Corresponding author: Hank L. Oppenheimer (
Academic editor: L.J. Dorr
Oppenheimer HL, Bustamente KM, Perlman SP (2014) A new species of
Joseph Rock described the endemic Hawaiian genus
In addition to establishing the genus, Rock described three species:
Current status of
Extinct | Cultivation only | Extant in wild | USFWS status | IUCN status | |
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× | Species of Concern | EX | ||
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× | Species of Concern | EX | ||
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× | Endangered | CR | ||
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× | Endangered | CR | ||
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× | Endangered | CR | ||
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× | EN | |||
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× | Species of Concern | EX | ||
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× | Endangered | CR |
During the course of field work on west Maui in 2012 the authors discovered two populations (25 and 51 plants) over 400 m apart of a previously unknown
Differs from
Small trees 3–6 m tall, many branched, trunks to 30 cm dbh, bark smooth, light tan to gray, young branchlets densely white to tan pubescent with 8–12-rayed stellate trichomes 0.3–0.4 mm in diam., surface scurfy-waxy, glabrescent with age; petiole scars prominent, subcircular, 2.5–4 mm in diam. Leaves chartaceous, new growth densely stellate-pubescent, mature leaves with blades broadly-ovate to suborbicular or subreniform in outline, occasionally shallowly 3-lobed, 7.5–16(–18) cm long, (8)9.5–13.5(–18) cm wide, veins prominulous, primary veins 7–9 radiate from base, midvein with 3–4 pairs of secondary veins arising along midrib, light green to occasionally red tinged when fresh, higher order venation prominulous on both surfaces, margins irregularly broadly crenate, base cordate, with a wide to narrow but usually open sinus, apex acute to obtuse or rounded, green when fresh with scattered tan stellate pubescence on both surfaces, densely so along veins and adaxial surface, trichomes 0.2–0.4 mm in diam. with (2–)8–16 rays, abaxial surface with principal vein axils domatiate with dense tufts of tan to white trichomes 0.2–0.3 mm long; petioles 3.5–6cm long, green or sometimes red-tinged, pubescent with dense white to tan stellate trichomes as on branchlets; stipules lanceolate to subulate, 2–3.5 mm long, apex acute, green, sparsely to densely tan or white stellate pubescent, soon caducous. Flowers solitary, axillary, erect to spreading, pedicels 22–30 mm long, green or sometimes red-tinged, densely white to tan stellate pubescent as in petioles, involucral bracts 5–6 (–7), linear-subulate to lanceolate (rarely spathulate), acute to acuminate apically, connate only at base, 9–22 mm long, 1–2 mm wide at base, erect, appressed or spreading perpendicular to the floral axis in anthesis, green, densely tan or white stellate pubescent with trichomes 0.2–0.3 mm in diam. Calyx tubular-saccate, mostly 5-lobed, tube 22–30 mm long, 19–20 mm wide, the lobes triangular, acute to short acuminate 5–10 mm long, 7–8 mm wide, green, surface obscured by dense tan stellate pubescence as in bracts, in mature fruit splitting along one side but persistent. Corolla zygomorphic, adaxially curved, 5–6.5 cm long, lobed nearly to base, lobes coalescent, 6–6.5 cm long, 3.5–4 cm wide, obovate-spathulate, apex obtuse, tips and outer margins slightly reflexing with age, outer exposed portion purple, purple-green or purple-yellow, inner concealed portion yellow, conspicuously veined, densely covered with gray or tan stellate trichomes especially along veins, internally yellow or purple-tinged distally, purple toward base, corolla usually becoming purplish with age, staminal column and apex of the style exserted for 1.5–2.5 cm; staminal column 8–8.5 cm long, antheriferous in distal 3.5 cm, maroon-purple, antheriferous in distal 3.5 cm, stamens c. 100, anthers reniform-curved, 0.8–1.5 mm long, purple, filaments 6–12 mm long, purple, pollen grains purple turning golden yellow after anther dehiscence; style 8.5–9 cm long, style branches 3–5 mm long, villose, stigmas rounded, c. 1 mm long, yellow, ovary dome-shaped, 8 mm long and wide. Fruit a woody capsule, globose-cuboid to -ovoid, 5-locular, 5-valved, 2.5–3.5 (–4) cm long, 2.2–3.3 cm in diameter, surface yellowish brown, rough densely covered with dense tan stellate hair clusters, appearing tuberculate, mericarps 10, mesocarp well developed, reticulate, endocarp chartaceous, loose, with scattered long hairs, testa brown. Seeds 1–2 per mericarp, reniform, 8–10 mm long, 6–8 mm wide including the dense, lanate yellowish-tan hairs 0.4–1 mm long.
Known only from west Maui, Hawaiian Islands at
Distribution map showing known locations of
Associated tree species include:
The conservation status of
Seeds were collected from 12 individuals of
Threats to the existence of
When evaluated using the IUCN Red List criteria (
This new species clearly belongs to
1a | Involucral bracts connate ca. ½ of their length; mesocarp weakly developed and usually adnate to the exocarp; endocarp segments 5 |
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1b | Involucral bracts free or slightly connate at base; reticulate mesocarp strongly developed; endocarp segments 10 | 2 |
2a | Involucral bracts filiform or obsolete; up to 1.1 mm wide toward base | 3 |
2b | nvolucral bracts linear-subulate to spathulate, 1–7 mm wide toward base | 4 |
3a | Involucral bracts 0.5–2(–3) mm long; corolla greenish yellow externally, fading to purplish internally, 2–5(–5.5) cm long; Hualalai, Hawai`i |
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3b | Involucral bracts 18–35 mm long; corolla grayish green externally, dark magenta internally, (5–)6–7 cm long; Mauna Loa, Hawai`i |
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4a | Involucral bracts mostly 4(–5), (20–)23–27(–30) mm long |
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4b | Involucral bracts 5–7, 9–22 mm long. | 5 |
5a | Leaf lamina glabrate on both surfaces or with minute, scattered stellate trichomes only on principal veins, the trichomes sparsely tufted in principal vein axils; Kalalau Valley, Kaua`i |
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5b | Leaf lamina sparsely stellate pubescent adaxially, sparsely to densely stellate pubescent abaxially; Maui, Hawai`i | 6 |
6a | Calyx ca. 1.2 cm long; Kohala Mts., Hawai`i |
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6b | Calyx 2.2–2.5 cm long; Maui | 7 |
7a | Plants mostly sparsely pubescent; bracts linear to ligulate or spathulate, apex obtuse to rounded; capsule ovoid; Auwahi, East Maui |
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7b | Plants mostly densely pubescent; bracts linear-subulate to lanceolate, apex acute to acuminate, capsule globose-cuboid to ovoid; Kaua`ula, West Maui |
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The authors extend our deepest gratitude to Makila Land Co. and the Maui District of the Hawai`i Division of Forestry and Wildlife for permission to access the study area; the West Maui Mountains Watershed Partnership for logistical support; Windward Aviation, Inc. for their skilled helicopter pilots; Anna Palomino at the Olinda Rare Plant Facility on Maui, Ashley Trask at the National Tropical Botanical Garden (NTBG) on Kaua`i, and Nellie Sugii, Tim Kroessig, and Doug Okamoto at the Lyon Arboretum, O`ahu for the processing, propagation and storage of seeds. Bob Hobdy (DOFAW) and David Lorence (NTBG) provided useful discussions and insights, as well as reviews of earlier drafts. The staff at BISH was extremely helpful, especially Barbara Kennedy for providing high-resolution scans of many specimens in their herbarium, and we appreciate the access to type specimens; thanks also are extended to Tim Flynn (PTBG) and Warren L. Wagner (US). This manuscript was greatly improved with reviews by Lorence and Wagner, as well as an anonymous reviewer. We sincerely appreciate the beautiful illustration by Alice Tangerini (US). The Plant Extinction Prevention Program is funded in part by the U.S. Fish & Wildlife Service and the State of Hawaii Dept. of Land & Natural Resources, Division of Forestry and Wildlife.