EDINB. J. BOT. 56 (3): 321-327 (1999) 321 IANHEDGEA (BRASSICACEAE), A NEW GENERIC NAME REPLACING THE ILLEGITIMATE MICROSISYMBRIUM I. A. AL-SHEHBAZ* & S. L. O'KANE Jr.f The generic name Microsisymbrium O.E. Schulz was illegitimate when described because it included the type of Guillenia Greene. The monotypic Ianhedgea is proposed to include one of the 12 species previously assigned to Microsisymbrium, i.e. M. minutiflorum (Hook.f. & Thomson) O.E. Schulz. The proper generic placement of the remaining 11 species of Microsisymbrium is presented. The following new combinations are made: Ianhedgea minutiflora (Hook.f. & Thomson) Al-Shehbaz & O'Kane, /. minutiflora subsp. brevipedicellata (Hedge) Al-Shehbaz & O'Kane, and Neotorularia quingshuiheense (Ma & Z.Y. Zhu) Al-Shehbaz, O'Kane & G. Yang. Keywords. Brassicaceae, Himalaya, Ianhedgea, Microsisymbrium, new generic name. INTRODUCTION Of the four species treated in his original account of Microsisymbrium O.E. Schulz, Schulz (1924) included three central Asian and Himalayan species and one, M. lasiophyllum (Hook. & Arn.) O.E. Schulz, from the western United States (Washington, Oregon, California, Arizona, Nevada, Utah) and Baja California, Mexico. In establishing the genus Guillenia Greene, Greene (1906) included five species, the first of which, G. lasiophylla (Hook. & Arn.) Greene, is clearly the generic type because he (Greene, 1904: 86) stated that: 'In arranging the sequence of species my custom is to place those first which seem to have the clearest claim to represent a genus; and therefore these stand as its type.' Payson (1923) and Rollins (1979) were correct in listing G lasiophylla as the type of Guillenia. As pointed out by Al-Shehbaz (1973), Schulz (1924, 1936) maintained Guillenia even after removing its type to Microsisymbrium; therefore, according to Article 52.1 of the ICBN, Microsisymbrium is illegitimate because it includes the generic type of Guillenia. Bonnet (1983) transferred all the Himalayan species of Microsisymbrium to Guillenia, and his account was followed by Hajra et al. (1993). Payson (1923), Al-Shehbaz (1973), and Rollins (1993) have reduced Guillenia to synonymy of Caulanthus S. Watson, whereas Buck (1995) maintained both genera. That does not mean, however, that all of the Asian species of Microsisymbrium should be automati- cally transferred to Caulanthus or Guillenia. Rather, a critical examination of the characteristics of all taxa involved clearly indicates that the Asian Microsisymbrium is a heterogeneous assemblage of taxa that belong to at least five genera (see below), * Missouri Botanical Garden, PO Box 299, St Louis, MO 63166-0299, USA. t Biology Department, University of Northern Iowa, Cedar Falls, IA 50614-0421, USA. 322 I. A. AL-SHEHBAZ & S. L. O'KANE of which none is related to the North American Guillenia or Caulanthus. As denned by Greene (1904), Guillenia clearly belongs to the group of genera previously placed in the Thelypodieae (Al-Shehbaz, 1973; Hauser & Crovello, 1982; Al-Shehbaz, 1985), a tribe exclusively restricted to the New World. If Guillenia were to be maintained, it should be very closely associated with Caulanthus (Al-Shehbaz, 1973). All except one of the eleven species previously placed in Microsisymbrium can easily be assigned to other genera. The single species, M. minutiflorum (Hook.f. & Thomson) O.E. Schulz, clearly stands alone, and we propose to place it in the monotypic Ianhedgea, a genus named in honor of Ian C. Hedge, an outstanding expert of the Old World Brassicaceae (Cruciferae). IANHEDGIA Ianhedgea Al-Shehbaz & O'Kane, gen. nov. Herba annua, pilis ramosis dendroidis. Folia pinnatisecta vel trisecta, petiolata; lobis integris filiformis, linearis, anguste oblongis, vel oblanceolato-linearis. Racemi fructi- feri laxi, ebracteati, flexuosi. Sepala erecta, nonsaccata. Petala alba vel pallide lilacina. Fructus lineares, teres, torulosi; septum completum, hyalinum; stylo nullo vel minuto. Semina uniseriata, humidate nonmucilaginosa; cotyleodones incumbentes. Type: Ianhedgea minutiflora (Hook.f. & Thomson) Al-Shehbaz & O'Kane. Herbs annual. Trichomes branched, finely dendritic. Stems erect, slender, often branched above. Basal leaves petiolate, not forming a rosette, finely pinnatisect or 3-sect; lobes 3 or 5, sparsely to densely dendritic. Cauline leaves short petiolate, similar to basal leaves in division and pubescence, reduced in size upward and becom- ing 3-lobed. Inflorescences few- to several-flowered, ebracteate corymbose raceme, elongated considerably in fruit; rachis strongly or rarely slightly flexuous or straight. Fruiting pedicels slender, sometimes thickened and nearly as wide as fruit, erect to divaricate. Sepals oblong, erect, base of inner pair not saccate, margin membranous. Petals white to lavender, distinctly longer than sepals; blade oblanceolate, apex obtuse; claw obscurely distinct from blade. Stamens 6, tetradynamous; filaments filiform; anthers broadly ovate, not apiculate. Nectar glands confluent and subtending bases of all stamens. Ovules (6-) 10-20 per ovary. Fruits dehiscent, linear, terete, torulose, divaricate to appressed to rachis, sessile; valves papery, veinless or with an obscure midvein; septum complete, membranous; style absent to obsolete; stigma capitate, entire. Seeds 2-8 per locule, uniseriate, wingless, oblong, plump; seed coat nearly smooth, not mucilaginous when wetted; cotyledons incumbent. Ianhedgea minutiflora (Hook.f. & Thomson) Al-Shehbaz & O'Kane, comb. nov. Basionym: Sisymbrium minutiflorum Hook.f. & Thomson, J. Linn. Soc, Bot. 5: 158 (1861). Lectotype (here designated): western Tibet, Prov. Zanskar, T. Thomson s.n. (K!). IANHEDGIA (BRASSICEAE), A NEW GENERIC NAME 323 Microsisymbrium minutiflorum (Hook.f. & Thomson) O.E. Schulz var. dasycarpum O.E. Schulz, Pflanzenreich IV. 105 (Heft 86): 161 (1924). Type: Afghanistan, Erak, Griffith 1390 (holo. B!; iso. K!, W!). Herbs (2-)4-20(-30)cm tall, sparsely to moderately pubescent with finely branched trichomes to 0.1mm long. Stems slender, branched above or rarely simple; branches filiform. Basal and lowermost cauline leaves with 1 or 2 pairs of lateral lobes; peti- ole 5-12mm long; lobes linear, filiform, narrowly oblong, to oblanceolate-linear, (l-)3-9(-12)mm long, 0.2-0.8(-1.3)mm wide, margin entire or very rarely obtusely 1-toothed, apex obtuse. Upper and middle cauline leaves 3-lobed, similar to lowermost leaves, always 3-lobed. Infructescence axis strongly flexuous, rarely straight or slightly fiexuous. Fruiting pedicels (0.5-)3-8(-12)mm long, slender or thickened, narrower or rarely nearly as wide as fruit, erect to divaricate, straight or slightly curved. Sepals oblong, (0.6-)0.8-l(-1.2)mm long, 0.4-0.5mm wide. Petals white to lavender, (0.9-)l.l-1.5(-1.8)mm long, O.3-O.5mm wide, oblanceolate, apex obtuse. Filaments white, 0.8-1.lmm long; anthers broadly ovate, c.0.2mm long. Fruit (0.4-)0.7-1.8(-2.5)cm long, 0.5-0.8mm wide; valves glabrous or sparsely pub- escent; style absent to obsolete, rarely to 0.1mm long. Seeds brown, oblong, 0.9-1.l(-1.2)mm long, 0.4-0.5(-0.6)mm wide. Fl. May-Aug, fr. June-Aug. lanhedgea minutiflora grows on limestone, marble outcrops, and scree slopes at altitudes of 2600 -4200m in Afghanistan, China, India, Iran, Pakistan, and Tajikistan. The species is highly variable in the density of indumentum, degree to which the infructescence rachis is flexuous, length, orientation, and thickness of fruiting pedi- cels, fruit length, number of seeds per locule, plant height, and stem branching. Except for the fruiting pedicels and infructescence rachis, however, the variation in all other characters is continuous in nature and does not appear to have any taxo- nomic significance. On the basis of length, orientation, and thickness of fruiting pedicels, as well as the degree at which the infructescence rachis is flexuous, the species can be easily divided into the following well-defined subspecies. Key to subspecies la. Fruiting pedicels divaricate, slender, distinctly narrower than fruit, (2.5-)4-9(-12)mm long; infructescence axis strongly flexuous subsp. minutiflora lb. Fruiting pedicels erect to ascending, rarely divaricate, stout and nearly as thick as fruit, 0.5-1.5 (-3) mm long, infructescence axis straight or slightly flexuous subsp. brevipedicellata lanhedgea minutiflora subsp. minutiflora Distribution. Afghanistan, China, India, Iran, Pakistan, and Tajikistan. 324 I. A. AL-SHEHBAZ & S. L. O'KANE Specimens examined. AFGHANISTAN. Prov. Badakhshan: W of Anjuman Pass, Podlech 12417 (M). Prov. Bamian: Band-i-Amir, Kohe Jak Ruya, Dieterle 1225 (G, M), Dieterle 1099 (G, M); Shibar Pass, Koh-i-Baba Mts., Furse 6651 (K, LE); Koh-i-Baba Mts, Gilli 986 (W); Koh-i-Baba, Darrah Bod Chur, SW of Bamian, Breckle 2618 (M); Bei Baraki Nawor, Neubauer 12 (W). Prov. Deh Kundi: Khonak, Rechinger 36652 (W). Prov. Ghazni: Dasht- i-Nawar, Breckle 1921a (M); Dasht-i-Nawar, Saperlebuli, Rechinger 37352 (B, M, W); Dasht- i-Nawar, NW Ghazni, Kasg 59 (W); Kadjicak Pass, Palmer 76 (K, W). Prov. Jaji: between Qasim Khel and Dobandi, Rechinger 32349 (W). Prov. Kabul: Qala-e Wazier, between Sar- i Chashma and Unai, Rechinger 18101 (W); Unai, Rechinger 36030 (B, E, G, LE, M, W, Z); Unai, Kuh-i- Qhalandaran, Hedge & Wendelbo 4509 (E, LE); Salang, Rechinger 31430 (W), Rechinger 37479 (G, M, W); Farakulum, Koie 2563 (W). Prov. Kunar: Bashgal-Quelltaler, Darrah-i-Pushal, Podlech 16424 (G, LE, M, W); Pushal-Tal, Moh. Rasoul 3541 (E, W). Prov. Maidan: Maidan-Tal, Unai-Kotal, Breckle 2271 (M); Unai Pass, Furse 8598 (K), Gilli 985 (W), Neubauer 513, 525 (W), Volk 1629 (W). CHINA. Tibet (Xizang): Zanskar, Thomson s.n. (K). INDIA. Lahul: near Kyelang, about Baralacha Pass, Stewart 430a (NY); without locality, Thomson s.n. (K, P, W). IRAN. Qashqai: Kohruyeh 25-36km, between Shahreza and Semirom, Rechinger 47333 (W). Elburz: Talyhan, Klein 3005 (W). Fars: Dena-Sicani Pass, Behboudi988E (W). [Tehran]: M. Tuchal (as Totschal), J. & A. Bommuller 6159 (B, E, G, K, LE, P, W). PAKISTAN. Chitral: Barum Gol, above Shokor Shal, 18 vi 1950, Wendelbo s.n. (BM). TAJIKISTAN. Pamir: Badakhshan, vicinity of Khorag, 21 vi 1966, Kamelin s.n. (LE); same area, 24 vi 1966, Kamelin s.n. (LE); Badakhshan, Andarob valley of river Garm-Chazma, near Zevdz, Sultanov 1215 (LE); Badakhshan, Alay, Khargugi Pass, Lukanenkova 189 (LE). Ianhedgea minutiflora subsp. brevipedicellata (Hedge) Al-Shehbaz & O'Kane, stat. et comb. nov. Basionym: Microsisymbrium minutiflorum (Hook.f. & Thomson) O.E. Schulz var. brevipedicellatum Hedge in Hedge and K. H. Rechinger, Fl. Iranica 57: 319 (1968). Type: Afghanistan, Bamian, W Panjao, Kotal-e Nalgis, 3100m, Hedge & Wendelbo 4957 (holo. E!; iso. BG). Microsisymbrium murgabicum Ikonn., Opred. Vyssh. Badakhshana 180 (1979). Syn. nov. Type: Tajikistan, Pamir, Badachshan, 3700m, 10 vii 1958, Y. Gusev 5233 (holo. LE!). Distribution. N. Afghanistan and adjacent Tajikistan. Specimens examined. AFGHANISTAN. Prov. Bamian: Band-i Amir, Rechinger 18382 (W); between Unai and Hajigak, Hedge & Wendelbo 4594 (E). Prov. Panjao: 12km E of Panjao, Rechinger 36196 (B, G, M, W). Prov. Ghour, E of Laal Sar Jangal, Hedge & Wendelbo 8755(K). Prov. Lugar, Ekberg 9166(E). TAJIKISTAN. Pamir: Badachshan, Gusev 5233 (LE). The monotypic Ianhedgea is most closely related to Neotorularia Hedge & J. Leonard, which it resembles in having linear, terete, torulose fruits, valves pubescent with branched trichomes, uniseriate, non-mucilaginous seeds, and incumbent cotyledons; however, it consists of very slender annuals with finely pinnatisect or trisect leaves, flexuous infructescence, few- to several-seeded fruits, dendritic trichomes, and con- fluent nectar glands. In contrast, Neotorularia includes coarse to robust annuals with IANHEDGIA (BRASSICEAE), A NEW GENERIC NAME 325 variously divided but never finely pinnatisect or trisect leaves, nonflexuous infruc- tescences, many-seeded fruits, often a mixture of simple and forked but never den- dritic trichomes, and nonco-fluent lateral glands without median nectaries. Ianhedgea is somewhat similar to Descurainia which it resembles in having pinnatisect leaves and dendritic trichomes, but the latter has 2- or 3-pinnatisect leaves, mucilaginous seeds, and often unicellular glandular trichomes. Ianhedgea has 1-pinnatisect or tri- sect leaves, non-mucilaginous seeds, and eglandular trichomes. Ianhedgea also resembles the monotypic Dichasianthus Ovcz. & Junussov in con- sisting of slender small annuals with minute flowers and flexuous infructescences; however, it has dendritic trichomes, terete fruits, and white to lavender flowers, whereas Dichasianthus has puberulent, simple trichomes, flattened fruits, and blue flowers. Blue flowers are very rare in the Brassicaceae and found in only a few genera, including the south African Heliophila L. and the Chinese Solmslaubachia Muschl. The superficial similarity between Ianhedgea and Dichasianthus is so remarkable that one collection, Rechinger 31976 (W), of D. subtilissimus (Popov) Ovcz. & Junussov was cited by Hedge (1968) as Microsisymbrium minutiflorum (=/. minutiflora). This collection represents the first record of Dichasianthus from Afghanistan. Dichasianthus subtilissimus is previously known to be endemic to Tajikistan. The limits of Dichasianthus were expanded by Sojak (1982) to include plants now assigned to Neotorularia, but this action is unwarranted because Neotorularia clearly differs by having terete, torulose, pubescent fruits, white to lavender flowers, and branched trichomes, whereas Dichasianthus has flattened, glabrous, smooth fruits, blue flowers, and simple trichomes. GENERIC ASSIGNMENTS OF SPECIES PREVIOUSLY PLACED IN MICROSISYMBRIUM Microsisymbrium angustifolium Jafri, Notes Roy. Bot. Gard. Edinburgh 22: 113 (1956) = Crucihimalya wallichii (Hook.f. & Thomson) Al-Shehbaz, O'Kane & Price, Novon 9: 301 (1999). M. axillare (Hook.f. & Thomson) O.E. Schulz, Pflanzenreich IV. 105 (Heft 86): 160 (1924) = Crucihimalya axillaris (Hook.f. & Thomson) Al-Shehbaz, O'Kane & Price, Novon 9: 301 (1999). M. bracteosum Jafri, Notes Roy. Bot. Gard. Edinburgh 22: 112 (1956) = Crucihimalya axillaris (Hook.f. & Thomson) Al-Shehbaz, O'Kane & Price, Novon 9: 301 (1999). M. duthiei O.E. Schulz, Notizbl. Bot. Gart. Berlin-Dahlem 9: 1089 (1927) = Crucihimalya lasiocarpa (Hook.f. & Thomson) Al-Shehbaz, O'Kane & Price 9: 300(1999). M.flaccidum O.E. Schulz, Notizbl. Bot. Gart. Berlin-Dahlem 9: 1090 (1927) = Arabis sp. but too immature for a definite determination. 326 I. A. AL-SHEHBAZ & S. L. O'KANE M. griffithianum (Boiss.) O.E. Schulz, Pflanzenreich IV. 105 (Heft 86): 161 (1924) = Olimarabidopsis pumlia (Stephan) Al-Shehbaz, O'Kane & Price Novon 9: 300 (1999). M. lasiophyllum (Hook. & Arn.) O.E. Schulz, Pflanzenreich IV. 105 (Heft 86): 162 (1924) = Caulanthus lasiophyllus (Hook. & Arn.) Payson, Ann. Missouri Bot. Gard. 9: 303 (1923). M. minutiflorum (Hook.f. & Thomson) O.E. Schulz, Pflanzenreich IV. 105 (Heft 86): 160 (1924) = lanhedgea minutiflora (Hook.f & Thomson) Al-Shehbaz & O'Kane. M. murgabicum Ikonn., Opred. Vyssh. Badakhshana 180 (1979) = Ianhedgea minuti- flora (Hook.f. & Thomson) Al-Shehbaz & O'Kane subsp. brevipedicellata (Hedge) Al-Shehbaz & O'Kane. M. pulchellum Rech.f. & Koeie, Anz. Math.-Nat. Kl. Osterr. Akad. Wiss. 7: 6 (1954) = Neotorularia aculeolata (Boiss.) Hedge & J. Leonard, Bull. Jard. Bot. Nat. Belg. 56: 393 (1986). M. qingshuiheense Ma & Z.Y. Zhu, Acta Sci. Nat. Univ. Intramongoli. 20: 538 (1989) = Neotorularia qingshuiheense (Ma & Z.Y. Zhu) Al-Shehbaz, O'Kane & G. Yang, comb. nov. Type: China. Nei Mongol. Ulanqab Meng, Qinshuihe, Jicia Zhang, 16 vii 1988, Z. Y. Zhu 88-003 (holo. HIMC). In all aspects of trichomes, leaves, fruits, and habit, Neotorularia qingshuiheense is perfectly at home in Neotorularia. The slightly flexuous inflorescence is unusual in Neotorularia, but this feature alone does not justify the inclusion of the species in Ianhedgea, and plants of the rather rare /. minutiflora subsp. brevipedicellata usually do not have typically flexuous infructescences. M. taxkorganicum Z.X. An, Fl. Xinjian. 2(2): 380 (1995)= Sisymbriopsis mollipila (Maxim.) Botsch., Not. Syst. PI. Vase. 3: 122 (1966). M. yechengnicum C.Z. An, Bull. Bot. Res. North-East Forest Inst. 1(1-2): 99 (1981) = Sisymbriopsis yechengnica (C.Z. An) Al-Shehbaz, Z.X. An, & G. Yang, Novon 9: 312(1999). ACKNOWLEDGEMENTS Field work in Europe and Asia was supported by the National Science Foundation grant DEB-9208433 and the National Geographic Society grant 5068-93, both of which were awarded to Al-Shehbaz and for which he is very grateful. Tatiana Shulkina is thanked for her translation of some of the Russian literature. REFERENCES AL-SHEHBAZ, I. A. (1973). The biosystematics of the genus Thelypodium (Cruciferae). Contr. Gray Herb. 204: 3-148. AL-SHEHBAZ, I. A. (1985). The genera of Thelypodieae (Cruciferae; Brassicaceae) in the southeastern United States. J. Arnold Arbor. 66: 95-111. IANHEDGIA (BRASS1CEAE), A NEW GENERIC NAME 327 BONNET, S. S. R. (1983). Eleven new combinations and one new name for flowering plants. J. Econ. Taxon. Bot. 4: 591-593. BUCK, R. E. (1995). Systematics of Caulanthus (Brassicaceae). 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