Picrella, Baill.

Hartley, Thomas G. & Mabberley, David J., 2003, The identity of Picrella Baill. (Rutaceae) with a revision of the genus, Adansonia (3) 25 (2), pp. 251-259 : 252-253

PICRELLA Baill.

Adansonia 10: 150 (1871) & Hist. Pl. 4: 410, 497

(1873) & Dict. Bot. 3: 593 + tt. (1891); Engler, Nat.

Pflanzenfam. III, 4: 222 (1896) & ed. 2, 19a: 389

(1931). — Type: P. trifoliata Baill.

Zieridium Baill., Adansonia 10: 303 (1872) & Hist. Pl. 4: 462 (1873); Engler, Nat. Pflanzenfam. III, 4: 138 (1896) & ed. 2, 19a: 256 (1931); Guillaumin, Bull. Soc. Bot. France 85: 299 (1938). — Type: Z. gracile Baill. (= P. trifoliata Baill. var. gracilis (Baill.) T.G. Hartley & Mabb. ); syn. nov. It is curious, and raises some obvious questions, that BAILLON did not mention Zieridium in his Dictionnaire de Botanique. His only references to the genus, which predate the Dictionnaire, appear to be those in Adansonia and Histoire des Plantes cited herein.

Shrubs or small trees with conspicuous to inconspicuous punctate oil glands, particularly in the leaves and pericarp; trichomes simple. Leaves opposite, trifoliolate, unifoliolate, or simple; blades pinnately veined. Inflorescences axillary or occasionally axillary and infrafoliar, cymulose to thyrsiform or reduced to compound or simple racemes or solitary flowers. Flowers functionally unisexual or rarely bisexual; sepals 4, connate at base, rounded to ovate, persistent in fruit; petals 4, distinct, valvate in bud, ovate-elliptic, hooked adaxially at apex, often becoming recurved, persistent or deciduous in fruit; stamens 4 or 8 (antisepalous ones rudimentary in ♀ flowers; antipetalous ones consistently rudimentary), distinct or the antipetalous ones basally adherent to petals, filaments lanceolate to sublinear, anthers ellipsoid or broadly so (without pollen and usually flattened or obsolete in rudimentary stamens), dorsifixed, introrse; disc intrastaminal, glabrous or nearly so, pulvinate to annular, 4- or 8-lobed or undulate; gynoecium (rudimentary in Ƌ flowers) 4-loculed and -carpelled, carpels joined laterally in the style, otherwise like the fruiting carpels distinct or very shortly connate at base, placentation axile, ovules 1 or rarely 2 per locule, style straight, stigma 4-branched or ± peltate and 4-lobed (capitate and inconspicuously lobed in rudimentary gynoecium), the branches and lobes often emarginate. Fruit of 1-4 drupes (abortive carpels, if any, often persistent), these ± compressed and ± asymmetrically subglobose to ellipsoid or obovoid, rounded to cuneate at base, often with short stylar beak; pericarp in fully mature drupes with fleshy exocarp, chartaceous mesocarp, and thinly cartilaginous endocarp. Seeds solitary or rarely in pairs, ± compressedsubglobose to -ellipsoid, ± hemispherical when in pairs; testa in fully mature seeds black or reddish black, ± shiny, smooth to irregularly roughened, with thick inner layer of black, bony sclerenchyma (the sclerotesta); endosperm copious; embryo straight, hypocotyl superior, cotyledons flattened, elliptic.

Picrella , recognised herein to comprise three species, one with three varieties, is endemic to New Caledonia, occurring throughout the Grande- Terre, on the Île des Pins, and in the Loyalty Islands (including Île Walpole, which lies about 140 km SSE of Maré). It appears to be most nearly related to the New Caledonian genus Comptonella Baker f. (see HARTLEY 1983), differing mainly in its simple trichomes (vs. trichomes stellate to lepidote except in C. glabra T.G. Hartley , which is glabrous throughout), its possession (vs. apparent lack) of a floral disc, and its style, which joins the carpels laterally (vs. apically or subapically). Also, it tends to differ from Comptonella in its carpels, which in flower and fruit are distinct or very shortly connate at base (vs. carpels connate at base or up to nearly their full length).

From genera of Simaroubaceae s.l. (including Irvingiaceae , Kirkiaceae , Picramniaceae , and Surianaceae ), judging from the literature and the study of specimens at hand, Picrella differs mainly in its possession (vs. usual lack) of punctate oil glands, its opposite (vs. alternate) leaves, and its albuminous (vs. exalbuminous or nearly so) seeds with bony, sclerenchymatous (vs. fleshy to pergamentaceous) testa.

Authors placed some taxa now referable to Picrella in Euodia J.R. Forst. & G. Forst. , for which they used the variant spelling Evodia . Because quoting in each instance the misspelling used would make the literature citations complicated and cumbersome, we have used the original spelling Euodia in the relevant synonymies presented below.