Cyrtandra gregoryi 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 : 87-89

Cyrtandra gregoryi M.A.Johnson sp. nov. Figs 1 , 2

Diagnosis.

Cyrtandra gregoryi is closely related to C. ciliata Seem. (Fig. 2 ), but differs in its elliptic to ovate leaves up to 39 × 17 cm (vs. lanceolate to ovate leaves up to 28 × 12 cm), axillary inflorescences with indument of brown trichomes (vs. cauliflorous inflorescences with indument of white trichomes), pale green calyces 6-13 mm long that are cleft unequally into lanceolate coriaceous lobes (vs. calyces white, 7-10 mm long, cleft nearly to the base into equal linear-lanceolate lobes), these splitting along two to three sutures and recurving after anthesis (vs. remaining erect after anthesis), and corollas with exserted style and stamens (vs. style and stamens included).

Type.

FIJI. Taveuni : near the end of the Lavena coastal walk along the Wainibau stream, ca. 3.5 km NW of Lavena Village, 16°52.10'S, 179°54.32'W, 32 m elev., 04 August 2014, M.A. Johnson 105 with G.J. Hora (holotype: RSA).

Description.

Shrub 0.9-2.2 m tall; stems unbranched to few-branched, with a dense indument of dark brown uniseriate multicellular trichomes ca. 0.5 mm long. Leaves opposite, internodes 2-7 cm long, blades elliptic to ovate to obovate, 22-39 cm long, 7-17 cm wide, upper surface sparsely strigillose, lower surface glabrate except for the densely pubescent 9-13 secondary veins on each side, margins serrulate to subentire, apex acute, base cuneate to rounded, petioles 5-11 cm long, densely pubescent with short brown trichomes; inflorescence an axillary cyme with dense brown pubescence on the peduncles and pedicels, 3-22 flowers, cymules 1-4 flowered, peduncle to 31 mm long, terminated by bracts to 6 mm long, narrowly lanceolate, deciduous after anthesis, pedicels to 31 mm long; calyx 6-13 mm long, outer surface pale green and moderately pubescent with appressed dark brown uniseriate trichomes, inner surface white and papillate, unequally cleft into 5 lanceolate coriaceous lobes, 3-10 mm long, apex acuminate, upper lobes occasionally connate, often continuing to split along two or three sutures and curl back after anthesis, deciduous; corolla white, tube funnelform, slightly curved near mid point, 23-27 mm long, 6-9 mm wide, outer surface glabrate to densely pubescent with short glandular trichomes, inner surface glabrous, upper lobes 5-7 mm long and 5-6 mm wide, lower lobe 7-8 mm long and 5-6 mm wide, lobes recurving after anthesis; stamens 2, ca. 9 mm long, becoming exserted from the corolla tube during ovulate phase, base of the filaments bright orange, anthers apically connate, staminodes 3; nectary disc cupulate, annular; gynoecium (ovary, style, and stigma) 16-24 mm long, ovary glabrous, style pubescent with capitate glandular trichomes, exserted, stigma shallowly bilobed; fruit not seen.

Distribution and ecology.

Cyrtandra gregoryi is only known from two locations in eastern Taveuni, Fiji, where it grows in lowland forests and along stream banks from ca. 30-50 m (Fig. 3 ).

Phenology.

Individuals of this species were in flower when collected in August and November, with fruits likely becoming mature ca. 5-6 months later.

Etymology.

I am pleased to name this new species after my husband, Gregory Hora, to whom I am most grateful for his assistance in collecting this and other species across Fiji.

Phylogenetic placement.

A recent phylogenetic study by Johnson et al. (2017) placed Cyrtandra gregoryi sister to C. ciliata with strong support (Fig. 4 ). Cyrtandra ciliata is endemic to the Fijian islands of Vanua Levu, Taveuni, and Koro from 300-1100 m elevation. These species share a cymose inflorescence and glabrous to glabrate leaves. The key provided in the taxonomic treatment by Gillett (1967) would place C. gregoryi in species Group 5 based on the branching cyme inflorescence, non-woody inflorescence axis, deciduous calyx, styles and/or stamens being exserted from the corolla tube, and stamens 8-12 mm long.

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), inferred decline in area of occupancy (B2bii), decline in area, extent, and/or quality of habitat (B2biii), decline in number of mature individuals (B2bv), and population size estimated to number fewer than 250 mature individuals (D).

Although Bouma National Heritage Park protects ca. 15,000 hectares of intact rainforest on eastern Taveuni, indigenous Fijians are permitted to clear land near villages for agriculture. As a result, large areas of coastal forest are increasingly being cleared for dalo (taro, Colocasia esculenta (L.) Schott) and yaqona (kava, Piper methysticum L.f.), the two main export crops of Taveuni. Given that C. gregoryi appears to be restricted to low-elevation forests, it is highly likely that individuals of this species were extirpated during clearing for human settlements and agriculture. Invasive plants are also a major threat to native plants in the area; mile-a-minute vine (kudzu, Pueraria lobata (Willd.) Ohwi) may be particularly problematic as it rapidly grows over trees and shrubs and can kill other plants with heavy shading. Lastly, anthropogenic-induced climate change is a threat to island plant communities. Tropical cyclones are expected to increase in intensity and severity in the coming years (Emmanuel 2005, Knutson 2010), and can have devastating effects on island vegetation due to high winds, flooding, and storm surges (e.g., Cyclone Pam in 2015 caused extensive damage to Vanuatu’s forests). Most recently, Cyclone Winston, the strongest tropical cyclone to make landfall in the South Pacific Basin in recorded history, ravaged the islands of Fiji in February of 2016. The coastal regions of eastern Taveuni were inundated by massive storm surges, and much of the vegetation was damaged by winds of up to 185 mph. Although forested regions can often regenerate after a natural disaster if given sufficient time, recent research in the South Pacific suggests that a cyclone can be a catalyst for human-coping strategies that increase pressure on forest ecosystems and exposes them to invasive plant species ( Goulding et al. 2016).

Additional specimens examined.

FIJI. Taveuni : Tavoro Falls Trail in Bouma National Heritage Park, 19 November 2016, J.C. Game 16/235 with S. Fawcett (PTBG) .

Notes.

Eight individuals of C. gregoryi were recorded during field surveys along the Lavena coastal trail, with all of these being reproductive. Additional field surveys in the area are likely to reveal more individuals. No other Cyrtandra species were observed growing sympatrically with C. gregoryi in the Lavena region, although C. tempestii Horne ex. C.B. Clarke was collected 0.64 km to the SE. An additional collection was made of a single individual of C. gregoryi near the Tavoro Falls in Bouma National Heritage Park, an area that also hosts C. ciliata .

Figures

Figure 1. Cyrtandra gregoryi M. A. Johnson A Habit B Inflorescence C Corolla, anterior view D Calyx E Flower, lateral view F Gynoecium. Drawn from Johnson 105 (RSA) and field images.

Figure 2. Cyrtandra gregoryi M. A. Johnson and closest relative (C. ciliata) based on a molecular phylogeny by Johnson et al. (2017). A C. gregoryi shrub habit B C. gregoryi corolla, anterior view C C. gregoryi flower, lateral view D C. gregoryi axillary cyme inflorescence E C. gregoryi adaxial leaf surface F C. ciliata corolla, anterior view G C. ciliata flower, lateral view H C. ciliata cauliflorous cyme inflorescence. All photos taken in the field by M. Johnson.

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.