Eriocaulaceae Desv.
Including Dichrolepideas (Dichrolepidaceae) Welw.
Habit and leaf form. Herbs. 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’. Accumulated starch other than exclusively ‘pteridophyte type’.
Leaf anatomy. Epidermis without silica bodies. Stomata present; paracytic. Guard-cells ‘grass type’.
The mesophyll not containing mucilage cells; containing calcium oxalate crystals. The mesophyll crystals druses, or solitary-prismatic (or styloids — no raphides). Minor leaf veins without phloem transfer cells (Eriocaulon). Vessels present; end-walls scalariform, or reticulately perforated and scalariform.
Stem anatomy. Secondary thickening absent. Xylem with vessels. Vessel end-walls scalariform and simple (mostly simple). Sieve-tube plastids P-type; type II.
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). Anemophilous, or entomophilous.
Inflorescence, floral, fruit and seed morphology. Flowers aggregated in ‘inflorescences’; in heads; not in ‘spikelets’. The terminal inflorescence unit 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; 2-celled, or 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, biochemistry. Not cyanogenic. Alkaloids absent (one species). Proanthocyanidins absent. Flavonols absent. Ellagic acid absent. Anatomy non-C4 type (Eriocaulon).
Geography, cytology. Sub-tropical and tropical (mostly), or temperate (a few). Mainly tropical/subtropical, concentrated in South America. X = 8, 10.
Taxonomy. Subclass Monocotyledonae. Superorder Commeliniflorae; Commelinales. APG (1998) Monocot; Commelinoid group; Poales. Species 1150. Genera 10; Blastocaulon, Eriocaulon, Llachnocaulon, Leiothrix, Mesanthemum, Paepalanthus, Philodice, Rhodonanthus, Syngonanthus, Tonina.
Economic uses, etc. Furnishes a few species sold as decorative ‘everlastings’.
Illustrations. • Eriocaulon septangulare. • Technical details (Mesanthemum). • Technical details (Eriocaulon). • Technical details (Tonina).
Cite this publication as: ‘L. Watson and M. J. Dallwitz (1992 onwards). The Families of Flowering Plants: Descriptions, Illustrations, Identification, and Information Retrieval. Version: 14th December 2000. http://biodiversity.uno.edu/delta/’. Dallwitz (1980), Dallwitz, Paine and Zurcher (1993, 1995, 2000), and Watson and Dallwitz (1991) should also be cited (see References).
