Kadua lichtlei Lorence & W.L.Wagner, 2011

Wagner, Warren L. & Lorence, David H., 2011, Revision of Kadua (Rubiaceae) in the Marquesas Islands, French Polynesia, with description of the new species K. lichtlei, PhytoKeys 4, pp. 125-138 : 127-129

Kadua lichtlei Lorence & W.L.Wagner sp. nov. Figs. 1 2A,B 3

Latin.

Differt a congeneribus Marquesanis laminis late ovatis vel late ellipticis vel rotundis (3-) 5-17.5 × (1.8-) 3.5-11.5 cm, inflorescentia 6.5-14 × 9-12 cm, floribus in inflorescentibus 80-300, parvis, hypanthio 1-1.8 mm longo, corollae tubo 1.8-2.2 mm longo, corollae lobis 1.5-2 mm longis, et capsulis minoribus 4-5 × 3.5-4 mm.

Type.

Marquesas Islands: Ua Huka: Hane/Hokatu cliff zone, 520m elevation, 14 December 2003, K.R Wood and J.-Y. Meyer 10554 (holotype PTBG-44091!; Isotypes AD!, BISH!, BR!, K!, MO!, NY!, P!, PAP!, US!).

Description.

Shrub or small tree reaching 4 m tall, glabrous except for inflorescence, moderately branched, branches diffuse or often decumbent, twigs 3-3.5 mm in diam., internodes compressed,bark smooth to striate, dark brown. Leaves opposite, those of a pair at a node equal or sometimes unequal, blade (3-) 5-17.5 × (1.8-) 3.5-11.5 cm, broadlyovate, broadly elliptic, broadly obovate-elliptic or subcircular, chartaceous, glabrous, when fresh glossy dark green above, light green beneath, costa greenish white, margins entire, base acute to obtuse or rounded, shortly decurrent, apex obtuse or rounded, tip abruptly short acuminate, 0.5-1.5 cm, secondary veins 6 –9(– 11) per side, festooned brochidodromous, venation prominulous and conspicuous to 3° adaxially and to 4° abaxially; petioles (0.5 –)1– 2 cm long, winged distally; stipules interpetiolar (occasionally also intrapetiolar), fused with adaxial petiole bases, the body forming a short, broadly triangular sheath 1.5-3 × 3-7 mm, apiculate or with a short lateral ridge, glabrous, persistent. Inflorescences terminal, 6.5-14 × 9-12 cm (including the corollas), cymose-paniculate or -corymbiform, trichotomous, 80-300-flowered, sessile or sometimes with peduncle 3-4 cm long, the basal primary branches subtended by a pair of short petiolate, ovate foliaceous bracts 2-3.5 cm long, branching to the 4° (-5°), axes and pedicels minutely papillose-puberulent, subtended by brown triangular acuminate bracts 0.5-2 × 0.5-1 mm. Flowers hermaphroditic, apparently monomorphic and protandrous, borne in dichasial cymules on ultimate branches, central flower often sessile, lateral ones on pedicels to 4 mm long, hypanthium green when fresh, 1-1.8 × 1.2-1.6 mm, broadly obovoid or obconical, tuberculate, calyx tube 0.2-0.4 mm long, glabrous externally and internally, calyx lobes 4 (-5), 0.2-0.5 mm long, triangular, glabrous;corolla in bud 4-angular, apex obtuse, slightly or not depressed, at anthesis shortly hypocrateriform, when fresh with white lobes and green tube, tube 1.8-2.2 × 1-1.3 mm medially, externally and internally glabrous, lobes 4, triangular-ovate, 1.5-2 × 1.3-1.6 mm, apex with a small incurved appendage, externally papillose, internally rugulose; anthers 4, 0.7-1.4 mm long, ellipsoid, apiculate, bilobed basally, sessile, attached below top of tube, tips exserted; style 1.5 mm long, stigma lobes 0.5 mm long, included in tube. Capsules 2/3 inferior, broadly obovoid to subglobose, 4-5 × 3.5-4 mm in diam.,apex (beak portion above the calyx) rounded to conical, glabrous, dark brown when fresh, vascular bundles becoming visible with age, loculicidal, apex splitting into 4 segments. Seeds c. 200, dull brown, 0.5-0.6 × 0.35-0.4 mm, irregularly ovoid to ellipsoid, laterally compressed, laterally cuneate with a marginal punctiform hilum, the testa irregularly reticulate with areoles enclosing granulate-verrucose mounds.

Distribution.

This new species is known only from Ua Huka, Marquesas Islands, where it is apparently restricted to the Hokatu cliff zone above Hane village.

Ecology.

Rare and localized, this new species occurs in mixed wet shrubland and herbland growing on basalt cliffs and rock outcrops above wet forest of Hibiscus tiliaceus L., Pandanus tectorius Parkinson, and Freycinetia impavida (Gaudich. ex Hombr.) B.C. Stone. Other associates include species of Bidens , Boehmeria , Maytenus , Peperomia , Alyxia , Morinda , Phyllanthus , Miscanthus , Macropiper , Xylosma , and diverse pteridophytes. It was collected in flower in December and June (in bud), and in fruit in June and December (old fruit with a few seeds).

Etymology.

We are pleased to name this new species in honor of Mr. Léon Lichtle, Mayor of Ua Huka, for his generous help and logistic support when we conducted field work on the island and also in recognition of his strong support for conserving the island's native flora and fauna.

Conservation status.

The area of occupancy (distribution) for the species was calculated using herbarium collection data and field observations, and the conservation status is proposed following the IUCN Red List Category criteria ( IUCN 2001). IUCN Red List Category: Critically Endangered (CR): B2a, B2b i-iii; D: B2: total area of occupancy less than 10 km2 (ca. 5 km2). B2a, a single population known; b ( i–iii), habitat continuing decline inferred. The suitable habitat for Kadua lichtlei on Ua Huka (ca. 83 km2) is indicated as an endangered environment, threatened feral animals and invasive plants, reducing the extent of the forest. Estimated population size is about 30 individuals known only from the type locality (Wood & Meyer 10514). Threats include invasion by weeds including Psidium guajava L. and Ageratum conyzoides L., browsing by goats, and landslides. Several plants are in cultivation at the National Tropical Botanical Garden grown from seed (NTBG accession no. 040036, ex Wood 10514).

Specimens examined.

Marquesas Islands: Ua Huka: Hane valley, ridge and cliffs above tiki marae, back of valley on west side, 8°54.48'S, 138 °3.54'W, 518 m, 12 Jun 2004, Perlman et al. 19007 (BISH, P, PAP, PTBG, US); Hane/Hokatu cliff zone, 520m, 11 December 2003, Wood & Meyer 10514 (BISH, P, PAP, PTBG, US), 550m, 14 December 2003, Wood & Meyer 10544 (PTBG, US), 10547 (PTBG, US), 12 June 2004, 8°54.72'S, 139 °31.60'W, 520 m, Wood et al. 10737 (PTBG), 19738 (PTBG, US).

Cultivated.

Hawaiian Islands: Kaua`i: Koloa District, National Tropical Botanical Garden, horticulture center nursery, 5 October 2005, Lorence 9476 (PTBG, US).

Discussion.

Within the Marquesan clade Kadua lichtlei differs markedly from the other three species by a number of characters, notably its broadly elliptic to broadly ovate or subcircular leaf blades, much smaller and more numerous flowers (80-300 per inflorescence), and smaller capsules. In addition, seeds of Kadua nukuhivensis and Kadua tahuatensis (those of Kadua lucei were not available) are more sharply angulate with well defined marginal ridges. Seed morphology has proven useful in the infrageneric classification of Kadua ( Terrell et al. 2005). Seeds of Kadua lichtlei are laterally compressed and laterally cuneate with a marginal punctiform hilum, ovoid to ellipsoid, and irregularly angulate with an irregularly reticulate testa with areoles enclosing reticulate-verrucose mounds ( Fig. 1G , 2A,B ). Its seed morphology suggests an affinity to species of the Hawaiian Kadua sect. Kadua ( Terrell et al. 2005). However, we here place Kadua lichtlei in section Austrogouldia , partly based on the fact that the intra-areolar seed surface has reticulate verrucose sculpturing and is somewhat different from that in sect. Kadua . Seeds of species examined so far in this section ( Kadua nukuhivensis and Kadua tahuatensis ) link section Austrogouldia to the Hawaiian sect. Kadua .

Figures

Figure 1. Kadua lichtlei Lorence & WL Wagner A habit, fruiting branch B inflorescence C node showing stipule and petiole bases D, E flowers in bud and at anthesis F mature capsule, dehisced G seeds, lateral and dorsal (center) views. A, F, G. based on the type collection Wood & Meyer 10554; B, C, D, E based on Lorence 9476.

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).

Figure 3. Kadua lichtlei, flowering plant growing the National Tropical Botanical Garden nursery, 5 Oct. 2005, Lorence 9476 (PTBG).