Bidens wichmanii W.L. Wagner, J.R. Clark & Lorence, 2014

Wagner, Warren L., Clark, John R. & Lorence, David H., 2014, Revision of endemic Marquesas Islands Bidens (Asteraceae, Coreopsideae), PhytoKeys 38, pp. 37-67 : 52-53

7. Bidens wichmanii W.L. Wagner, J.R. Clark & Lorence sp. nov. Figure 9

Type.

Marquesas Islands. Fatu Hiva: Tevaiua, southern summit region, 870 m, 15 Feb 2003, K. R. Wood 10140 (holotype: PTBG-043994; isotypes: AD, BISH, K, MO, MPU, NY, P, PAP, US).

Description.

Scandent to ascending suffrutescent perennial herbs 0.5-2 m tall. Leaves simple, 3.5-13.5 cm long including petiole, blades lanceolate to elliptic-lanceolate, 2.3-9.5 × 1.2-4.5 cm, glabrous, margins serrate, apex acute. Heads 1-3, in diffuse cymes terminating main stem and lateral branches, 8-15 mm in diameter excluding rays, peduncles (2-)3.5-14 cm long, glabrous; outer involucral bracts 8-12 mm long, broad, well differentiated from inner bracts; ray florets 14-20+ per head, sterile, rays yellow, 10-18 × 3-4 mm; disk florets ca. 50, perfect, corollas yellow. Achenes black, straight, 7-10 × 1-2 mm, slightly keeled, glabrous; pappus of 2 irregular antrorse barbed awns.

Distribution.

Marquesas Islands, known only from the central summit region of Fatu Hiva (Tevaiua, Hanativa, and Tekau), 670-870 m.

Habitat.

Occurs in shrubland of Metrosideros collina with Freycinetia impavida, Crossostylis biflora , and Dicranopteris linearis , on the windswept summit or near-summit areas.

Etymology.

This new species is named for Charles R. “Chipper” Wichman, Jr., Chief Executive Officer and Director of the National Tropical Botanical Garden since 2005, and previously Director of NTBG’s Limahuli Garden on Kaua`i since 1994.

Conservation status.

Proposed IUCN Red List Category Critically Endangered (CR), criteria B1ab, B2a,b (i-iii): B1, total extent of occurrence less than 100 km² (less than 10 km²); a,b, known from a single location; B2a, area of occupancy estimated to be less than 10 km²; B2b (i-iii), habitat continuing decline inferred. The estimated area of occupancy for Bidens wichmanii on Fatu Hiva (ca. 85 km²) is indicated as an endangered environment, threatened by human activity (deforestation and fire), feral animals, and invasive plant species, thus reducing the extent of the suitable habitat.

S

pecimens examined.

Marquesas Islands. Fatu Hiva: Along trail between Omo’a and Uia within 1 km from pass over central ridge, 750 m, 12 Oct 1974, Decker 2397 (BISH, P, NSW, US); Sentier d’Ouia vers Omoa, crête au-dessus de la vallée d’Ouia, S du col de Teava, 680 m, 23 Sep 1975, Schäfer 5843 (MPU[7], PTBG, US); Omoa Valley, past Hoopu to ridge near Tevaiua, top of ridge, 2200 ft [671 m], 22 Jul 1988, Perlman 10152 (BISH, PAP, US); north of Hanativa Valley along ridge crest approaching summit area, 800-900 m, 23 Oct 1974, Decker 2626 (BISH, MO, PTBG, US); along summit crest of ridge above Omoa valley, south of Tekau peak, north of Tevaiua, 760 m, 10°31"10.6'S/138°38"8'W, 15 Feb 2003, Perlman 18453 (PTBG, US); Tevaiua, southern summit region, 870 m, 15 Feb 2003, Wood 10138 (PTBG, US), Wood 10139 (PTBG) [used in molecular study, Funk et al.].

Discussion.

Bidens wichmanii has the largest heads among the Marquesan species. The glabrous achenes are also distinctive in being keeled along the long axis.

Figures

Figure 9. Bidens wichmanii W. L. Wagner, J. R. Clark & Lorence A Distal part of plant B Head showing rays and involucral bracts (outer series) C Head post-flowering showing involucral bract D Inner involucral bract E Ray corolla F-G Disk corolla H Disk corolla longitudinal section I Achene. Drawn from Wood 10140 (isotype, US) [A, C, I], and Perlman 10152 (US) [B, D-G, H].