Clermontia hanaulaensis H.Oppenheimer, Lorence, & W.L.Wagner, 2023

Oppenheimer, Hank, Lorence, David H. & Wagner, Warren L., 2023, Clermontia hanaulaensis (Campanulaceae, Lobelioideae), a new, critically endangered species from Maui, Hawaiian Islands, PhytoKeys 227, pp. 167-179 : 167

Clermontia hanaulaensis H.Oppenheimer, Lorence, & W.L.Wagner sp. nov.

Type.

USA. Hawaiian Islands: Maui: west Maui, Wailuku District, slopes of Hana‘ula, Pōhākea Gulch , ca. 1183 m, 4 Aug 2021, H. Oppenheimer & K. Severson H82102 (Holotype: PTBG [PTBG1000093350]; Isotypes BISH, US). Figs 2 , 3 .

Description.

Shrubs or small trees up to 3 m tall, flowering at 1.5-3 m tall, terrestrial, branched from near base, with repeated candelabra-like branching, bark rugose-fissured, light brown, leafy branches green, latex white. Leaves clustered at the distal ends of the branches, alternate, with short internodes, simple, petiolate; lamina 10-12(-18) cm long, 2.0-3.5(-4) cm wide, narrowly elliptic to oblanceolate, chartaceous; adaxial surface green, glossy when fresh, drying dull, glabrous; abaxial surface paler than adaxial surface, glabrous, secondary veins 15-16 on each side; margins entire in basal ¼, otherwise callose-crenulate; apex acute to short-acuminate, occasionally with a short mucro 1 mm long; base cuneate to attenuate; petiole 3-4(-6) cm long, glabrous; seedling leaves pubescent. Inflorescence (2)3-4(-5)-flowered, glabrous; flowers 5-merous; peduncle 15-30(-42) mm long; bracts triangular, ca. 1 mm long, deciduous; pedicels 8-18 mm long; bracteoles basal, 1.0-1.2 mm long, narrowly lanceolate, acute to acuminate, sometimes short mucronate, ciliate; hypanthium obconic or hemispheric, green, ca. 7-10 mm long, 8-10 mm wide; corolla weakly zygomorphic to nearly rotate when fresh, slightly to moderately curved, perianth (30-)35-45(-50) mm long, perianth tube 15-25(-27) mm long, 9-10 mm wide, the lobes 20-26 mm long, (2.0-)3.0-3.5 mm wide, the dorsal and ventral lobes spreading in distal half, pale violet-purple, often suffused with creamy white streaks, occasionally creamy white, glabrous; calyx 1/2-4/5 as long as petals, lobes petaloid, similar in color to corolla, often pale greenish tinged toward base, sometimes creamy white with violet-purple irregular veins, lobes connate for 1/3-1/2 their length, not appressed to petals, erect to spreading; staminal column violet, 2.0-2.5 mm wide, filaments 30-40 mm long, anthers darker violet, anther tube 9-12 mm long, 2.3-3.0 mm wide. Fruit dull orange, obconic to turbinate, 15-20 mm long, 10-15 mm wide, smooth, sepals and petals caducous. Seeds obovoid, slightly compressed, 0.5-0.6 mm long, 0.5 mm wide, testa dark brown, glossy, smooth.

Distribution.

Clermontia hanaulaensis is known only from a single population on west Maui in several small ridges and gullies on the slopes below Hana‘ula, in the Pōhākea Gulch.

Habitat and ecology.

Clermontia hanaulaensis occurs in Metrosideros Banks ex Gaertn. Montane Wet Forest ( Wagner et al. 1999) at ca. 1158-1213 m elevation with an annual rainfall of ca. 2600-2900 mm. The common associated woody elements are species of Cheirodendron Nutt. ex Seem., Clermontia Gaud., Coprosma J.R. Forst. & G. Forst., Cyrtandra J.R. Forst. & G. Forst., Hydrangea L., Ilex L., Kadua Cham. & Schltdl., Myrsine L., Perrottetia Kunth, Pipturus Wedd., and Psychotria L. Pteridophyte genera include Athyrium Roth, Cibotium Kaulf., Dicranopteris Bernh., Diplazium Sw., Dryopteris Adans., and Sadleria Kaulf. that are prevalent and form a dense ground cover. Freycinetia arborea Gaudich. is a widespread liana. Common epiphytes include species of Adenophorus Gaudich., Asplenium L., Elaphoglossum Schott ex J. Sm., and several herbaceous species of Peperomia Ruiz & Pav. The terrestrial sedge Carex alligata Boott is occasional. The herbaceous Ranunculus mauiensis A. Gray is a distinctive, but extremely rare element of this plant community.

Soil is of typical basaltic origin derived from the original shield-building Wailuku Volcanic Series ( Stearns and MacDonald 1942). The average annual rainfall is approximately 2700 mm. ( Giambelluca et al. 1986).

Clermontia arborescens subsp. arborescens occurs sympatrically throughout the range of C. hanaulaensis , whereas C. grandiflora subsp. munroi is scattered although locally common, and C. grandiflora subsp. grandiflora occurs at the upper perimeter of the population. Even further away in much wetter habitat with annual rainfall above ca. 2900 mm are populations of C. micrantha (Hillebrand) Rock, while C. kakeana occurs in lower, drier areas with annual rainfall below ca. 2600 mm. These taxa are readily distinguished morphologically from C. hanaulaensis by the characters given in the key to the Maui species below.

Phenology.

Clermontia hanaulaensis has been observed to be flowering from July through September, with fruit maturing from August through October.

Etymology.

The specific name honors Hana‘ula, a peak on southern Mauna Kahālāwai (aka west Maui Mountains). Lit. red bay ( Pukui et al. 1966); + Latin suffix - ensis, indicating a place of origin or growth. The Hawaiian vernacular names ' ōhā wai, ' ōhā, hāhā, ' ōhāhā, ' ōhā wai nui, and ' ōhāhā wai nui apply to other species of Clermontia ( Pukui and Elbert 1986; Lammers 1991; Wagner et al. 1999).

Specimens examined

(paratypes). USA, Hawaiian Islands. Maui, Wailuku District, slopes of Hana‘ula, Pōhākea Gulch , 30 Jul. 2020, H. Oppenheimer H72005 (BISH, PTBG, US); H. Oppenheimer H72006 (BISH, PTBG); H. Oppenheimer H72007 (BISH, PTBG, US); H. Oppenheimer H72008 (BISH); H. Oppenheimer H72009 (BISH); 21 Aug. 2020, H. Oppenheimer & K. Bustamente H82005 (BISH, PTBG); H. Oppenheimer & K. Bustamente H82006 (BISH); 28 Sep. 2020, H. Oppenheimer & K. Severson H92014 (BISH, PTBG, flowers and mature fruit in alcohol); H. Oppenheimer & K. Severson H92015 (PTBG); 2 Oct. 2020, H. Oppenheimer H102002 (BISH), H. Oppenheimer H102003 (BISH); 10 Sep. 2021, H. Oppenheimer & Z. Pezzillo H92101 (BISH, PTBG, US) .

Figures

Figure 2. Clermontia hanaulaensis H. Oppenheimer, Lorence & W. L. Wagner A habit of flowering stem B detail of flower at anthesis C fruit. (A, B, drawn from type collection and field images of type plant (Oppenheimer & Severson H 82102; isotype US) C drawn from field image of non-type plant in Pōhakea Gulch). Illustration by Alice Tangerini.

Figure 3. Clermontia from Pōhakea Gulch area, west Maui A-C Clermontia hanaulaensis H. Oppenheimer, Lorence & W. L. Wagner A, B habit, from field images of type collection with purple and white perianth (from Oppenheimer & Severson H 82102) C mature fruit, taken in Sep. 2020 D-F from other Clermontia plants in Pōhakea Gulch showing variations that could represent hybridization between C. hanaulaensis and other sympatric species or between other species in the area D habit, form with shorter, wider calyx showing slight separation of calyx tube from corolla tube, taken in Sep. 2020 (unvouchered) E habit, form with shorter, wider calyx, taken in Aug. 2020 (unvouchered) F habit, form with white perianth, taken in Aug. 2020 (H. Oppenheimer & K. Severson H 82101, BISH, PTBG, US). All photos by H. Oppenheimer.