The Chilean Agallis and Californian Tropidocarpum (Brassicaceae) are Congeneric Ihsan A. Al-Shehbaz Missouri Botanical (arden, P.O. Box 299, St. Louis, Missouri 63166-0299, U.S.A. Robert A. Price P.O. Box 8082, Athens, Georgia 30603, U.S.A.Atis't'tI (. Agatllis is reduced to s5vnoninv of Tro-pidocaurtm, and the new combiniation T lItuatumis therefore proposed. The morphological similari-ties in plant aspect, flowers, and fruit between thetwo genera are presented. and a key to species of'Tropidocarpmn is given. I)isjncition between Northand South American congeners of the Brassicacteaeis discussed. Key words: Agallis, North-South American dis-junctions. Tropidocarpuin. The recent discovery of the nionoltypic 7Tissel-rnannia (Al-Shehlbaz, 1999) i)romlp)ted colmparativeand nmolecular stuldies on the Californian Tropido-carpium Hooker (2 spp.) and Chilean Agallis Phi-lippi (monotypic). The results of that study will I)epul)lished elsewhere. The monotylpie Twisselnimafnia was previouslyknown fromul two collections from Kings County, Cal-ifornia, LatRue s.. (UCR) aln T7ylor & Ertteri17098 (MO. IUC). but a third co'llection. Tnissel-mann 1(0447 ((:)A). was collected fromi Kern(County on a canal bank at the southern end of KernNational Wildlife Refuge. Agallis lunttat (Barneoud) (;ilg & Muschler exO. E. Schulz is restricted to central Chile and isknown froin several old collections (see below).while Tropidoctarinn grarile Hlooker is wicespreadtin northern Baja (alifornia and southern Californianorthward through the central valley north of SanFrancisco (Rollins, 1993a: Wiggins. 1980). By con-trast, 7 capttlrideurn E. I.. (;reene, whlich is pre-suimed extinct (Hollins, 1993a), is known fronm oldlercollections made near Mount D)iallo at the north-westerni part of San Joaqulin Valley. The similarities between Agalli., Tropitdocarpnti,and 7Tlisse/mlnania include annual habit, indumen-turn of coarse simple tric(honics mixed with smallerforked ones. pinnatisect to pinnatifid petiolateleaves, racemes bractteate tlhroulghoiit yellow flow-ers occasionally tinged withi pitirlle, dilated basesof staminail filainents, angustiseptale fruits, ilru i-Nov\N 11: 292-293. 2001.laginous seeds, andi incumbtent cotyledons. Thcissel-mannia is easily sieparated from the other two byhaving obdeltoid, 4-to 8-seeded silic hs and an-trorsely hirsute fruit valves that are tuberculate-ru-gose, thick leathery to subwolodi v on the distalhalves, and abruptly narrowed to apex. In contrast,Agallis and Tropidocarctim have linear or otlong toelliptic, 16-to 70-seeded siliques and unifornlyleathery, retrorsely hirsute (except when glabres-cent) valves with iobtuse apices. Except for thevalve number, which is two in Agallis /anamt andfour in 7. cappariaeumn, tie other differences sep-arating the two species are quantitative. The in-crease in valve nuimber is a highly unusual featurein the Brassicaceae. and within Tropidoc'irpuinr thefruits of 7: grtcile aire 2-valved whereas those of Tcapparideucn are 4-valved. The only other docu-mented example is in the unrelated genus RorippaScopoli (ca. 75 spp.), in which one species. /. Rbar-bareinolia ()DC.) Kitagawa. has 4-to 6-valved fruits.On the basis of these remarkable morphologicalsimilarities betweeln Aallis andl Tropidorarplmnn thetwo genera are herein united. Trtopidtoc'arm tliecomes the fifth genuls of Bras-sicacteae with known disjuncit distribution in tem-perate Northi and South America. Mancoa Weddellis prlpresented byi sevenl species in nortlhernl Mexicoand adjacent Texas anld four species in southernPeru, Bolivia. and northelrn Argentina (Rollins,1941; Al-Shehbaz, 1990). Pcnnellia Nieuwhuia in-ctlules 11 spec'ies, of which eight are dislributedfroni northern Guatemala into Mexico and thesoiuthwestern IUniited States (Hollins. 1980, 1993a),one in southern Bolivia and northern Argentina (Al-Shehhaz. 1990), and two were treated by Iollins(19931) in Arabis ibut lnow belong to IPennellia (Bai-ley, 2001; Price et al.. in pr(ess). Other South Amner-ican species listed by Schullz (1924, 1936) unlterHeleroth/rix Hydbe-"g or Pennellia belong to thepoorly defined Sisnmbriunl I,. sensu lato (Al-Sheh-baz, 1990). The fo'urth genus with disjunct distribution is
BioStor
