Bidens polycephala Sch. Bip., Flora 39: 360. 1856.

Wagner, Warren L., Clark, John R. & Lorence, David H., 2014, Revision of endemic Marquesas Islands Bidens (Asteraceae, Coreopsideae), PhytoKeys 38, pp. 37-67 : 44-46

2. Bidens polycephala Sch. Bip., Flora 39: 360. 1856. Figure 3E-F

Coreopsis polycephala (Sch. Bip.) Drake, Ill. Fl. Ins. Mar. Pac. 209. 1890. Type. Marquesas Islands. Nuku Hiva, D.E.S.A. Jardin 40 (holotype: P).

Bidens jardinii Sch. Bip., Flora 39: 360. 1856.

Coreopsis jardinii (Sch. Bip.) Drake, Ill. Fl. Ins. Mar. Pac. 209. 1890. Type. Marquesas Islands. Nuku Hiva, D.E.S.A. Jardin 41 (holotype: P).

Bidens ahnnei Sherff, Bot. Gaz. (Crawfordsville) 76: 165. 1923. Type. Marquesas Islands. Nuku Hiva, Hakaui, December 1916, C. Henry s.n. (holotype: F [452364]!; isotype: F!).

Bidens collina Deg. & Sherff, Bot. Gaz. (Crawfordsville) 96: 144. 1934; Publ. Field Mus. Nat. Hist., Bot. Ser. 16: 79. 1937.

Campylotheca collina (Deg. & Sherff) F. Brown, Bernice P. Bishop Mus. Bull. 130: 354. 1935. Type. Marquesas Islands. Hiva Oa: Tehutu, 100 m, 19 May 1929, E.P. Mumford & A.M. Adamson 400 (holotype: NY-00162622!; isotype: BISH!).

Description.

Erect subshrubs 0.5-2 m tall. Leaves simple or very rarely (Nuku Hiva) compound and trifoliolate, 3-15.5 cm long including petiole, blades lanceolate to elliptic-lanceolate, 2-11 × 1.2-5 cm, glabrous or lower surface occasionally pubescent, especially on young leaves, margins variably serrate to serrulate or subentire, apex acuminate or occasionally acute or caudate (Nuku Hiva). Heads 10-80(-100+), glabrous to sparsely pubescent at base, in diffuse cymes terminating main stem and lateral branches, main inflorescence axis up to 6.5 cm, heads 2-5 mm in diameter excluding rays, peduncles 0.1-5 cm long, glabrous or sparsely pubescent; outer involucral bracts 1-4.5 mm long, well differentiated from inner bracts, glabrous to sparsely ciliate; ray florets 3-12 per head, sterile, rays yellow, 3-12 × 1-4 mm, apex rounded, entire or bi- or tri-lobed; disk florets ca. 12-25, perfect. Achenes gray to black, straight or slightly curved, 3-8 × 0.5-1 mm, margin setose; pappus of 0-2 short awns. n = 36 (Gillett 1972).

Distribution.

Marquesas Islands, occurring on Nuku Hiva, Ua Huka, Hiva Oa, Mohotani, and Tahuata, 10-800(-1080) m. The occurrence on Mohotani is based on observation by Jean-François Butaud (pers. comm., 2014), but should be verified by collections.

Habitat.

Bidens polycephla is known from slopes and ridges to windswept cliffs, in mesic forests with Freycinetia impavida (Gaudich. ex Hombr.) B. C. Stone, Metrosideros collina , and Dicranopteris linearis (Burm. f.) Underw., or Hibiscus tiliaceus L. and Pandanus tectorius Parkinson ex Du Roi forest.

Conservation status.

Proposed IUCN Red List Category Endangered (EN), criteria B2b i-iii): B2, total area of occupancy less than 500 km² (ca. 50 km²); b (i-iii), habitat continuing decline inferred. The suitable habitat for Bidens polycephla on Nuku Huka (ca. 340 km²), Ua Huka (ca. 83 km²), and Tahuata (ca. 61 km²) is indicated as an endangered environment, threatened by human activity (deforestation), feral animals, and invasive plants, thus reducing the extent of the forest. However, Bidens polycephala has been observed to be locally common in some areas with considerable regeneration, and alternatively it might be considered Near Threatened (NT) (Butaud, pers comm. 2014).

Specimens examined.

Marquesas Islands. Nuku Hiva: Hakaui, ridge, 800 m, 7 May 1921, Brown 405B (BISH); Between Taiohae Bay and Hooumi Bay, 900 m, 20 Jul 1977, Gagné 1155 (BISH, US), Gagné & Montgomery 1162 (BISH); Terre Deserte, Haatuatua Valley, 1050 m, 1 Aug 1988, Gagné & Montgomery 2463, 2471 (BISH); Route Toovii-Terre Deserte, km 4 après le col, 940 m, 8°50"S/140°10"W, 9 Dec 1982, Florence 4353 (BISH, K, NY, P, US); Route Toovii-Terre Deserte, km 1 après le col, 960 m, 8°52"S/ 140°10"W, 10 Dec 1982, Florence 4390 (BISH, P, PAP); Moyenne Taipivai, sous le captage de la cascade de Teuakueenui, 440 m, 8°51"S/140°6"W, 4 Aug 1987, Florence 8471 (BISH, P, PAP, US); Taipi Vai, 500 m, 7 May 1921, Brown 405A (BISH); Piste Aakapa-Pua, sous le col de Taahui, 260 m, 8°49"S/140°9"W, 7 Aug 1987, Florence 8502 (PAP), 180 m, 8502(PAP); Toovii, face SE du Mt. Tuhokia, 1080 m, 8°50"S/140°8"W, 10 Mar 1986, Florence 7516 (PAP); Moyenne vallée de Hakaui, secteur central, 240 m, 8°54"S/ 140°9"W, 23 Jul 1987, Florence 8387 (BISH, P, PAP); Hakaui Valley, 61 m, 26 Jun 1988, Perlman 10010 (BISH, PAP, PTBG); Toovii, épaulement au-dessus du réservoir, 1020 m, 8°52"S/140°9"W, 7 Dec 1982, Florence 4332 (BISH [2], K, NY, P, US); Route Toovii-Terre Deserte, 2 km après le col, 960 m, 8°52"S/140°10"W, 4 Jun 1984, Florence 6895 (BISH [2], P, PAP); South spur of the summit ridge of the island, between Hakui and the Tapuaooa shelter on the Toovii Plateau, 1070 m, 21 Jul 1970, Gillett 2194 (BISH, US); Mountain near Hakaui, s.d., Sherff 3090 (BISH); 22 Dec 1919, Sherff 3084-b (BISH [2]); 17 Sep 1919, Sherff 3084-a (BISH); Ridge, 800 m, 18 Oct 1922, Quayle 1588 (BISH); Partie S de Toovii, 750 m, 11 Jul 1975, Thibault 143 (BISH, P, US); Taipivai, Teuakueenui Falls area, 351 m, 8°51"2'S/140°6"10'W, 25 Jun 1997, Wood, Meyer & Luce 6356 (BISH, HAST, MO, NY, P, PAP, PTBG, UBC, US). Ua Huka: Ridgecrest south of central Vaipae’e Valley, approx. 2 km E of bend, 450 m, 18 Mar 1964, Decker 1877 (BISH, MO, PTBG, US); central crest of island N of Vaipae’e, 550-600 m, 16 Mar 1964, Decker 1868 (US); seacliffs just before the village of Hokatu, road from Hane to Hokatu, 12 m, 1 Jul 1997, Perlman, Wood & Meyer 15878 (MO, NY, P, PAP, PTBG, UBC, US, WU); Hitikau region, ascended via the Matukuoha Ridge over-looking Hane, constitutes the summit of the single crater of Ua Huka, 730 m, 5 Dec 2003, Wood 10495 (PTBG); Hane valley, ridge and cliffs above Tiki marae, back of valley on west side, 518 m, 8°54"50.6'S/138°31"51.5'W, 12 Jun 2004, Perlman, Lorence, Dunn & Wood 19009 (BISH, P, PAP, PTBG, US); Ridgecrest about 1 km N of Tahoatikikau crater, 300 m, 23 Mar 1964, Decker 1918 (BISH, CHR, K, MO, P, US); Hanahouua Valley, back of valley, cliffs near ridge between Hanahouua and Hanaei, 488 m, 8°54"46.7'S/139°30"8.68'W, 28 Jul 2005, Perlman & Meyer 19750 (BISH, MPU, NY, P, PAP, PTBG, US) [used in molecular study, Funk et al.]; Summit of Hitikau, crest of island, at very summit, 853 m, 28 Jun 1997, Perlman, Wood & Meyer 15847 (PTBG); Vaipaee, upper valley, Aunoa property, 60 m, 8°54"40'S/139°34"11'W, 9 Dec 2003, Wood 10504 (AD, BISH, BR, K, MO, NY, P, PAP, PTBG, US); Hokatu village coast, scattered along coast and cliffs from Hokatu to Tenaha to Haavahae, 31 m, 8°55"6.32'S/139°31"17.8'W, 10 Jun 2004, Perlman 19001 (BISH, P, PAP, PTBG, US); Hane/Hokatu cliff zone, 520 m, 11 Dec 2003, Wood & Meyer 10515 (BISH, P, PAP, PTBG, US); Hanahouua valley, back of valley below cliff walls, 1500 ft, 8°54"46.7'S/139°30"8.68'W, 26 Jun 2004, Perlman & Wood 19071 (BISH, P, PAP, NY, PTBG, US); Crest of ridge W of Vaipae’e Valley, approx. 3 km inland from bayhead, 280-300 m, 25 Feb 1964, Decker 1728 (BISH, MO, P, PTBG, US); Matukuoha, on ridge leading to Hitikau, 549 m, 28 Jun 1997, Perlman, Wood & Meyer 15857 (BISH, MO, NY, MPU, OS, P, PAP, PTBG, US). Tahuata: Near village of Hapatoni, coast to south of village, on seacliffs about.25-5 miles from Hapatoni, 46 m, 9°58"14.2'S/139°7"8.01'W, 3 Feb 2003, Perlman & Price 18376 (BISH, P, PAP, PTBG, US); Vaitahu, vers la crête d’Uuau, partie basse de la crête, 550 m, 8 Apr 1975, Schäfer 5468 (K, MPU, US); Base of cliff, above slope, about.3 km S. of Hapatoni, 150 m, 3 Feb 2003, Price 218 (BISH, P, PAP, PTBG, US) [used in molecular study, Funk et al.]; Trail from Vaitahu to Hapatoni, Tiana, the Vaitahu water catchment, 190 m, 30 Jan 1975, Oliver & Schäfer 3068 (BISH, CBG, CHR, K, MO, NSW, L, PTBG, US); Hanatetena, main valley, first deep side gulch to the north, 457 m, 2 Feb 2003, Wood 10081 (PTBG, US); Near village of Hapatoni, coast to south of village, on seacliffs about 0.25-5 miles from Hapatoni, 100 m, 9°58"23'S/139°7"8'W, 3 Feb 2003, Perlman & Price 18378 (BISH, NY, P, PAP, PTBG, US).

Discussion.

Bidens polycephala is the most variable of the Marquesan Bidens , and is also the most widespread, occurring on four islands. It is similar to Bidens henryi but differs in having much shorter involucral bracts and in the large but variable number of heads among individuals, and it occupies drier and lower elevation habitats. Some of the collections of this species from Nuku Hiva seem to grade toward Bidens bipontina as they have more caudate leaf apices and longer rays (e.g., Florence 4332, 4353, and 4390 from Toovii Plateau area) than collections from other areas of Nuku Hiva and other islands. Specimens from the Terre Deserte, Haatuatua Valley ( Gagné & Montgomery 2463, 2471) have heads on the smaller end of the variation like some other collections from Nuku Hiva, but uniformly have compound leaves. Compound leaves occurs only in Haatuatua and the adjacent Tapueahu Valleys, and they are found in all three of the species that occur there ( Bidens cordifolia , Bidens bipontina , and Bidens polycephala ). Otherwise these species all have simple leaves. The only exception to this is the rare occurrence of compound leaves in Bidens microcephala on Fatu Hiva. This pattern could be the result of presence of compound leaves in populations of one of the three species and hybridization among them at some time in the past. Two collections are considered putative hybrids and are discussed below. Gillett (1972) used a collection (Gillett 2194) in his experimental studies of Pacific Bidens . He determined that Bidens polycephala was self-compatible and is capable of forming fully fertile F1 hybrids with several Hawaiian species ( Bidens mauiensis (A. Gray) Sherff, Bidens menziesii (A. Gray) Sherff, and Bidens molokaiensis (Hillebr.) Sherff).

Figures

Figure 3. Bidens beckiana (F. Br.) Sherff (A-B). A Distal part of plant B Head post-flowering showing involucral bracts and apex of achenes. Drawn from Florence 9368 (US) [A] and Perlman 10064 (US) [B]. Bidens cordifolia Sch. Bip. (C-D). C Distal part of plant D Head post-flowering showing involucral bracts. Drawn from Wood & Perlman 4600 (US). Bidens polycephala Sch. Bip. (E-F). E Distal part of plant F Head post-flowering showing involucral bracts and apex of achenes. Drawn from Perlman 15878 (US). Image from field shots used to augment illustration of Wood 10504.