Difference between revisions of "Kadua nukuhivensis"

Latest revision as of 07:39, 13 July 2011

Taxonavigation

Ordo: Gentianales
Familia: Rubiaceae
Genus: Kadua

Name

Kadua nukuhivensis (Lorence & J. Florence) W.L.Wagner & Lorence, Syst. Bot. 30 : 832, 2005. – Wikispecies link – Pensoft Profile

• Hedyotis nukuhivensis J. Florence & Lorence (Adansonia sér. 3, 22: 224, 2000). [Basionym]

Type

Marquesas Islands: Nuku Hiva: route Toovii–Terre Déserte, 5 km après le col, 8°52'S, 140°10'W, 1020 m, 5 juin 1984, J. Florence 6914 (Holotype P!; Isotypes BISH!, P!, PAP!, PTBG!, US!).

Description

Glabrous shrubs or small trees 2.5–6 m tall, trunk to 20 cm in diam., leafy twigs cylindrical, 7–9 mm in diam., internodes compressed, bark grayish- to blackish-brown. Leaves of a pair equal to sometimes unequal, blade obovate to obovate elliptic or oblong, 8–18 × 6–10.5 cm, chartaceous to subcoriaceous, drying brown or blackish-brown, base cuneate, decurrent, apex obtuse to rounded, secondary veins 7–9 pairs, loosely brochidodromous, prominulous above, tertiary veins slightly prominulous, higher order venation obscure, midrib sulcate above, rounded below, margin entire, plane to slightly revolute; petioles 8–13 × 2–3 mm in diam., sulcate; stipules inter- and intrapetiolar, sheath truncate, cupuliform, 2.5–3 × 5–6 mm, caducous but becoming thickened and horseshoe-like on adaxial surface of petioles. Inflorescences terminal and rarely also axillary in upper leaf axils, cymose, corymbiform, 7–13 cm long including corollas, on a stout, compressed peduncle 3–6 cm long or sessile with a pair of basal branches, often subtended by a pair of reduced subsessile leaves, bracts foliaceous, 1.5–3 cm long, caducous. Flowers 12–30, possibly dimorphic, fragrant when fresh, subtended by caducous triangular bracts c. 1 mm long, hypanthium obconical, 3 mm long, calyx limb cupuliform, 2 mm long, calyx lobes broadly triangular, 0.3–0.5 mm long; corolla fleshy, white or pinkish white when fresh, apex flat to slightly depressed in bud, at anthesis salverform, tube 26–28 × 2 mm in diam. distally, lobes 4, linear-oblong, recurved, 10–15 × 3–5 mm, apex with a recurved hook-like appendage; stamens with anther tips exserted for 1.5 mm, mucronulate, linear, 3–4 × 1 mm, attached 1.5–2 mm below apex of tube; style 17–19 mm long, included, stigmatic lobes 2, adnate, 3 mm long. Capsules on stout pedicels to 6 mm long, turbinate to obpyriform, 15–25 × 7–14 mm, strongly compressed, bisulcate, strongly 8-ribbed, 2/3 inferior, apex (beak portion above the calyx) obtuse, 5–6 mm long, smooth, dehiscence loculicidal then septicidal, old capsules disintegrating leaving network of vascular bundles enclosing the persistent endocarp. Seeds 1–1.3 × 0.5–0.9 mm, irregularly angulate to broadly ellipsoid, trigonous, margins thin, testa dull, dark brown, surface finely papillose.

Distribution

Marquesas Islands, Nuku Hiva, where known only from the island's central mountain crest, on the leeward side of the Terre Déserte in the upper Tapuaehu Valley, between 1000 and 1065 m elevation.

Ecology

This species occurs in wet forest with species of Hernandia, Ilex, Metrosideros, and Weinmannia in the canopy and the understory with species of Cyrtandra, Melicope, and Psychotria. Numerous pteridophytes occur terrestrially and as epiphytes. Kadua nukuhivensis also occurs in shrubland on ridge crests with species of Alsophila, Bidens, Dicranopteris, Elaphoglossum, Freycinetia, Pennisetum, and Styphelia.

Etymology

The specific epithet refers to the only known island of occurrence for this species.

Conservation status

The suitable habitat for Kadua nukuhivensis on Nuku Hiva (c. 340 km2) is indicated as an endangered environment, threatened by human activity (deforestation and fire), feral animals, and invasive plants, thus reducing the extent of the forest. Based on the IUCN criteria and categories this species is assigned a preliminary Red List status of Endangered (EN): B1, B2b (i-iii): B1 extent of occurrence <5,000 km2; B2: total area of occupancy less than 500 km2 (c. 75 km2); B2b (i-iii), habitat continuing decline inferred in (i) extent of occurrence, (ii) areas of occupancy, and area, (iii) extent and/or quality of habitat. This status is a revision from VU originally suggested by Florence and Lorence (2000)^[1].

Specimens examined

Marquesas Islands: Nuku Hiva: Route Toovii—Terre Déserte, haute Tapuaehu, 8°52'S, 140°11'W, 1020 m, 14 fév 1986, Florence 7545 (BISH, P, PAP, US); off the old Airport road west of the summit crest of Peak #1227 m, drainages of Tapueahu Valley, 0.75 miles south of Airport Road, bottom of valley, 3340 ft., 24 sep 1995, Perlman15054 (AD, BISH, MO, P, PAP, PTBG (2), US); Ooumu area (sic), top of Tapueahu off new Hwy, 8°51'53"S, 140°10'63"W, 3500 ft, 23 jun 1997, Wood, Meyer & Luce 6337 (BISH, P, PAP, PTBG, US).

Discussion

Kadua nukuhivensis resembles Kadua tahuatensis, and molecular evidence places these two as sister species in the same clade within the larger clade of Hawaiian and French Polynesian species (Motley 2003^[2])

Taxon Treatment

• Wagner, W; Lorence, D; 2011: Revision of Kadua (Rubiaceae) in the Marquesas Islands, French Polynesia, with description of the new species K. lichtlei PhytoKeys, 4: 125-138. doi

Other References

1. ↑ Florence J, Lorence D (2000) Sertum polynesicum VI. Rubiaceae nouvelles des îles Marquises (Polynésie française) 2. Le genre Hedyotis. Adansonia, sér. 3, 22: 223–230.
2. ↑ Motley T (2003) Phylogeny of Hawaiian and Pacific Hedyotis (Rubiaceae): fruit evolution and the implications for conservation and genomics. Abstracts of Annual Meeting, Mobile, Alabama, Botany 2003, 88−89. http://www.2003.botanyconference.org/engine/search/detail.php?aid377

Images

Figure 2. Seeds of three Marquesan Kadua species, whole seed and surface detail A, B Kadua lichtlei, Wood 10514 (PTBG) C, D Kadua nukuhivensis C Perlman 15029 (PTBG) D Perlman 15054 (PTBG) E, F Kadua tahuatensis Perlman 16020 (PTBG).