Neoarytera Callm., Buerki, Munzinger & Lowry, 2020

Buerki, Sven, Munzinger, Jérôme, Lowry Ii, Porter P. & Callmander, Martin W., 2020, Two new genera of Sapindaceae (Cupanieae) from the southern Pacific: Lepidocupania and Neoarytera, Candollea 75 (2), pp. 269-284 : 280

Neoarytera Callm., Buerki, Munzinger & Lowry , gen. nov.

( Fig. 3D–F ).

Type: Neoarytera chartacea (Radlk.) Callm., Buerki, Munzinger & Lowry (≡ Arytera chartacea Radlk. ). = Arytera subsect. Pacifica H. Turner in Blumea, Suppl. 9: 151. 1995.

Type: Arytera collina Pancher & Sebert (≡ Neoarytera collina (Pancher & Sebert) Callm., Buerki, Munzinger & Lowry ).

Trees. Indument comprising short, straight, appressed trichomes; glandular scales absent; buds not “varnished”. Leaves alternate, 1–4-jugate; leaflets opposite to subopposite, subsessile to petiolulate, margin entire. Inflorescences axillary or pseudo-terminal. Flowers actinomorphic, functionally unisexual; calyx 5-dentate, teeth equal; petals 5, with a distinct claw, scales minute, petal margin with minute enations; disc more or less distinctly five-lobed, rim subpilose; stamens (6–)8(– 10), anthers basifixed; ovary (2 –)3-locular. Fruit a capsule, with 1 or 2 well developed lobes, dehiscence loculicidal, central axis distinctly thickened, glabrous to puberulous and rugose to verrucose outside, pilose inside, calyx persistent; seed ellipsoid, sarcotesta covering all or sometimes only half of the seed ( N. neoebudensis ), fleshy-membranaceous, comprising a single layer. Radicle bearing trichomes, at least basally.

Distribution. – Neoarytera comprises four species, three endemic to New Caledonia and one occurring on both New Caledonia and Vanuatu ( Fig. 4 ).

Notes. – Neoarytera is characterized by the distinctly thickened central axis of its fruit (vs. not thickened in Arytera and Cupaniopsis ), petal scales comprising minute enations (vs. scales adnate to the margins of the petals or free from the petals in the other two genera), and its 3-, rarely 2-locular ovary and fruit (vs. ovary and fruit 2- or 3-locular in the two other genera). Arytera , as re-circumscribed here, can easily be distinguished by its 2-layered sarcotesta (vs. single-layer in Cupaniopsis and Neoarytera ) ( TURNER, 1995: 72). Finally, Cupaniopsis differs from Arytera and Neoarytera by having free or nearly free calyx lobes, which are usually 2-seriate, orbicular, elliptic or obovate, and concave (vs. calyx shortly cupular, the lobes toothed or divided, and usually ovate in the other two genera) ( REYNOLDS, 1985a).

Figures

Fig. 3. – A. Lepidocupania glomeriflora (Radlk.) Buerki, Callm., Munzinger & Lowry (New Caledonia); B. Lepidocupania brackenridgei (A. Gray) Buerki, Callm., Munzinger & Lowry (Vanua Levu, Fiji); C. Lepidocupania lepidota (Radlk.) Buerki, Callm., Munzinger & Lowry (New Caledonia); D. Neoarytera collina (Pancher & Sebert) Callm., Buerki, Munzinger & Lowry (New Caledonia); E. Neoarytera neoebudensis (Guillaumin) Callm., Buerki, Munzinger & Lowry (New Caledonia); F. Neoarytera chartacea (Radlk.) Callm., Buerki, Munzinger & Lowry (New Caledonia). [A: Callmander et 788; B: Munzinger 379; C: Munzinger 7700; D: Munzinger 7395; E: Munzinger 7404; F: Hequet 3525] [Photos: A–B, D– E: P. Lowry; C: J. Munzinger; F: V. Hequet]

Fig. 4. – Distribution map of Lepidocupania Buerki, Callm., Munzinger & Lowry (black line) and Neoarytera Callm., Buerki, Munzinger & Lowry (white line) in the southern Pacific. [Oceania Region Map by Vemaps.com]