A Revision of the Chinese Endemic Orychophragmus (Brassicaceae)

Abstract

Orychophragmus consists of two species endemic to China. The new combination 0. limprichtianus is proposed. Cardamine hickinii and Alliaria grandifolia are reduced to synonymy of 0. limprichtianus, and C. potentillifolia, 0. dffusus, and 0. taibaiensis are reduced to synonymy of 0. violaceus. During the revision of the Brassicaceae for the Flora of China, it became quite clear that the limits of some of the Chinese species of Alliaria Heister ex Fabricius and Cardamine L. have been confused, and such taxa are more appropriately placed in Orychophragmus. Although Orychophragmus is endemic to China, Ying et al. (1993) did not include it in their work of the endemic Chinese genera. Perhaps they were influenced by Schulz (1923, 1936) who recognized two species, 0. violaceus (L.) O. E. Schulz (China) and 0. winkleri (Regel) 0. E. Schulz (Afghanistan, Tajikistan, Turkmenistan, Uzbekistan), of which the latter was appropriately placed by Botschantsev (1966) and Hedge (1968) in Spryginia Popov. The latter differs from Orychophragmus by having the median filaments connate throughout, flattened fruits, and incumbent By contrast, Orychophragmus has all filaments free, terete or slightly 4-angled fruits, and conduplicate As herein delimited, Orychophragmus consists of two species. One of these, 0. violaceus, is highly variable, and several of its segregates have been recognized as distinct species. The second species, 0. limprichtianus, was previously described as Cardamine or Alliaria, but as shown below, it belongs to Orychophragmus because it has conduplicate cotyledons, a feature characteristic of the tribe Brassiceae and not known in any other native Chinese species of the Brassicaceae. Orychophragmus was excluded by G6mez-Campo (1980) from the Brassiceae because (p. 5) it has somewhat conduplicate cotyledons. However, we have examined the cotyledonary position in both species of the genus and found them to be typically conduplicate, as in the vast majority of the tribe. Recent studies by Anderson and Warwick (1999), using two phylogenetically informative isozyme duplications, supported the inclusion of Orychophragmus in the tribe Brassiceae. The Brassiceae are a monophyletic tribe readily distinguished from the rest of the Brassicaceae by having conduplicate cotyledons and/or transversely segmented (heteroarthrocarpous) fruits (Al-Shehbaz, 1985), though such fruits are lacking in Orychophragmus. Although Orychophragmus violaceus differs substantially from 0. limprichtianus in flower size (see key) and in having auriculate instead of non-auriculate cauline leaves, the two species belong to the same genus because they have similar basal leaf morphology (e.g., not rosulate, long petiolate, with leafletlike lateral lobes, base often cordate, margin coarsely crenate with teeth ending in apiculae), pilose indumentum of simple trichomes, saccate lateral sepals, apiculate anthers, decurrent 2-lobed stigmas, oblong and alveolate-reticulate seeds, and conduplicate The differences in flower size and color probably are adaptations to different pollinators. Perhaps one of the most interesting things is that Orychophragmus limprichtianus was treated as two species, one each placed in Cardamine of the tribe Arabideae and Alliaria of the Sisymbrieae (An, 1987; Cheo, 1987; Zhang, 1993). However, the appropriate generic placement of this species in Orychophragmus and the affiliation of the genus to the tribe Brassiceae were overlooked because these authors did not examine the cotyledonary position. In light of these findings, the genus Orychophragmus is revised, and detailed descriptions are provided for it and its two species. Orychophragmus Bunge, Mem. Acad. Sci. Saint P'tersbourg 2: 81. 1835. TYPE: Orychophragmus violaceus (L.) 0. E. Schulz. Herbs annual, biennial, or rhizomatous perennial. Trichomes absent or simple. Stems erect to NovoN 10: 349-353. 2000. This content downloaded from 157.55.39.104 on Mon, 20 Jun 2016 05:28:05 UTC All use subject to http://about.jstor.org/terms