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The families of flowering plants

L. Watson and M.J. Dallwitz

Rousseaceae Hook. f. ex Benth.

Including Carpodetaceae.

Habit and leaf form. Small trees, or shrubs; laticiferous (Abrophyllum), or non-laticiferous (?). To 8 m high. Leptocaul. Mesophytic (in warm temperate and subtropical rain forest, along small water courses). Leaves medium-sized (about 10–20 cm long, 4–10 cm wide); alternate; spiral; flat; ‘herbaceous’ (thin); shortly petiolate (petioles 2–4 cm long); non-sheathing; not gland-dotted; simple; epulvinate. Lamina entire; elliptic to ovate, or lanceolate; pinnately veined; attenuate at the base. Leaves exstipulate. Lamina margins distally shortly dentate, or serrate; flat. Leaf development not ‘graminaceous’. Domatia occurring in the family (recorded in Carpodetus); manifested as pockets.

General anatomy. Plants with laticifers (Abrophyllum), or without laticifers (?). The laticifers of Abrophyllum in stems (there being in the pericycle a ring of laticiferous sacs consisting of longitudinal rows of vertically elongated cells). Plants with ‘crystal sand’ (in the leaves of Abrophyllum), or without ‘crystal sand’ (the rest?).

Leaf anatomy. The leaf lamina dorsiventral (with a single palisade layer in Abrophyllum). Stomata present; mainly confined to one surface (abaxial); “with pairs of small guard-cells nearly circular in outline” (Metcalfe and Chalk). Hairs present; eglandular and glandular (the latter with short, sunken stalks and unicellular heads in Abrophyllum).

Axial (stem, wood) anatomy. Primary vascular tissues in a cylinder, without separate bundles; collateral.

Reproductive type, pollination. Plants hermaphrodite; homostylous. Floral nectaries present. Nectar secretion from the disk (but the disk inconspicuous).

Inflorescence, floral, fruit and seed morphology. Flowers aggregated in ‘inflorescences’; in corymbs and in panicles. The ultimate inflorescence units cymose. Inflorescences terminal and axillary; terminal or axillary corymbose panicles, these irregulary dichotomous and much shorter than the leaves. Flowers small (4–5 mm long); regular; 5(–6) merous; tetracyclic. Free hypanthium absent. Hypogynous disk present; intrastaminal (inconspicuous); annular.

Perianth with distinct calyx and corolla; 10–12; 2 whorled; isomerous. Calyx 5(–6); 1 whorled; very short, gamosepalous; toothed (the lobes deciduous); tubular; regular; non-accrescent. Corolla 5(–6); 1 whorled; polypetalous; valvate (the petals ultimately spreading); regular; yellow (-ish); plain; deciduous; non-accrescent. Petals sessile; entire.

Androecium 5(–6). Androecial members free of the perianth; all equal; free of one another; 1 whorled. Stamens 5(–6); isomerous with the perianth; oppositisepalous; alternating with the corolla members; filantherous (with very short filaments). Anthers basifixed; non-versatile; dehiscing via longitudinal slits; introrse. Pollen shed in aggregates (in Carpodetus), or shed as single grains (?); when in aggregates, in tetrads (Carpodetus).

Gynoecium 5 carpelled. Carpels isomerous with the perianth, or reduced in number relative to the perianth. The pistil 5 celled. Gynoecium syncarpous; eu-syncarpous; superior. Ovary 5 locular; sessile. Gynoecium shortly stylate. Styles 1; attenuate from the ovary; apical. Stigmas 1; 5 lobed. Placentation axile. Ovules 10–50 per locule (i.e., many); funicled; horizontal; apotropous; biseriate; non-arillate; anatropous.

Fruit fleshy; indehiscent; a berry (this about 8–12 mm long, ovoid, black). Seeds endospermic. Endosperm oily (and fleshy). Seeds small (subglobose, with a deeply latticed testa). Embryo very small, but well differentiated. Cotyledons 2. Embryo straight.

Geography, cytology. Paleotropical, Australian, and Antarctic. Warm temperate and sub-tropical. Eastern Australia (Abrophyllum), New Zealand (Carpodetus), Mauritius (Roussea).

Taxonomy. Subclass Dicotyledonae; Tenuinucelli. Dahlgren’s Superorder Rosiflorae; Saxifragales. Cronquist’s Subclass Rosidae; Rosales. APG 3 core angiosperms; core eudicot; Superorder Asteranae; campanulid; Order Asterales.

Species 3. Genera 3; Abrophyllum (A. ornans), Carpodetus (C. serratus), Roussea.

Quotations This description was prepared by LW in 2009 with reference mainly to Abrophyllum, and the morphology needs checking against Roussea and Carpodetus. It also lacks information on anatomy, anther development, pollen, phytochemistry and (especially) embryology. For example, if the family is really “Asterid” (i.e., Tenuinucelli, = Sympetalae), they are probably tenuinucellate with unitegmic ovules (etc.).

Illustrations. • Abrophyllum ornans: Hook. Ic. Pl. 14 (1880–82). • Technical details: Abrophyllum ornans. • Abrophyllum ornans, fruiting: photo, P. Woodard. • Carpodetus serratus: Hook. Ic. Pl. V (1842).

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.’.