New Taxa and New Combinations in Hawaiian Bidens (Asteraceae)
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LYONIA Occasional Papers of the Harold L. Lyon Arboretum Volume 2, Nos. 1, 2, & 3 November 1983 Volume 2, No.1 -------------------------- Pages 1-16 NEW TAXA AND NEW COMBINATIONS IN HAWAIIAN BIDENS (ASTERACEAE) FRED R. GANDERS and KENNETH M. NAGATA Volume 2, No.2 Pages 17-21 A NEW SUBSPECIES OF BIDENS (ASTERACEAE) FROM MAUl HAROLD ST. JOHN,KENNETH M. NAGATA, and FRED R. GANDERS Volume 2, No.3 ------------------------- Pages 23-31 RELATIONSHIPS AND FLORAL BIOLOGY OF BIDENS COSMOIDES (ASTERACEAE) FRED R. GANDERS and KENNETH M. NAGATA LYONIA Occasional Papers of the Harold L. Lyon Arboretum Volume 2, NO.1 November 1983 NEW TAXA AND NEW COMBINATIONS IN HAWAIIAN BIDENS (ASTERACEAE) t FRED R. GANDERS' and KENNETH M. NAGATA' ABSTRACT. Bidens sandvicensis ssp. confusa Nagata & Ganders, B. hillebrandiana ssp. po/ycephala Nagata & Ganders, B. micrantha ssp. kalealaha Nagata & Ganders, and B. forbesii ssp. kahiliensis Ganders & Nagata are described as new. Bidens campylotheca ssp. pentamera (SherfO Ganders & Nagata, B. menziesii ssp. jilijormis (SherfO Ganders & Nagata, and B. micrantha ssp. ctenophylla (SherfO Nagata & Ganders are published as new combinations at subspecific rank. A key to all taxa of Bidens in the Hawaiian Islands is provided. In the course ofour investigation of the genetics of adaptive radiation and evolution of Bidens in the Hawaiian Islands, it has been necessary to revise the group taxonomically. Here we describe four new subspecies and make three new combinations at the rank of subspecies. It will be useful to have valid names published for use in other papers before our monograph is pub lished. We have also included a key to all taxa of Bidens in the Hawaiian Islands. Presently available keys to the Hawaiian taxa do not work, and include many species unworthy of any taxonomic recognition. Our key should be useful to ecologists or others who may need to identify Bidens in Hawai'i. It includes introduced taxa that have been collected in the islands in the last 80 years. Bidens laevis is excluded. It was collected several times before 1900, but probably does not persist on the islands. 'We thank Robert Hobdy, Bea Krauss, Ronald Nagata, and Steve Perlman for collections of seeds or cullings, Dr. Helen Kennedy for the Latin diagnoses, Lesley Bohm for the drawings, the Natural Sciences and Engineering Research Council ofCanada for financial support, and the cura tors at BISH, BM, F, G, GH, and HAW for loan of specimens. 'Department of Botany, University of British Columbia, Vancouver, B.C., Canada V6T 2Bl. "Harold L. Lyon Arboretum, 3860 Manoa Road, Honolulu, HI 96822. Library of Congress Catalog Card Number: 74·620038 Published by the Harold L. Lyon Arboretum, 3860 Manoa Road, Honolulu, Hawaii 96822 Date of Publication of Volume 2(1): I November 1983 2 LYONIA Vol. 2, No.1 Bidens sandvicensis Less. ssp. confusa Nagata & Ganders, ssp. nov. FIGURE 1. Differt a ssp. sandvicensis folioliis angustioris, minus quam 8 mm latis; flosculis radiatis 5-6, 05-)18-2l(-28) mm longis et (5-)6-9 mm latis. Erect to somewhat straggling perennial, 0.5-1.0 m tall, flowering ter minally as well as laterally, lateral branches ascending to nearly horizontal. Leaves pinnately or occasionally bipinnately compound, mostly 50-160 mm long including petiole; leaflets 5-9 to bipinnate, serrate, glabrous or glabr ate, mostly 15-80 mm long and less than 8 mm wide, more than 5 times as long as wide. Inflorescence a compound dichasium, rather diffuse, with 6 to more than 30 heads, peduncles of heads glabrous or sparsely pubescent, 00-)15-50 mm long. Heads 25-40 mm in diameter, outer involucral bracts (2.5-)3-4(-5) mm long. Ray flowers sterile, 5-6, yellow, 05-)18-21 mm long, (5-)6-9 mm wide. Disk flowers 17-22, perfect or pistillate, some populations gynodioecious. Achenes straight, black, wingless, setose on the margins and sometimes on the faces, 5-10 mm long and 0.75-1.0 mm wide; awns 2, 1-2 mm long, or absent. HOLOTYPE: Hawaiian Islands, Kauai, Waimea District, Kokee, along Waimea Canyon Road near Canyon Lookout, elevation about 3300'; 5 June 1982, K. Nagata 2473 (BISH). DISTRIBUTION: Restricted to the Koke'e region of Kaua'i, on west rim of Waimea Canyon from about 700-1100 m elevation. SPECIMENS EXAMINED: KAVA'I: near power house, Waimea Canyon, Degener et al. 23,981 (BISH); Kukui Trail, Waimea Canyon, Degener et al. 27,189 (BISH); near rim of Waimea Canyon, Gillett 1888 (HLA); Waimea Canyon rim, Hobdy 38 (BISH); Iliau Nature Trail, Hobdy 54 (BISH); Waimea Canyon Road, K. Nagata 1946-1948 (HLA). This taxon is common along the west rim of Waimea Canyon at about 1000 m elevation. It is not always easy to distinguish Bidens sandvicensis ssp. con/usa from ssp. sandvicensis morphologically, since it differs mainly in having larger ray flowers and heads and narrower leaflets. Some specimens have nearly linear leaflets but others approach those of some plants of ssp. sandvicensis. The two taxa retain their differences when cultivated in the same environment, and differ in polyacetylene chemistry (Marchant et al., in press) and in flavonoid chemistry (McCormick and Ganders, unpub lished). Subspecies sandvicensis also occurs on Kaua'i, but is usually restricted to elevations below 400 m. It is possible, however, that some intergradation occurs on the walls of Waimea Canyon. Gillett and Lim (970) and Gillett (975) considered this taxon to repre sent a natural hybrid between Bidens menziesii and B. /orbesii, largely on the basis of the finely divided leaves of the specimens Gillett had in cultivation. Bidens menziesii does not occur on Kaua'i, and ssp. conjUsa shows little resemblance to B. /orbesii. It is more similar to B. cervicata, which does occur nearby, but there is no evidence at present that it has hybridized with that taxon. The achenes of ssp. con/usa are identical to those of ssp. 1983 GANDERS & NAGATA: NEW HAWAIIAN BIDENS 3 ........a-..." A 2cm L.-..I B 1cm FIGURE 1. Bidens sandvicensisssp. confusa (A) terminal inflorescence; (B) flowering head show ing outer involucral bracts; (C) achene. 4 LYONIA Vol. 2, No.1 sandvicensis, and the narrow leaflets typical of ssp. con/usa are found on occasional plants of ssp. sandvicensis from O'ahu. Bidens hillebrandiana (Drake) Deg. ex Sherff ssp. polycephala Nagata & Ganders, ssp. nov. FIGURE 2. Campylotheca ruti/olia H. Lev. Repert. Spec. Nov. Regni Veg. 10: 123. 1911. LECTOTYPE (here designated): Hawaiian Islands, Molokai, Wailau, June 1910, U. Faurie 931 (BM!; isolectotype: P). Differt a ssp. hillebrandiana inflorescentiae cum capitulis 4-30, pedun culus capitulorum 2-12(-20) mm longis. Decumbent perennial herb, woody at base, less than 0.5 m tall, flowering terminally as well as on lateral branches. Leaves rarely simple, usually pin nately or bipinnately compound, mostly 35-80(-110) mm long including petiole; leaflets mostly 5-25 mm long and 2-15 mm wide, fleshy, crenately toothed or lobed, glabrous or sparsely pubescent. Inflorescence a compound dichasium; heads (4-)5-30, peduncles of heads glabrous or sparsely pubes cent, 2-12(-20) mm long. Heads 04-)19-24 mm in diameter, outer involucral bracts 2-3 mm long, inner involucral bracts short, often not covering flower buds. Ray flowers sterile, 5-6, yellow, 9-12 mm long, 3-4 mm wide. Disk flowers 11-21, perfect. Achenes straight, grayish black, wingless, setose on margins and often also on the faces, 6-8 mm long and 0.8-1.2 mm wide; awns 1-2 mm long, prominently retrorsely barbed. HOLOTYPE: Hawaiian Islands, East Maui, on ledge of sea cliffs with Sesuvium, Digitaria, and Lycium, west end of Maliko Bay, Makawao District, elevation 80',5 June 1979, K. Nagata 1897 (BISH). DISTRIBUTION: Windward coasts of East Maui and Moloka'i, on coastal bluffs or talus exposed to ocean spray, from sea level to about 60 m eleva tion. On Maui it occurs from Maliko Bay east to Hana and around the east end of the island to the mouth of the Kipahulu Valley. On Moloka'i it occurs on sea cliffs from Wailau Valley to Kikipua Point. SPECIMENS EXAMINED: MAUl: north shore of Kauiki Head, Hana, Degener et al. 12,397 (BISH); Oheo Stream, Kipahulu Valley, Higashino 5740 (BISH); Maliko Bay, K. Nagata 1894 & 1895 (HLA); Maliko Bay, K. Nagata 1896 (HLA). MOLOKA'I: Wailau Valley, talus slope at foot of cliffs, Fosberg 9666 (BISH, F); Kikipua Pt., Jacobi 1724 (BISH). The holotype of Bidens hillebrandiana is from the island of Hawai'i and has heads solitary on long peduncles, or rarely inflorescences of 2-4 heads on long peduncles. Subspecies hillebrandiana is known only from the wind ward Kohala coast and has been only rarely collected. The plants resemble hybrids of B. hillebrandiana ssp. po/ycephala and B. mauiensis, and some 1983 GANDERS & NAGATA: NEW HAWAIIAN BIDENS 5 ~ 2cm FIGURE 2. Bidens hillebrandiana ssp. polycephala (A) terminal inflorescence; (B) achenes; (C) flowering head showing outer involucral bracts; (D) stem leaf. 6 LYONIA Vol. 2, No.1 specimens at BISH were annotated as such by Gillett. Subspecies hillebran diana is reasonably constant and the achenes show no evidence of hybridization with B. mauiensis, which does not occur on the island of Hawai'i in any case. Bidens hillebrandiana is more common on east Maui and Moloka'i, but plants from these islands have branching inflorescences and heads on short peduncles. They are best considered a distinct subspecies. In describing Campylotheca ruti/olia Leveille cited two numbers, Faurie 931 and 965. Faurie 931 is from Moloka'i and is here designated as the lec totype. It is a synonym of B. hillebrandiana ssp.