Iridaceae Juss.
Including Gladiolaceae Rafin., Hewardiaceae Nak., Isophysidaceae Takhtajan, Spathaceae Dulac
Excluding Geosiridaceae
Habit and leaf form. Herbs, or shrubs (rarely). Perennial; with a basal aggregation of leaves, or with neither basal nor terminal aggregations of leaves; rhizomatous, or cormous, or bulbaceous (a few). Helophytic to xerophytic. Leaves evergreen, or deciduous; alternate; usually distichous; flat, or terete; ‘herbaceous’, or leathery; sessile, or petiolate; sheathing. Leaf sheaths with free margins. Leaves foetid (sometimes), or without marked odour; edgewise to the stem (usually), or with ‘normal’ orientation; simple; epulvinate. Lamina entire; linear, or lanceolate; parallel-veined; without cross-venules. Leaves eligulate. Lamina margins entire. Leaves with a persistent basal meristem, and basipetal development.
General anatomy. Accumulated starch other than exclusively ‘pteridophyte type’.
Leaf anatomy. Stomata present; anomocytic.
Lamina dorsiventral, or isobilateral, or centric; with secretory cavities. Secretory cavities containing mucilage. The mesophyll not containing mucilage cells; containing calcium oxalate crystals. The mesophyll crystals solitary-prismatic. Minor leaf veins without phloem transfer cells (Iris). Vessels mostly absent.
Stem anatomy. Secretory cavities present; with mucilage. Secondary thickening absent, or anomalous (in Aristea, Klattia, Nivenia, Witsenia); when present, from a single cambial ring. Xylem without vessels (usually), or with vessels (Sisyrinchium). Vessel end-walls in Sisyrinchium, scalariform and simple (mostly simple). Sieve-tube plastids P-type; type II.
Root anatomy. Root xylem with vessels. Vessel end-walls scalariform (mostly), or scalariform and simple, or simple (Sisyrinchium).
Reproductive type, pollination. Unisexual flowers absent. Plants hermaphrodite. Floral nectaries present (mostly), or absent. Nectar secretion from the perianth (mostly, from nectaries at the tepal bases), or from the gynoecium (septal nectaries in Ixioideae). Entomophilous, or ornithophilous, or anemophilous (rarely).
Inflorescence, floral, fruit and seed morphology. Flowers solitary, or aggregated in ‘inflorescences’; in panicles, in cymes, in spikes, in umbels, and in corymbs. The terminal inflorescence unit (when more than one-flowered) cymose, or racemose. Inflorescences nearly always scapiflorous (but some with the inflorescence reduced to a single, almost sessile flower); terminal; panicles, thyrses, cymes, spikes — often hard to interpret; spatheate (via one or two expanded, bladeless sheaths). Flowers bracteate; small to large; regular to very irregular; when irregular, zygomorphic; 3 merous; cyclic; tetracyclic (usually). Perigone tube present (long or short).
Perianth of ‘tepals’; 6; joined; 2 whorled; isomerous; petaloid; without spots, or spotted (commonly); similar in the two whorls, or different in the two whorls (the inner sometimes much smaller); white, or yellow, or red, or purple, or violet, or blue (or blue-green).
Androecium (2–)3. Androecial members free of the perianth, or adnate (to the perianth tube); free of one another, or coherent (the filaments often united into a basal tube); when united, 1 adelphous; 1 whorled (representing the outer whorl). Androecium exclusively of fertile stamens. Stamens (2–)3; reduced in number relative to the adjacent perianth to isomerous with the perianth; alterniperianthial (opposite the outer perianth lobes). Anthers separate from one another (usually), or cohering (sometimes, e.g. Homeria spp); basifixed; dehiscing via longitudinal slits; extrorse. The endothecial thickenings spiral. Microsporogenesis simultaneous. The initial microspore tetrads tetrahedral, or isobilateral. Pollen grains aperturate (usually), or nonaperturate; 1 aperturate (usually), or 2 aperturate; sulcate (usually), or spiraperturate, or sulculate (Tia); 2-celled.
Gynoecium 3 carpelled; partly petaloid (commonly), or non-petaloid. The pistil 3 celled (nearly always), or 1 celled (Isophysis). Gynoecium syncarpous; synstylovarious; inferior (nearly always), or superior (very rarely —Isophysis). Ovary 3 locular, or 1 locular (Isophysis). The ‘odd’ carpel anterior. Gynoecium stylate. Styles 1 (3-lobed, the lobes sometimes subdivided or often expanded and petaloid); apical. Stylar canal present. Stigmas dry type; papillate; Group II type. Placentation when unilocular (i.e. very rarely), parietal; nearly always axile. Ovules (1–)2–50 per locule (i.e. to ‘many’); arillate, or non-arillate; anatropous; bitegmic; crassinucellate. Embryo-sac development Polygonum-type. Polar nuclei fusing prior to fertilization. Antipodal cells formed; 3; not proliferating; persistent. Synergids pear-shaped, or hooked (sometimes with filiform apparatus). Endosperm formation nuclear.
Fruit non-fleshy; dehiscent; a capsule. Capsules loculicidal. Seeds endospermic. Endosperm oily. Seeds usually without starch. Cotyledons 1 (coleoptile-like). Embryo achlorophyllous (3/5), or chlorophyllous (Tritonia crocosmifolia); straight (small). Testa without phytomelan; membranous or thick.
Seedling. Hypocotyl internode present (usually short), or absent. Mesocotyl absent. Seedling collar not conspicuous. Cotyledon hyperphyll elongated, or compact; assimilatory (sometimes when elongated), or non-assimilatory; when elongated, more or less circular in t.s. Coleoptile present (e.g. Aristea), or absent. Seedling cataphylls present (e.g. Neomarica), or absent. First leaf ensiform. Primary root ephemeral.
Physiology, biochemistry. Cyanogenic, or not cyanogenic (usually). Alkaloids present (commonly), or absent. Arthroquinones detected (Gladiolus, Libertia); polyacetate derived. Proanthocyanidins present (in 3 genera), or absent (more often); when present, cyanidin and delphinidin. Flavonols present (e.g. Gladiolus), or absent (mostly); when present, kaempferol and quercetin. Ellagic acid absent. Arbutin absent. Saponins/sapogenins present, or absent. C3. C3 physiology recorded directly in Iris, Sisyrinchium. Anatomy non-C4 type (Sisyrinchium).
Geography, cytology. Holarctic, Paleotropical, Neotropical, Cape, and Australian. Temperate to tropical. Almost cosmopolitan, but lacking from frigid zones and northern Eurasia. X = 3–19 (or more).
Taxonomy. Subclass Monocotyledonae. Superorder Liliiflorae; Liliales. APG (1998) Monocot; non-commelinoid; Asparagales. Species 1800. Genera 92; Ainea, Alophia, Anomatheca, Aristea, Babiana, Barnardiella, Belamcanda, Bobartia, Calydorea, Cardenanthus, Chasmanthe, Cipura, Cobana, Crocosmia, Crocus, Cypella, Devia, Dierama, Dietes, Diplarrhena, Duthiastrum, Eleutherine, Ennealophus, Ferraria, Fosteria, Freesia, Galaxia, Geissorhiza, Gelasine, Geosiris, Gladiolus, Gynandriris, Herbertia, Hermodactylus, Hesperantha, Hesperoxiphion, Hexaglottis, Homeria, Homoglossum, Iris, Isophysis, Ixia, Kelissa, Klattia, Lapeirousia, Lethia, Libertia, Mastigostyla, Melasphaerula, Micranthus, Moraea, Nemastylis, Neomarica, Nivenia, Olsynium, Onira, Orthrosanthus, Pardanthopsis, Patersonia, Pillansia, Pseudotrimezia, Radinosiphon, Rheome, Roggeveldia, Romulea, Savannosiphon, Schizostylis, Sessilanthera, Sisyrinchium, Solenomelus, Sparaxis, Sympa, Syringodea, Tapeina, Thereianthus, Tigridia, Trimezia, Tritonia, Tritoniopsis, Tucma, Watsonia, Wisenia, Zygotritonia.
Economic uses, etc. Numerous ornamentals, plus orris root (from Iris rhizomes) and saffron dye (from Crocus stigmas).
Illustrations. • irida01.jpg. • Iris pseudacorus. • Iris sibirica. • Iris spuria. • Crocus vernus. • Technical details (Iris). • Technical details (Crocus, Tigridia). • Technical details (Lapeyrousia).
Quotations
And with its reeds the wandering stream
Reflects the
flag-flower’s golden beam
(Charlotte Smith, quoted by Ann Pratt,
‘Wild Flowers’ (1857) - Iris pseud-acorus)
Say, what impels,
amidst surrounding snow
Congeal’d, the crocus, flamy bud to glow?
Say, what retards, amidst the summer’s blaze,
Th’ autumnal
bulb, till pale, declining days
(Gilbert White, ‘Natural History of
Selbourne’, 1788 - on spring versus autumn flowering, in closely related
species of Crocus)
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).
