Zanthoxylum dipetalum

H.Mann (1866)

This name is accepted

Kingdom: Viridiplantae Phylum: Magnoliophyta Class/Clade: Eudicot-Rosids Order: Sapindales Family: Rutaceae Genus: Zanthoxylum

kāwa‘u [kawau], kāwa‘u kua kuku kapa [kawau kua kuku kapa]

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Description

Key Characters:

Growth Form: Trees 4–15 m tall.

Stems: Trunk up to 30 cm in diameter, bark finely fissured–reticulate, new growth glabrous or finely puberulent to tomentose, young branches subtended by a pair of bud scales.

Roots:

Leaves: Leaves compound. Alternate. Leaflets 3–7, lowest pair strongly reduced or rarely 1 or both reduced leaflets absent. lowest pair of leaflets stipelliform or, if expanded, then usually folded or strongly revolute, (0.2–)1.5–3(–4) cm long, arising immediately below lowest pair of normal leaflets; normal leaflets oblong–elliptic, elliptic to broadly elliptic or sometimes broadly obovate, 6–15(–36) cm long, (2.5–)3.5–9(–13.5) cm wide, lateral petiolules articulated only at base, 3–9 mm long, terminal petiolule twice articulated, at base and near leaflet, 8–30 mm long. Leaflet apices apex obtuse to rounded. Base cuneate to rounded. Leaflet surfaces glabrous or lower surfaces rarely puberulent, conspicuously glandular punctate; blades thick, coriaceous. Margins entire rarely weakly emarginate. Normal leaflets lateral veins usually 6–8 pairs, prominent, higher order venation forming a reticulate pattern. Rachis terete (cylindrical) or winged. Stipules absent.

Flowers: Flowers usually 5–15 in terminal or leaf–opposed, open, cymose inflorescences usually 5–10 cm long, peduncles 10–40 mm long, pedicels 3–6(–8) mm long, subtended by a pair of bud scales; bracteoles 1 mm or less long. Flowers unisexual, actinomorphic. Calyx of 4 sepals, broadly ovate–deltate, 1–1.5 mm long, ciliolate. Corolla of 2 or sometimes 4 petals; petals white or yellowish white, sometimes tinged reddish, lanceolate to ovate, 6–10 mm long. Stamens 4, alternate with the petals, glabrous or pubescent, absent in pistillate flowers; anthers medifixed, dithecal. Ovary superior, 2-carpellate, but usually only 1 carpel developing, placentation axile, rudimentary in staminate flowers; ovules 2 per carpel, pendulous; style short, ± coherent; stigmas obliquely orbicular, capitate.

Fruit: Follicles 1–2; ovoid; 15–25(–33) mm long; glandular–pitted; apex conspicuously beaked; the beak 3–8 mm long; exocarp rugose; endocarp coriaceous. Seeds usually 1 per follicle; on a slender funicle; black; ovoid; 10–26 mm long.

Ploidy:

Habitat: Dry to mesic forest; sometimes along margins of wet forest.

Elevation Range: 260–1,280 m.

Historical Distribution

Images

Uses and Culture

USES

Natural History

Statewide Status

Endemic

Island Status

Kaua'i Endemic
O'ahu Endemic
Molokai Extirpated
Maui Endemic
Hawai'i Endemic

Dispersal Agents


Pollinators

Bibliography

Name Published In: Proc. Boston Soc. Nat. Hist. 10: 319 (1866)

Occurrences

SNo. Scientific Name Locality Habitat Basis of Record Recorded By Record Number Island Source Date
1 Zanthoxylum dipetalum Waimea District. Kawaiiki Ridge, slope above Koaie, west of twin falls Montane mixed dry to mesic forest, just below Metrosideros-Acacia forest with Diospyros sandwicensis, Chrysodracon cf. stenophylla (=aurea), Myrsine lanaiensis, Planchonella sandwicensis, Cryptocrya mannii, Myoporum sandwicensis, Netegis sandwicensis, Psydrax odorata, Zajnt Preserved_Specimen Wood, K.R. 16466 Kauai BISH 2015-06-04
2 Zanthoxylum dipetalum Hanalei District. Honopu Rim. Acacia koa - Metrosideros polymorpha - Dicranopteris linearis montane mesic forest w/ Alphitonia ponderosa, Melicope feddei, Antidesma platyphylla var. hillebrandii, Planchonella sandwicensis, Nestegis sandwicensis, Bobea brevipes, Melicope barbigera, Dodonaea viscosa, Ksdua affinis Preserved_Specimen Wood, K.R. 16533 Kauai BISH 2015-07-10
3 Zanthoxylum dipetalum Waimea District Koaie, headwater gulches and stream, well above Koaie river north of Mohihi-Waialae trail. Mtrosideros transitional mesic to wet forest and riparian vegetation w/ Cheirodendron , Perrottentia sadwicensis, Kadua affinis, Ilex anomala< Syzygium sadwicensis, Dodonaea viscosa, Coprosma waimeae, Cyrtandra kauaiensis, Mekicope clusiifolia, Labordia degeneri, Cyane Preserved_Specimen Wood, K.R. 15970 Kauai BISH 2014-06-24
4 Zanthoxylum dipetalum Waimea District. Kawaiiki region, north facing slopes below dividing ridge above twin falls. Metrosideros-Acacia mesic forest with Myrsine lanaiensis, Myoporum sandwicensis, Kadua affinis, Xylosma hawaiiense, Planchonella sandwicensis, Ilex anomala, Perrottetia sandwicensis, Charpentiera elliptica, Chrysodracon aurea, Elaeocar Preserved_Specimen Wood, K.R. 17175 Kauai BISH 2016-11-01
5 Zanthoxylum dipetalum Kauai Hanalei Distrcit. Kahuamaa Flat. Metrosideros-Cheirodendron-Dicranopteris montane wet forest with Kadua affinis, Dodonaea viscosa, Planchonella sandwicensis, Polyscias waimeae, P. waialealae, Melicope clustifolia, Zanthoxylum dipetalum, Ilex anomala, Bobea brevipes, Nestegis sandwicensis, Scaev___ Preserved_Specimen Wood, K.R. 18242 Kauai BISH 2019-07-11
6 Zanthoxylum dipetalum Lahaina District. W. Maui, Kauaula Valley, south slope. About one-third down from valley rim towards stream, northwest aspect. W/ Metrosideros, Sophora, Nestegis, Coprosma, Dodonaea, Pipturus, Achyranthes, Diospyros, Myrsine, Melicope, Pleomele, Remya, Dryopteris, Senna, Ipomoea, Neraudia, Lysimachia, Wikstroemia, Osteomeles, Preserved_Specimen Oppenheimer, H.L. 21405 Maui BISH 2014-02-13
7 Zanthoxylum dipetalum Manuka Ahupuaa, Manuka Natural Area Reserve, South Kona. Collected in Olopua Iki kipuka. Growing with Metrosideros polymorpha, Rockia sandwicensis, Diospyros sandwicensis, Nestegis sandwicensis, Preserved_Specimen Agorastos, N. 55 Hawaii BISH 2001-06-13