Cyrtandra hispida M.A.Johnson, 2017

Johnson, Melissa A., 2017, Four new species of Cyrtandra (Gesneriaceae) from the South Pacific islands of Fiji, PhytoKeys 91, pp. 85-104 : 89-92

Cyrtandra hispida M.A.Johnson sp. nov. Figs 5 , 6

Diagnosis.

Cyrtandra hispida is morphologically similar to C. waisaliensis sp. nov., but differs in its axillary cyme inflorescence of 2-4 flowers (vs. cauliflorous cyme inflorescence of 2-8 flowers), green bracts and bracteoles 5-9 mm long (vs. white bracts and bracteoles 3-10 mm long), calyx pale green and 29-31 mm long (vs. calyx white and 23-37 mm long), corolla tube 31-34 mm long (vs. corolla tube 23-27 mm long), and staminodes 2 (vs. staminodes 3).

Type.

FIJI. Taveuni : Des Voeux Peak, 16°50.48'S, 179°57.97'W, 1109 m elev., 13 July 2014, M.A. Johnson 91 with G.J. Hora (holotype: RSA; isotype: SUVA).

Description.

Shrub 0.6-1.2 m tall; stems unbranched or few-branched, with light brown hispid uniseriate multicellular trichomes ca. 5 mm long. Leaves opposite, internodes 3-9 cm long, the blades oval to ovate to obovate, 15-22 cm long, 8-10 cm wide, upper and lower surfaces densely strigose with light brown uniseriate trichomes to 2 mm long, 5-7 secondary veins on each side, margins serrate to biserrate, apex acute to acuminate, base oblique or aequilateral and rounded to cuneate, petioles 4-9 cm long, densely pubescent with hispid trichomes ca. 6 mm long; inflorescence an axillary cyme, 2-4 flowered, densely hispid throughout, peduncle 10-14 mm long, terminated by green bracts 5-9 mm long, ovate to narrowly lanceolate, densely hispid, pedicels 27-28 mm long, often subtended by bracteoles similar to the outer bracts; calyx pale green, cylindrical, 29-31 mm long, unequally cleft into five triangular lobes 4-11 mm long, outer and inner surfaces densely hispid with uniseriate trichomes, persistent on developing fruits; corolla white, bilabiate, tube narrowly funnelform, slightly curved near mid point, outer and inner surface glabrous, 31-34 mm long and 8-9 mm wide, upper lobes 12-15 mm long and 10-14 mm wide, lower lobe 13-20 mm long and 10-15 mm wide; stamens 2, ca. 7 mm long, anthers apically connate, staminodes 2; nectary disc cupulate, annular, deciduous from the fruit; gynoecium (ovary, style, and stigma) ca. 22 mm long, ovary and style glabrous, stigma applanate, bilobed; berries green when immature, ellipsoid, glabrous, up to 18 mm long and 11 mm wide, tipped by the basal 3 mm of the persistent style, enclosed by the persistent calyx, mature fruit not seen.

Distribution and ecology.

Cyrtandra hispida is only known from two populations in the upland rainforests of Taveuni, Fiji, where plants occur on exposed hillsides composed of volcanic cinders, and on rocky stream banks from 697-1126 m elevation (Fig. 3 ).

Phenology.

Individuals of this species were in flower when collected in July, with fruits likely becoming mature ca. 5-6 months later (December-January).

Etymology.

This species is named for the stiff trichomes that cover the stems, leaves, and inflorescences.

Phylogenetic placement.

A recent phylogenetic study by Johnson et al. (2017) placed Cyrtandra hispida in a weakly supported clade with four other species ( C. cephalophora Gillespie, C. waisaliensis sp. nov., C. dolichocarpa A. Gray, C. longifructosa sp. nov.) that are recorded from the Fijian Islands of Viti Levu ( C. cephalophora ) and/or Vanua Levu ( C. cephalophora , C. waisaliensis , C. dolichocarpa , C. longifructosa ) (Fig. 4 ). Within this clade, C. hispida is most similar morphologically to C. waisaliensis (sp. nov., described below). Both species have large bilabiate corollas, persistent cylindrical calyces, ovate to obovate leaves, and a dense indument of long stiff trichomes covering the stems, leaves, and inflorescences. Additional sampling of species and of nuclear genic regions may be required to confidently place C. hispida with its closest relatives. The key provided in the taxonomic treatment by Gillett (1967) would place C. hispida in species Group 2 based on the branching cyme inflorescence and the persistent calyx.

Conservation status.

Proposed IUCN Red List Category: Endangered (EN) based on an estimated area of occupancy of <500 km2 (criterion B2), known to exist at no more than five locations (B2a), projected decline in extent of occurrence (B2bi), area of occupancy (B2bii), and area, extent, and/or quality of habitat (B2biii). Although the two areas where this species has been collected are within the Taveuni Forest Reserve, the forest above Somosomo Village is currently being cleared for a hydropower dam (M. Johnson, pers. obs.). Additional threats include mining for gold and copper, invasion by plant species such as Clidemia hirta (L.) D. Don ( Koster’s curse; M. Johnson, pers. obs), and damage from tropical cyclones. Further surveys are needed in the upland forests of Taveuni (which remain relatively unexplored, exceptions being the area surrounding Lake Tagimoucia and the road to Des Voeux Peak) to determine the extent of occurrence and population demographics of C. hispida .

Additional specimens examined.

FIJI. Taveuni : mountains above Somosomo, 16°47.67'S, 179°56.10'W, 693 m elev., 24 August 2015, M.A. Johnson 212 (SUVA), M.A. Johnson 215 ( RSA).

Notes.

Cyrtandra hispida was observed to grow sympatrically with three species on Des Voeux Peak ( C. leucantha A.C. Sm., C. ciliata , and Cyrtandra sp.) and three species in the mountains above Somosomo ( C. leucantha , C. ciliata , C. taviunensis Gillespie). Several individuals were observed that appeared to be of hybrid origin in these populations, with the widespread and common C. ciliata inferred as one of the parents based on similar floral morphology. While the observation of ongoing hybridization in these populations suggests the possibility of C. hispida being of hybrid origin, none of the sympatric species have morphological characters similar to C. hispida . Furthermore, C. hispida is placed in a clade of species that are endemic to the neighboring islands of Vanua Levu and Viti Levu, and does not appear to be closely related to species endemic to Taveuni.

Figures

Figure 3. Distribution of Cyrtandra gregoryi and C. hispida on Taveuni, Fiji.

Figure 4. A portion of the Maximum Likelihood phylogram from Johnson et al. (2017) based on three nuclear (ITS, ETS, Cyrt 1) and two chloroplast (psb A- trn H, rpl 32 - trn L) loci. Support values shown for each branch are bootstrap and posterior probabilities when ≥ 50 % and ≥ 0.50, respectively. An asterisk indicates 100 % BS or 1.0 PP; a dash indicates that the branch was not supported.

Figure 5. Cyrtandra hispida M. A. Johnson. A Habit B Inflorescence C Corolla, anterior view D Corolla, longitudinal section E Calyx, longitudinal section and young fruit. Drawn from Johnson 91 (RSA, SUVA), Johnson 212 (SUVA), Johnson 215 (RSA), and field images.

Figure 6. Cyrtandra hispida M. A. Johnson and closest relative (C. cephalophora) based on molecular phylogeny by Johnson et al. (2017). A C. hispida corolla, anterior view B C. hispida flower, lateral view C C. hispida shrub habit and axillary cyme inflorescence D C. cephalophora shrub habit E C. cephalophora capitate-cylindrical cauliflorous inflorescence and young fruits F C. cephalophora corolla, anterior view. All photos taken in the field by M. Johnson, with photos of C. hispida taken from the type collection.