The families of flowering plants
Including Dichrolepideas (Dichrolepidaceae) Welw.
Habit and leaf form. Herbs. Leaves well developed. Perennial (usually small); with a basal aggregation of leaves. Helophytic. Leaves alternate; spiral (usually), or distichous (rarely); flat, or folded, or terete (or canaliculate); herbaceous, or leathery, or membranous; sessile; sheathing (but at the base only). Leaf sheaths with free margins. Leaves simple; epulvinate. Lamina entire; linear (grasslike); parallel-veined; without cross-venules. Leaves eligulate. Lamina margins entire.
General anatomy. Plants with silica bodies (in the subepidermal cells in Paepalanthus), or without silica bodies (mostly). Chlorenchyma without peg cells.
Leaf anatomy. Epidermis without silica bodies. Stomata present; paracytic. Guard-cells grass type. The mesophyll not containing mucilage cells; containing crystals. The crystals druses, or solitary-prismatic (or styloids no raphides). Foliar vessels present; with scalariform end-walls, or with reticulately perforated end-walls and with scalariform end-walls. Minor leaf veins without phloem transfer cells (Eriocaulon).
Axial (stem, wood) anatomy. Secondary thickening absent.
The vessel end-walls scalariform and simple (mostly simple).
Root anatomy. Root xylem with vessels; vessel end-walls scalariform and simple (mostly simple).
Reproductive type, pollination. Unisexual flowers present. Plants monoecious (usually), or dioecious (rarely). Female flowers without staminodes. Gynoecium of male flowers pistillodial to vestigial. Floral nectaries present (Eriocaulon), or absent (the rest). Nectar secretion in Eriocaulon, from the perianth (from the mouth or the inside of the perigone tube). Pollination anemophilous, or entomophilous.
Inflorescence, floral, fruit and seed morphology. Flowers aggregated in inflorescences; in heads; not in spikelets. The ultimate inflorescence units racemose. Inflorescences scapiflorous; terminal; with involucral bracts; pseudanthial. Flowers bracteate; minute, or small; regular to very irregular; when irregular, zygomorphic. The floral irregularity when present, involving the perianth and involving the androecium (not K). Flowers 2 merous, or 3 merous; cyclic. Floral receptacle developing an androphore, or with neither androphore nor gynophore. Perigone tube present. Hypogynous disk absent.
Perianth with distinct calyx and corolla, or sepaline (the corolla sometimes small, vestigial or missing in female flowers); 4–6; joined; 2 whorled (usually), or 1 whorled; isomerous; different in the two whorls. Calyx 2, or 3; 1 whorled; polysepalous, or gamosepalous (sometimes with a basal tube or spathaceous); unequal but not bilabiate (sometimes forming a spathe), or bilabiate, or regular. Corolla 2, or 3; 1 whorled; polypetalous (often, in female flowers), or gamopetalous (male flowers with a corolla tube); unequal but not bilabiate (the anterior petal sometimes larger than the lateral pair), or bilabiate, or regular.
Androecium 2–6 (2 or 4 when 2-merous, 3 or 6 when 3-merous). Androecial members adnate (to the corolla); free of one another; 1 whorled, or 2 whorled. Androecium exclusively of fertile stamens. Stamens 2, or 4, or 3, or 6; isomerous with the perianth, or diplostemonous; alternisepalous (when reduced to one whorl), or alternisepalous and oppositisepalous. Anthers basifixed; dehiscing via longitudinal slits; introrse; bisporangiate, or tetrasporangiate. Endothecium developing fibrous thickenings. The endothecial thickenings girdling. Microsporogenesis successive (probably always), or simultaneous (sometimes?). Anther wall initially with one middle layer. Tapetum glandular. Pollen grains aperturate; 5–9 aperturate (?); spiraperturate; 3-celled.
Gynoecium 2 carpelled, or 3 carpelled. The pistil 2 celled, or 3 celled. Gynoecium syncarpous; synstylovarious; superior. Ovary 2 locular, or 3 locular; sessile to stipitate. Styles 1–3; free to partially joined; apical. Stigmas 2, or 3; dorsal to the carpels, or commissural (then with stylodium-like appendages inserted between the true stigmas); dry type; non-papillate; Group II type. Placentation apical. Ovules 1 per locule; pendulous; non-arillate; orthotropous; bitegmic; tenuinucellate. Outer integument contributing to the micropyle (Syngonanthus), or not 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, or helobial. Embryogeny asterad.
Fruit non-fleshy; dehiscent; a capsule. Capsules loculicidal. Seeds copiously endospermic. Endosperm not oily. Seeds with starch. Embryo rudimentary at the time of seed release. Embryo lenticular. Testa without phytomelan (?).
Seedling. Hypocotyl internode absent. Cotyledon hyperphyll compact; non-assimilatory. Coleoptile absent. First leaf dorsiventral. Primary root ephemeral (virtually absent).
Physiology, phytochemistry. Anatomy non-C4 type (Eriocaulon). Accumulated starch other than exclusively pteridophyte type. Not cyanogenic. Alkaloids absent (one species). Proanthocyanidins absent. Flavonols absent. Ellagic acid absent. Sieve-tube plastids P-type; type II.
Geography, cytology. Sub-tropical and tropical (mostly), temperate (a few). Mainly tropical/subtropical, concentrated in South America. X = 8, 10.
Taxonomy. Subclass Monocotyledonae. Dahlgren et al. Superorder Commeliniflorae; Commelinales. APG 3 core angiosperms; Superorder Lilianae; commelinid Monocot; Order Poales.
Species 1150. Genera 11; Actinocephalus, Blastocaulon, Eriocaulon, Llachnocaulon, Leiothrix, Mesanthemum, Paepalanthus, Philodice, Rhodonanthus, Syngonanthus, Tonina.
Economic uses, etc. Furnishes a few species sold as decorative everlastings.
Illustrations. • Le Maout and Decaisne: Eriocaulon. • Mesanthemum radicans: Thonner. • Tonina fluviatilis: Lindley. • Eriocaulon septangulare (B. Ent., 1835). • Actinocephalus compactus, as Paepalanthus: Hook. Ic. Pl. 5–6 (1842–3). • Actinocephalus polyanthus, as Paepalanthus speciosus: Hook. Ic. Pl. 5–6 (1842–3). • Paepalanthus uncinatus: Hook. Ic. Pl. 5–6 (1842–3).
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: 24th October 2017. delta-intkey.com/angio’.