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The families of flowering plants

L. Watson and M.J. Dallwitz

Oceanopapaveraceae auct., nomen nudum

~ Tiliaceae, Capparidaceae, Malvaceae, etc.

Habit and leaf form. Virgate shrubs (with leaves clustered on short-shoots); without essential oils. Without conspicuous aggregations of leaves; to 1 m high. Leptocaul. Xerophytic. Not heterophyllous. Leaves evergreen; small (about 5–26 mm long); alternate; spiral; flat; leathery; not imbricate; very shortly petiolate; non-sheathing; gland-dotted; simple; epulvinate. Lamina dissected to entire (usually more or less lobed or lobulate); not conspicuously asymmetric; linear; usually more or less pinnatifid; one-veined; attenuate at the base. Leaves stipulate. Stipules intrapetiolar; free of one another; small, subulate; caducous (leaving scars). Lamina margins entire; flat. Leaf development not ‘graminaceous’.

Leaf anatomy. The leaf lamina dorsiventral. Epidermis without crystal idioblasts. Abaxial epidermis not papillose. Mucilaginous epidermis absent. Stomata present; mainly confined to one surface (abaxial); anomocytic. Hairs present; glandular, or eglandular and glandular; unicellular and multicellular. Unicellular hairs simple. Multicellular hairs uniseriate and multiseriate; branched and simple. Complex hairs present; capitate (always present), or stellate and capitate. Adaxial hypodermis absent. Lamina without secretory cavities (but exhibiting elongated secretory cells with dark-staining contents (interpreted as ‘myrosin cells’ by Schmid et al.), in several rows abaxial to the midvein). The mesophyll containing mucilage cells (and seemingly the epidermis as well); seemingly without crystals. Midrib conspicuous.

Axial (stem, wood) anatomy. Young stems cylindrical; with solid internodes. Secretory cavities present (the pith containing a single, large secretory canal); with mucilage (?). Nodes unilacunar. Primary vascular tissues comprising a ring of bundles; collateral. Secondary thickening developing from a conventional cambial ring. Primary medullary rays narrow.

The wood diffuse porous. The vessel end-walls oblique; simple. The vessels without vestured pits. The axial xylem without fibre tracheids; with libriform fibres (and vasicentric tracheids). The parenchyma apotracheal and paratracheal (with apotracheal ‘bands’ recorded only in the later years of growth). The secondary phloem stratified into hard (fibrous) and soft (parenchymatous) zones. Tile cells present. The wood partially storied.

Reproductive type, pollination. Unisexual flowers absent. Plants hermaphrodite; not viviparous; homostylous. Floral nectaries present (trichomic). Nectar secretion from the disk (from cavities axillary to the petals). Pollination entomophilous, or ornithophilous, or cheiropterophilous (?); mechanism unspecialized.

Inflorescence, floral, fruit and seed morphology. Flowers solitary and aggregated in ‘inflorescences’; when solitary, axillary; when clustered, in racemes. The ultimate inflorescence units racemose. Inflorescences axillary (to the leaves of either long- or short-shoots); mostly comprising shortly pedunculate clusters of 2–3 flowers. Flowers bracteate (the bracts very short, linear, subulate); ebracteolate; small to medium-sized (about 7–10 mm long); regular; cyclic; tetracyclic. Floral receptacle developing an androphore; not markedly hollowed. Free hypanthium absent. Hypogynous disk absent.

Perianth with distinct calyx and corolla; 8 (usually), or 10 (sometimes); free; 2 whorled; isomerous. Calyx 4(–5); 1 whorled; polysepalous; regular; neither appendaged nor spurred; non-fleshy; not persistent; valvate. Corolla 4(–5); 1 whorled; appendiculate (the petals each with a basal-adaxial, hairy cushion or scale); polypetalous; imbricate and crumpled in bud; regular; yellow; plain; not fleshy; non-accrescent. Petals slightly clawed; entire (with slightly iregular margins).

Androecium 30–42–50 ((30–)40–50, fewer in pentamerous flowers). Androecial members branched (with 4(–5) trunk bundles); maturing centrifugally; free of the perianth; all equal; free of one another (i.e., not detectably bundled); 1 whorled. Androecium exclusively of fertile stamens. Stamens 30–42–50 ((30–)40–50, fewer in pentamerous flowers); polystemonous; both alternating with and opposite the corolla members; erect in bud; filantherous (the filaments filiform). Anthers separate from one another; dorsifixed; versatile (?); dehiscing via longitudinal slits; tetrasporangiate. Endothecium developing fibrous thickenings. Anther epidermis persistent. Tapetum glandular. Pollen shed as single grains; without viscin strands. Pollen grains aperturate; 3 aperturate; (tri-) colporate; muricate; lophate; 2-celled.

Gynoecium 2(–3) carpelled. Carpels reduced in number relative to the perianth. The pistil 1 celled, or 2 celled, or 3 celled, or 1 and 2 celled, or 1 and 3 celled. Gynoecium syncarpous; eu-syncarpous; superior. Ovary 2 locular, or 3 locular, or 1 and 2 locular, or 1 and 3 locular (2(–3) plurilocular above and below, but in the placental region unilocular to plurilocular or only plurilocular); very shortly stipitate, or sessile to subsessile. Gynoecium stylate. Styles 1; attenuate from the ovary; apical; much longer than the ovary. Stylar canal present. Stigmas 1; dorsal to the carpels; slightly 2 lobed, or 2(–3) lobed (?); truncate; dry type; non-papillate. Placentation when/ where unilocular, parietal (Schmid et al.’s illustration of a mid-carpellary section shows a unilocular ovary with two deeply intrusive parietal placentae); when/ where bilocular axile, or axile and parietal. Ovules differentiated; in the single cavity 10–20; 4–9 per locule (? — ‘about 7’); funicled; pendulous; epitropous; with ventral raphe, or with lateral raphe (?); superposed, or biseriate; non-arillate; anatropous (Tirel et al.), or campylotropous (Schmid et al.); bitegmic; crassinucellate. Outer integument contributing to the micropyle. Endosperm formation cellular.

Fruit non-fleshy; dehiscent (wekly), or indehiscent, or lomentaceous (? — elongated, deeply torulose and lomentlike, but breakup/ dehiscence not recorded in life — valvular dehiscence limited to the fruit apex seems to have been seen only in herbarium specimens); capsular-indehiscent, or a siliqua (?). Dispersal unit the seed, or the fruit (?). Fruit 1–7(–12) seeded (with 1 pendent seed in each segment). Seeds endospermic (the endosperm fleshy). Endosperm oily. Seeds small (about 1.6 mm long). Seeds without starch. Cotyledons 2 (with numerous secretory cells); flat. Embryo straight. Testa non-operculate; smooth; without phytomelan; black, or brown.

Physiology, phytochemistry. C3. Anatomy non-C4 type. Mustard-oils absent (if the secretory elements are not really ‘myrosin cells’). Alkaloids absent.

Geography, cytology. Paleotropical. Tropical. New Caledonia. 2n=14. Supposed basic chromosome number of family: 7.

Taxonomy. Subclass Dicotyledonae; Crassinucelli. Dahlgren’s Superorder Malviflorae, or Violiflorae (?); if Malviflorae, Malvales; if Violiflorae, Capparales. Cronquist’s Subclass Dilleniidae; Violales, or Capparales (?). APG 3 core angiosperms; core eudicot; Superorder Rosanae; malvid; Order unassigned (? - presumably Malvales or Brassicales).

Species 1 (Oceanopapaver neocaledonicum Guillaumin). Genera 1; Oceanopapaver only.

General remarks. Variously assigned to Tiliaceae or Capparidaceae, formerly sometimes to Papaveraceae or Cistaceae. This description (organized at Una Smith’s instigation by her and Les Watson) is taken mainly from the detailed account and illustrations of Schmid et al. (1984, who confidently referred it to Capparidaceae), plus Geesink et al (1981), Tirel (1996), and Tirel et al (1996). However, the genus Oceanopapaver has more recently been synonymized, with the support of dubious evidence from chloroplast DNA sequences, under Corchorus in the Malvaceae-Grewioideae!.

We advise against extracting comparative information from the descriptions. This is much more easily achieved using the DELTA data files or the interactive key, which allows access to the character list, illustrations, full and partial descriptions, diagnostic descriptions, differences and similarities between taxa, lists of taxa exhibiting or lacking specified attributes, distributions of character states within any set of taxa, geographical distribution, genera included in each family, and classifications (Dahlgren; Dahlgren, Clifford, and Yeo; Cronquist; APG). See also Guidelines for using data taken from Web publications.

Cite this publication as: ‘Watson, L., and Dallwitz, M.J. 1992 onwards. The families of flowering plants: descriptions, illustrations, identification, and information retrieval. Version: 13th March 2017.’.