3 mm, wingless, flattened; cotyledons accumbent.

Distribution and habitat:— Menonvillea rigida is endemic to Argentina where it grows in north-central Patagonia (Neuquén and Río Negro) on rocky slopes at elevations of 1500−1900 m ( Fig. 12H ).

Phenology:— Flowers from December to March.

Taxonomic notes:— Although Rollins (1955) considered Menonvillea rigida to be morphologically related to M. nordenskjoeldii , the species also seems to be related to M. cuneata , as both have simple, terete, straight and usually retrorse trichomes 0.5−1(−1.2) mm long, compared to trichomes 1−2(3) mm long in M. nordenskjoeldii . Furthermore, their leaves are 3-dentate to slightly 3-lobed, whereas those of M. nordenskjoeldii are deeply 3−5(− 7)-lobed at apex. Based on these similarities, Al-Shehbaz (2008) included M. rigida in the synonymy of M. cuneata . However, the former has thick and conspicuously woody stems with numerous leaf scars and fruit valves 9−13(−14) mm long. By contrast, M. cuneata has generally thin, fleshy or slightly woody stems without leaf scars, and the fruit valves are (4−)5−8(−11) mm long. Also, leaves of M. rigida have trichomes antrorse adaxially and retrorse to spreading abaxially [as in Diem 933 (LIL, SI), Diem 2959 (BAB), Neumeyer 596 (SI)], whereas those of M. cuneata have retrorse to spreading trichomes on both surfaces. Molecular phylogenies agree with Rollins (1955) in recognizing M. rigida as most closely related to M. nordenskjoeldii .

Representative Specimens:— ARGENTINA. Neuquén: Depto. Huiliches, Parque Nac. Lanín , ladera N, subiendo al refugio por sendero de mulas, 1 February 2000, Ezcurra 2979 ( BCRU) ; Depto. Lácar, Cerro Chapelco , 11 December 1963, Schajovskoy 7712 ( BAB) ; Depto. Los Lagos, Filo Machete al Cerro Rothkugel , 11 March 1945, Diem 933 ( LIL, SI) ; Villa Puerto Manzano , 11 February 1962, Diem 2959 ( BAB) . Río Negro: Depto. Bariloche, cerro Capilla , faldeo Sur , March 1942, Neumeyer 596 ( SI) .

Figures

FIGURE 12. Distribution of species of Menonvillea sect. Cuneata. A, M. cicatricosa. B, M. comberi. C, M. cuneata. D, M. frigida. E, M. macrocarpa. F. M. nordenskjoeldii. G. M. patagonica. H, M. rigida. I, M. spathulata. J, M. virens.