| # The Families of Angiosperms |

L. Watson and M.J. Dallwitz

### Rousseaceae Hook. f. ex Benth.

Including Carpodetaceae.

Habit and leaf form. Small trees, or shrubs, or lianas; laticiferous (Abrophyllum), or non-laticiferous, without coloured juice (?). Plants green and photosynthesizing. To 8 m high. Leptocaul. Mesophytic (in warm temperate and subtropical rain forest, along small water courses). Leaves persistent; medium-sized (about 10–20 cm long, 4–10 cm wide); alternate, or opposite (Roussea); spiral, or distichous; flat; ‘herbaceous’ to leathery; shortly petiolate (petioles 2–4 cm long); non-sheathing; simple; epulvinate. Lamina entire; elliptic to ovate, or lanceolate; pinnately veined; cross-venulate; attenuate to the base. Leaves exstipulate. Lamina margins distally shortly glandular- 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. Unisexual flowers present, or absent. Plants hermaphrodite, or gynomonoecious; homostylous. Floral nectaries present. Nectar secretion from the disk (but the disk inconspicuous).

Inflorescence, floral, fruit and seed morphology. Flowers solitary, or aggregated in ‘inflorescences’; minutely bracteate 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, or absent; intrastaminal (inconspicuous); annular.

Perianth with distinct calyx and corolla; (8–)10(–12); 2 whorled; isomerous. Calyx (4–)5(–7); 1 whorled; very short, polysepalous, or gamosepalous (basally fused); toothed (the lobes deciduous). Calyx lobes markedly longer than the tube. Calyx tubular; regular; not persistent; non-accrescent. Corolla (4–)5(–8); 1 whorled; polypetalous, or gamopetalous (basally). Corolla lobes about the same length as the tube to markedly longer than the tube. Corolla valvate (the petals often ultimately spreading); regular; white, or yellow (-ish), or orange; plain; deciduous; non-accrescent. Petals sessile; entire.

Androecium (4–)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 dorsifixed, or 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(–7) carpelled. The pistil (3–)5(–7) celled. Gynoecium syncarpous; eu-syncarpous; superior, or partly inferior (Carpodetus). Ovary 5 locular; sessile. Gynoecium shortly to long- stylate. Styles 1; attenuate from the ovary; apical; shorter than the ovary to much longer than the ovary. Stigmas 1; 1 lobed, or 5 lobed; capitate. Placentation axile, or axile to apical. Ovules 10–50 per locule (i.e., many); funicled; pendulous, or horizontal; apotropous; biseriate; non-arillate; anatropous.

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

Physiology, phytochemistry. Polyacetylenes not found.

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 III core angiosperms; core eudicot; Superorder Asteranae; campanulid. APG IV Order Asterales.

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

History of the encoded description. This description was prepared by LW in 2009 with reference mainly to Abrophyllum, and the morphology needs more 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). • Le Maout and Decaisne: Abrophyllum ornans. • Abrophyllum ornans, fruiting: photo, P. Woodard. • Carpodetus serratus: Hook. Ic. Pl. V (1842). • Roussea simplex: Endlicher, Ic. Gen. Plantarum (1838). • Roussea simplex: Baillon, Hist. des Plantes 3 (1872).

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: 8th June 2026. delta-intkey.com’.

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