The families of flowering plants
Habit and leaf form. Rather small trees, or shrubs; leptocaul (with short- and long-shoots). Leaves deciduous; alternate; petiolate; non-sheathing; simple. Lamina entire; pinnately veined. Leaves exstipulate. Lamina margins serrate, or dentate.
Leaf anatomy. Stomata present; anomocytic.
Lamina dorsiventral. The mesophyll without sclerenchymatous idioblasts; containing calcium oxalate crystals. The mesophyll crystals druses.
Stem anatomy. Cork cambium present; initially deep-seated. Nodes unilacunar (with 79 traces). Internal phloem absent. Secondary thickening developing from a conventional cambial ring. Included phloem absent. Xylem with tracheids; with vessels. Vessel end-walls oblique; scalariform, or reticulately perforated. Wood parenchyma apotracheal (in terminal bands). Sieve-tube plastids S-type.
Reproductive type, pollination. Plants hermaphrodite, or andromonoecious. Floral nectaries absent. Pollination anemophilous.
Inflorescence, floral, fruit and seed morphology. Flowers solitary in the axils of 612 closely crowded, early season bracts on the short-shoots; bracteate; bracteolate (the lower flowers often having one or two tiny prophylls), or ebracteolate; cyclic. Floral receptacle flattened. Hypogynous disk absent.
Androecium 7–20(–50) (more or less many). Androecial members free of one another; 1 whorled. Androecium exclusively of fertile stamens. Stamens 7–20(–50); filantherous (the filaments short, slender or slightly expanded). Anthers elongate, red, basifixed; non-versatile; dehiscing via longitudinal slits, or dehiscing by longitudinal valves; latrorse; tetrasporangiate; appendaged. The anther appendages apical (by prolongation of the connective). Pollen shed as single grains. Pollen grains aperturate; 3 aperturate, or 5–7 aperturate, or 8–20 aperturate (to many); colpate, or rugate; 2-celled.
Gynoecium 6–18 carpelled; apocarpous; eu-apocarpous; superior. Carpel incompletely closed; non-stylate (stipitate); with a decurrent stigma, which does not reach the hooded summit because of asymmetric growth of the carpel after anthesis; 1–3(–4) ovuled. Placentation marginal (or submarginal). Ovules anatropous; bitegmic; crassinucellate. Endosperm formation cellular.
Fruit non-fleshy; an aggregate. The fruiting carpel indehiscent; small, samaroid (stipitate, with papery pericarp). Seeds copiously endospermic. Endosperm oily (and proteinaceous). Embryo weakly differentiated (and tiny). Cotyledons 2 (poorly differentiated).
Seedling. Germination phanerocotylar. Seedling cataphylls present (two, but poorly differentiated).
Physiology, biochemistry. Not cyanogenic. Iridoids not detected. Proanthocyanidins present; cyanidin. Ellagic acid absent. Arbutin absent. Saponins/sapogenins present (triterpenoid).
Geography, cytology. Holarctic. Temperate. Assam, China, Japan. 2n = 28.
Taxonomy. Subclass Dicotyledonae; Crassinucelli. Dahlgrens Superorder Rosiflorae; Trochodendrales. Cronquists Subclass Hamamelidae; Hamamelidales. APG 3 core angiosperms; peripheral eudicot; Superorder Ranunculanae; Order Ranunculales.
Species 2. Genera 1; only genus, Euptelea.
This description is offered for casual browsing only. We strongly advise against extracting comparative information from it. This is much more easily achieved using 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).
Cite this publication as: ‘Watson, L., and Dallwitz, M.J. 1992 onwards. The families of flowering plants: descriptions, illustrations, identification, and information retrieval. Version: 19th December 2012. http://delta-intkey.com’.