| # The Families of Angiosperms |

L. Watson and M.J. Dallwitz

### Stachyuraceae J.G. Agardh

Habit and leaf form. Small trees, or shrubs, or lianas; non-laticiferous, without coloured juice. Self supporting, or climbing. Leaves persistent, or deciduous; alternate; ‘herbaceous’, or leathery; petiolate; non-sheathing; simple. Lamina entire; pinnately veined; cross-venulate. Leaves stipulate. Stipules free of one another; caducous (small, linear-lanceolate). Lamina margins serrate (or serrulate).

Leaf anatomy. The leaf lamina dorsiventral (but with a thin mesophyll). Stomata present; mainly confined to one surface (abaxial); anomocytic. The mesophyll without sclerenchymatous idioblasts; containing crystals. The crystals druses. Minor leaf veins without phloem transfer cells.

Axial (stem, wood) anatomy. Young stems with solid internodes. Pith homogeneous (of thin walled parenchyma). Secretory cavities absent. Cork cambium present; initially superficial. Nodes tri-lacunar. Primary vascular tissues in a cylinder, without separate bundles; collateral. Internal phloem absent. Cortical bundles absent. Medullary bundles absent. Secondary thickening developing from a conventional cambial ring.

The wood diffuse porous. The vessels very small; exclusively solitary. The vessel end-walls oblique; scalariform, or reticulately perforated and scalariform. The vessels without vestured pits; with spiral thickening. The axial xylem with tracheids; with fibre tracheids; without libriform fibres; without septate fibres. The fibres with spiral thickening, or without spiral thickening. The parenchyma apotracheal; wood not storied. Tyloses absent.

Reproductive type, pollination. Unisexual flowers present, or absent. Plants hermaphrodite, or polygamomonoecious.

Inflorescence, floral, fruit and seed morphology. Flowers aggregated in ‘inflorescences’; pendulous, in racemes, or in spikes. The ultimate inflorescence units racemose. Inflorescences terminal, or axillary; pendulous racemes or spikes. Flowers bi- bracteolate (the bracteoles connate); small; regular; 4 merous (throughout); cyclic; polycyclic. Floral receptacle with neither androphore nor gynophore. Free hypanthium absent.

Perianth with distinct calyx and corolla; 8; 3 whorled; isomerous. Calyx 4; 2 whorled (2+2); polysepalous; regular; much imbricate. Corolla 4; 1 whorled; polypetalous (the petals connivent); contorted (Stachyurus praecox, cf. J.D. Hooker, Bot. Mag. tab. 6631), or imbricate (?); regular. Petals sessile.

Androecium 8. Androecial members free of the perianth; free of one another; 2 whorled. Androecium exclusively of fertile stamens. Stamens 8; diplostemonous; filantherous (the filaments subulate). Anthers appearing versatile; dehiscing via longitudinal slits; introrse; tetrasporangiate. Pollen grains aperturate; 3(–4) aperturate; (tri-) colporate (occasionally 4-ruporate); 2-celled.

Gynoecium 4 carpelled. Carpels isomerous with the perianth. The pistil 1 celled, or 4 celled. Gynoecium syncarpous; eu-syncarpous; superior. Ovary 1 locular, or 4 locular (4-locular at the base, but above and for most of it length the partitions, though deeply intruded, are not united in the middle). Gynoecium shortly stylate. Styles 1; apical. Stigmas 1; obscurely 4 lobed; capitate to subpeltate; wet type; papillate; Group I type. Placentation parietal (above); axile (below). Ovules 30–50 per locule (‘numerous’); arillate; anatropous; bitegmic; crassinucellate. Outer integument contributing to the micropyle. Embryo-sac development Polygonum-type. Polar nuclei fusing prior to fertilization. Antipodal cells formed; 3; not proliferating; ephemeral. Synergids pear-shaped. Endosperm formation nuclear.

Fruit fleshy; indehiscent; a berry (rather firm and dry, 4-locular); many seeded. Seeds endospermic. Endosperm oily (and proteinaceous). Seeds small. Embryo well differentiated. Cotyledons 2 (flat). Embryo straight.

Physiology, phytochemistry. Not cyanogenic. Arbutin absent. Iridoids not detected. Proanthocyanidins present, or absent; cyanidin. Flavonols present; kaempferol and quercetin. Ellagic acid present. Aluminium accumulation not found.

Geography, cytology. Holarctic. Temperate to tropical. Eastern Asia - Himalayas to Formosa and Japan.

Taxonomy. Subclass Dicotyledonae; Crassinucelli. Dahlgren’s Superorder Theiflorae (?); Theales (?). Cronquist’s Subclass Dilleniidae; Violales. APG III core angiosperms; core eudicot; Superorder Rosanae; malvid. APG IV Order Crossosomatales.

Species about 10. Genera 1; only genus, Stachyurus.

Illustrations. • Stachyurus praecox: Bot. Mag. 108 (1882). • Stachyurus praecox: Hutchinson. • Stachyurus praecox: Chittenden.

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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