Geniostoma imadae K. R. Wood, Lorence & W. L. Wagner sp. nov.

Figs 1, 2, 3 A, B

Diagnosis.

Geniostoma imadae is morphologically most similar to G. degeneri (Sherff) Byng & Christenh. from which it differs by its combination of leaves abaxially glabrous (vs. hirtellous), peduncle length (15 –) 20–75 mm long (vs. sessile), and capsule length 10–15 mm long with no keel (vs. 20–30 mm long with keel).

Type.

USA. Hawaiian Islands, Kaua‘i: Līhu‘e District, ‘ Iole headwaters, ♀, 22.042, -159.497, 902 m alt., 29 Jul 2021 (fr.), K. R. Wood, S. Heintzman & S. Deans 18793 (holotype: PTBG 1000098358!; isotypes (to be distributed): BISH!, CAS!, US!).

Description.

Shrubs or small trees, 1–3.5 m tall; trunk 2–5 cm diameter near base, bark gray to gray-brown; stems terete, lateral branches dichotomously branched, young and old stems glabrous. Leaves opposite, pinnately nerved, upper surface medium green, lower surface pale green; blade 3–12 (– 14) × 1.2–4.5 (– 5.5) cm, coriaceous, elliptic to elliptic-obovate, young and mature leaves glabrous on upper and lower surface, margins entire, apex apiculate to obtuse, base cuneate to acuminate, petioles (1 –) 2–15 (– 18) mm long; stipules interpetiolar, glabrous, completely connate, forming a truncate sheath 4–8 (– 11) mm long, usually splitting with age, adnate to the petiole at base. Flowers functionally unisexual, plants dioecious, inflorescence in pendulous, open paniculate cymes, flowers 3–8 in pistillate individuals, 3–10 in staminate plants, peduncles glabrous, recurved, (15 –) 20–40 mm long, elongating to 75 mm in fruit, pedicels glabrous, 10–40 mm long, elongating to 50 mm in fruit, bracts and bracteoles linear subulate, 2–5.5 × 0.1–0.8 (– 2.5) mm; calyx lobes 5 (– 6), connate near base, imbricate, linear-lanceolate or ovate-lanceolate, glabrous, apex acuminate, 5–9 × 0.8–3 mm, 5–7 nerved, margin hyaline; corolla salverform, 5 (– 6) - lobed, orange or yellow, fleshy, glabrous externally, inner tube pilose below throat, staminate and pistillate flowers 12–22 mm long, the tube 8–12 × 1–4 (– 5.5) mm, sparsely pilose within becoming densely pilose near throat, the lobes reflexed at anthesis, linear, 9–11 mm long, apex acuminate to acute; anthers 5 (– 6), adnate to corolla tube, dorsifixed, slightly exerted; staminate flowers with anthers 2.1–4 × 0.8–1.2 mm, reduced ovary glabrous 4.0 × 0.9 mm, pistil 12.5–18 mm long, stigma cylindrical and branched 5–14 mm long, style 2–4 mm long; pistillate flowers with anthers reduced, 1.2–1.8 × 0.4–0.8 mm, ovary glabrous 5.0 × 2.5 mm, pistil 12–12.5 mm long, stigma cylindrical and branched 5 mm long, style 2 mm long. Capsules green, light brown at maturity, ovoid-ellipsoid, apex acuminate, 10–15 mm long, 2 - valved, valves transversely wrinkled, not keeled, apex with beak, 2–4 mm long. Seeds ovoid-ellipsoid, brown, 1.2–1.5 × 0.7–0.8 mm, embedded in orange pulp.

Additional specimens examined (paratypes).

USA. Hawaiian Islands, Kaua‘i: Hanalei; • 1 ♀; 983 m alt.; 23 May 2022; Williams AMW 733 (PTBG) • ‘ Ili‘ili‘ula; 1 ♀; 1234 m alt.; 3 Apr 2013; Wood 15474 (BISH, PTBG) • 1 ♀; loc. cit.; 792 m alt.; 30 Jun 2021; Wood et al. 18758 (PTBG) • ‘ Iole; 1 ♀; 927 m alt.; 10 Jan 2012; Wood 14834 (PTBG) • 1 ♀; loc. cit.; 774 m alt.; 28 Aug 2013; Wood et al. 15655 (PTBG) • 1 ♀; loc. cit.; 905 m alt.; 10 Aug 2023; Wood et al. 19365 (BISH, PTBG, US) • 1 ♀; loc. cit.; 890 m alt.; 7 Aug 2024; Wood et al. 19587 (BISH, CAS, MO, NY, PTBG, US) • 1 ♀; loc. cit.; 914 m alt.; 3 Oct 2024; Wood & Heintzman 19638 (PTBG) • Kamo‘oloa; 1 ♀; 914 m alt.; 4 Oct 1996; Wood 5686 (PTBG, US) • 1 ♂, loc. cit.; 905 m alt.; 21 Feb 2008; Wood & Query 12802 (BISH, PTBG) • 1 ♂; loc. cit.; 884 m alt.; 21 Feb 2008; Wood & Query 12819 (BISH, NY, PTBG, US) • 1 ♀; loc. cit.; 923 m alt.; 27 Aug 2015; Walsh et al. SKW 90 (BISH, PTBG) • Lumaha‘i; 1 ♀; 792 m alt.; 23 Jul 2024; Wood et al. 19570 (BISH, PTBG, US) • Wahiawa; 1 ♂; 823 m alt.; 9 May 1972; Herbst & Takahashi 2401 (BISH, PTBG) • 1 ♂; loc. cit.; 716 m alt.; 3 Mar 1987; Flynn 2067 (PTBG) • 1 ♀; loc. cit.; 700 m alt.; 7 Feb 1991; Flynn et al. 4416 (PTBG) • 1 ♀; loc. cit.; 720 m alt.; 7 Feb 1991; Wood et al. 0576 (PTBG) • 1 ♂; loc. cit.; 700 m alt.; 28 Mar 1991; Wood et al. 0690 (PTBG) • 1 ♀; loc. cit.; 700 m alt.; 28 Mar 1991; Lorence et al. 6741 (BISH, F, MO, PTBG, US) • 1 ♀; loc. cit.; 790 m alt.; 10 Apr 1991; Flynn et al. 4615 (BISH, PTBG, US) • 1 ♀; loc. cit.; 13 Apr 1991; Flynn et al. 4591 (PTBG) • 1 ♀, loc. cit.; 770 m alt.; 20 Apr 1991; Flynn et al. 4611 (BISH, PTBG, US) • 1 ♀; loc. cit.; 870 m alt.; 13 May 1991; Lorence et al. 6785 (PTBG) • 1 ♀, loc. cit.; 930 m alt.; 15 May 1991; Wood et al. 0840 - A (PTBG) • 1 ♀; loc. cit.; 825 m alt.; 20 May 1991; Wood et al. 0865 (PTBG) • 1 ♂; loc. cit.; 600 m alt.; 1 Jul 1991; Wood et al. 0997 (PTBG, US) • 1 ♂; loc. cit.; 762 m alt.; 12 May 1995; Wood 4272 (PTBG) • 1 ♀; loc. cit.; 762 m alt.; 12 May 1995; Wood 4273 (NY, PTBG) • 1 ♀; loc. cit.; 732 m alt.; 15 Jan 2002; Perlman & Hill 17891 (BISH, NY, PTBG, US) • 1 ♂; loc. cit.; 975 m alt.; 28 Feb 2002; Perlman & Hill 17920 (BISH, MO, NY, PTBG) • 1 ♀; loc. cit.; 914 m alt.; 28 Feb 2002; Perlman & Hill 17929 (PTBG, US) • 1 ♂; loc. cit.; 899 m alt.; 4 Apr 2003; Perlman 18532 (MO, PTBG, US) • 1 ♀; loc. cit.; 797 m alt.; 6 Apr 2009; Tangalin et al. 2003 (MBK, PTBG, US) • 1 ♀; loc. cit.; 783 m alt.; 28 Jun 2012; Perlman & Kishida 22954 (BISH, NY, PTBG, US) • 1 ♀; loc. cit.; 725 m alt.; 2 Nov 2012; Perlman 23089 (PTBG) • 1 ♀; loc. cit.; 759 m alt.; 23 May 2013; Perlman & Kishida 23474 (PTBG) • Waiahi; 1 ♀; 914 m alt.; 25 Nov 2013; Wood et al. 15743 (BISH, PTBG, US) • 1 ♀; loc. cit.; 792 m alt.; 30 Dec 2013; Wood et al. 15770 (BISH, PTBG, US) • 1 ♂; loc. cit.; 790 m alt.; 4 Apr 2019; Wood et al. 18141 (BISH, NY, PTBG, US) • 1 ♂; loc. cit.; 805 m alt.; 4 Apr 2019; Wood et al. 18144 (PTBG, US) • 1 ♀; loc. cit.; 815 m alt.; 4 Apr 2019; Wood et al. 18154 (PTBG, US) • Wainiha; 1 ♀; 732 m alt.; 23 Apr 2014; Wood et al. 15930 (BISH, CAS, PTBG, US).

Phenology.

Geniostoma imadae has been observed with flower during the months of January to August, and with fruit October to February and April to August.

Etymology.

Geniostoma is derived from the Greek geneion, beard, and stoma, mouth, referring to the hairs on the inner rim of the corolla (Smith and Stone 1962; Lorence and Wagner 2020). The epithet of this new species recognizes Clyde Imada, Research Specialist at the Bishop Museum. It is with great respect and admiration for his many contributions to Hawaiian botany that we name this species in his honor.

Vernacular name.

Kāmakahala is the Hawaiian name for related species. The highly prized flowers of the Hawaiian members of the genus were used for leis and wreaths and reserved only for high chiefs (Hillebrand 1888).

Affinities.

Molecular phylogenetic analyses based on target-enrichment nuclear data using the Angiosperms 353 probe set (Johnson et al. 2019; Lichter-Marck et al. unpubl. data) support the recognition of two distinct lineages in the Hawaiian Islands, corresponding to Geniostoma subg. Labordia sect. Labordia and G. sect. Darbolia recognized by Conn (1980). The new taxon belongs to sect. Labordia, which is characterized by corollas orange-yellow and usually salverform in shape (vs. sect. Darbolia with corollas white to greenish and urceolate) (Table 1).

Morphologically, Geniostoma imadae is most similar to G. degeneri (Fig. 4 A – C), yet can be easily separated by features stated in the diagnosis. The leaves, stipules and flowers of G. imadae are also quite similar to G. pumilum (Hillebr.) Byng & Christenh. (Fig. 4 D – F), yet G. imadae starkly differs in having stems terete (vs. sharply angled or winged), peduncles 20–75 mm long (vs. 0–6 mm), corolla lobes 9–11 mm long (vs. 5–7 mm), corolla glabrous externally (vs. hirsute), and capsules not keeled, 2 - valved (vs. keeled, 3 - valved). Interestingly, G. imadae has been misidentified as G. tinifolium (A. Gray) B. J. Conn because of their superficial similarity in having long pedunculate cymes, yet both belong to different lineages with G. imadae being a member of sect. Labordia (vs. sect. Darbolia for G. tinifolium). Peduncle length has been used to distinguish these sections previously, but is not congruent with floral traits and molecular phylogenetic evidence. Taxa with elongate peduncles are compared in Table 2. Geniostoma imadae clearly differs from G. tinifolium in having corolla tubes 8–12 mm long (vs. 5.5–8 mm), corolla lobes 9–11 mm long (vs. 1.5–3 mm), corolla color orange-yellow (vs. green-yellow), corolla shape salverform (vs. urceolate) stipules glabrous (vs. ± ciliate), and capsules not keeled, 2 - valved (vs. keeled, 2 (3) - valved). (Tables 1, 2).

Distribution and ecology.

Geniostoma imadae is endemic to the volcanic island of Kaua‘i, where it is has been documented along the central northern ridges, slopes and riparian valleys of Wainiha, Lumaha‘i and Hanalei and extends south along the islands central eastern windward regions of ‘ Ili‘ili‘ula, ‘ Iole, Kamo‘oloa, Waiahi, and Wahiawa (Figs 3 C, 5). We estimate ca. 800 to 1250 individuals occur in lowland to montane wet forests ranging in elevation between 600–1234 m and dominated by trees of Metrosideros Banks ex Gaertn. (Myrtaceae) and Cheirodendron Nutt. ex Seem. (Araliaceae). Greater numbers of G. imadae are found along forested stream banks but also inhabit upper forested slopes that extend up to dividing ridges and border expansive patches of matting ferns such as Dicranopteris Bernh. and Diplopterygium (Diels) Nakai (Gleicheniaceae). Associated genera of trees and shrubs include Polyscias J. R. Forst. & G. Forst. (Araliaceae); Pritchardia Seem. & H. Wendl. (Arecaceae); Dubautia Gaudich. (Asteraceae); Cyanea Gaudich. (Campanulaceae), Perrottetia Kunth (Dipentodontaceae); Antidesma L., Euphorbia L. (Euphorbiaceae); Hydrangea Gronov. (Hydrangeaceae); Geniostoma (Loganiaceae); Myrsine L. (Primulaceae); Syzygium Gaertn. (Myrtaceae); Bobea Gaudich., Coprosma J. R. Forst. & G. Forst., Kadua Cham. & Schltdl., Psychotria L. (Rubiaceae); Melicope J. R. Forst. & G. Forst. (Rutaceae); and Pipturus Wedd., Touchardia Gaudich. (Urticaceae). Genera of sedges and grasses include Carex L., Cyperus L., Machaerina Vahl (Cyperaceae); Eragrostis Wolf, Panicum L. (Poaceae); herbs and sub-shrubs include Bidens L. (Asteraceae); Vaccinium L. (Ericaceae); Cyrtandra J. R. Forst. & G. Forst. (Gesneriaceae); and Freycinetia Gaudich. (Pandanaceae). Genera of ferns include Asplenium L., Hymenasplenium Hayata (Aspleniaceae); Deparia Hook. & Grev., Diplazium Sw. (Athyriaceae); Sadleria Kaulf. (Blechnaceae); Cibotium Kaulf. (Cibotiaceae); Microlepia C. Presl (Dennstaedtiaceae); Ctenitis (C. Chr.) C. Chr., Dryopteris Adans. (Dryopteridaceae); Hoiokula S. E. Fawc. & A. R. Sm., and Menisciopsis (Holttum) S. E. Fawc. & A. R. Sm. (Thelypteridaceae). There is also a diverse association of terrestrial and epiphytic lichens and bryophytes. The holotype of Geniostoma imadae was collected in the immediate area of the recently discovered and described species Melicope iolensis K. R. Wood, Lorence & W. L. Wagner (i. e., ‘ Iole Valley, Wood et al. 2024), attesting to the floristic diversity of the region and the importance of ongoing botanical inventories and conservation.