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The families of flowering plants

L. Watson and M. J. Dallwitz

Bromeliaceae Juss.

Including Tillandsieae (Tillandsiaceae) Juss.

Habit and leaf form. Herbs, or ‘arborescent’ (a few). Plants succulent (usually, more or less), or non-succulent. Perennial; with a basal aggregation of leaves (mostly acaulescent rosette plants, adapted to absorb the water which accumulates in the vase-shaped leaf rosettes — the ‘pitchers’ constituting the only habitat of certain Utricularias, utilized by specialized frogs, etc.), or with terminal aggregations of leaves, or without conspicuous aggregations of leaves (sometimes with leaves on elongated stems), or with terminal aggregations of leaves. Self supporting, or epiphytic (commonly, even growing on cacti), or climbing (rarely, e.g. in Pitcairnia). Mesophytic, or xerophytic. Leaves alternate; spiral (mostly), or distichous (some Tillandsia species); usually leathery and fleshy, or modified into spines (usually thick and stiff, with internal water storage tissue, often spine-tipped); usually imbricate; sessile; sheathing. Leaf sheaths with free margins. Leaves simple. Lamina entire; linear, or lanceolate, or ovate, or subulate; parallel-veined; without cross-venules. Leaves exstipulate. Lamina margins entire, or serrate (often serrate-spiniferous).

General anatomy. Plants with silica bodies.

Leaf anatomy. Epidermis containing silica bodies (one per cell, small, round, embedded in the thick inner periclinal walls). Stomata present; paracytic (or with four additional subsidiaries on the outside). Hairs present. Complex hairs present; peltate (involved in water absorption). The mesophyll containing mucilage cells (with raphides); containing crystals. The crystals raphides. Foliar vessels present, or absent; with scalariform end-walls. Minor leaf veins without phloem transfer cells (2 genera).

Axial (stem, wood) anatomy. Secondary thickening absent. The axial xylem with vessels, or without vessels.

The vessel end-walls scalariform.

Root anatomy. Root xylem with vessels; vessel end-walls scalariform, or simple (mostly scalariform).

Reproductive type, pollination. Unisexual flowers absent. Plants hermaphrodite (usually). Floral nectaries present. Nectar secretion from the gynoecium (via septal nectaries). Pollination entomophilous, or ornithophilous (commonly by hummingbirds), or cheiropterophilous, or anemophilous (rarely — Navia).

Inflorescence, floral, fruit and seed morphology. Flowers aggregated in ‘inflorescences’; in racemes, or in spikes, or in heads (or thyrses). The ultimate inflorescence units seemingly racemose. Inflorescences not scapiflorous (the axes leafy to bracteate); simple or compound spikes, racemes, thyrses or heads. Flowers bracteate (the bracts distichous, often conspicuous and brightly coloured); regular, or somewhat irregular; 3 merous; cyclic; pentacyclic. Perigone tube present, or absent (the flowers epigynous to hypogynous).

Perianth with distinct calyx and corolla; 6; free, or joined; 2 whorled; isomerous; without spots; different in the two whorls (the outer members generally much smaller, hyaline or greenish, the inner members petaloid); green, white, yellow, red, violet, and blue. Calyx 3; 1 whorled (i.e. the outer perianth whorl); polysepalous, or gamosepalous; imbricate. Corolla 3; 1 whorled; appendiculate (with coronal structures and/or paired, basal nectary scales), or not appendiculate; polypetalous, or gamopetalous (sometimes basally connate). Corolla lobes markedly longer than the tube. Corolla imbricate, or contorted; green, or white, or yellow, or orange, or red, or blue (or violet).

Androecium 6. Androecial members free of the perianth (when the perianth members are free), or adnate (when they are connate); free of one another, or coherent (sometimes with connate filaments); 2 whorled (3+3). Androecium exclusively of fertile stamens. Stamens 6; diplostemonous; alterniperianthial. Anthers dorsifixed (peltate), or basifixed; dehiscing via longitudinal slits; introrse. Endothecium developing fibrous thickenings. The endothecial thickenings spiral. Microsporogenesis successive. Anther wall of the ‘monocot’ type. Tapetum glandular. Pollen shed in aggregates (e.g. Cryptanthus, Hohenbergia), or shed as single grains; when aggregated, in tetrads. Pollen grains aperturate; sulcate (mostly), or foraminate (tri- or poly-, in a few Bromelioideae); 2-celled (recorded in 10 genera).

Gynoecium 3 carpelled. Carpels isomerous with the perianth. The pistil 3 celled. Gynoecium syncarpous; synstylovarious; superior to inferior. Ovary 3 locular. The ‘odd’ carpel anterior. Gynoecium stylate. Styles 1; apical. Stigmas 3; commissural; wet type, or dry type; papillate; Group II type and Group III type. Placentation axile. Ovules 5–50 per locule (‘several to many’); anatropous; bitegmic; crassinucellate. Outer integument 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 helobial. Embryogeny asterad.

Fruit fleshy, or non-fleshy; dehiscent, or indehiscent; a capsule, or a berry. Capsules when produced, septicidal (usually), or loculicidal (rarely), or septicidal and loculicidal. Gynoecia of adjoining flowers combining to form a multiple fruit, or not forming a multiple fruit. The multiple fruits sometimes coalescing. Seeds endospermic. Endosperm peripherally oily. Seeds winged (rarely, or ‘with a pappus-like process’), or wingless. Seeds with starch. Embryo well differentiated. Cotyledons 1. Embryo achlorophyllous (Pitcairnia xanthifolia); straight (cylindrical). Testa without phytomelan.

Seedling. Hypocotyl internode present to absent. Seedling collar not conspicuous. Cotyledon hyperphyll elongated, or compact; assimilatory, or non-assimilatory; when elongated, more or less circular in t.s. (e.g. Vriesia). Coleoptile absent. Seedling cataphylls absent. First leaf dorsiventral. Primary root ephemeral (or lacking, in Tillandsioideae).

Physiology, phytochemistry. CAM. CAM recorded directly in Abromeitiella, Acanthostachys, Aechmea, Ananas, Araeocassus, Billbergia, Bromelia, Canistrum, Cryptanthus, Deuterocohnia, Dyckia, Encholirium, Guzmania, Hechtia, Hohenbergia, Hoplophytum, Neoglaziovia, Neoregelia, Nidularium, Orthophytum, Portea, Puya, Quesnelia, Streptocalyx, Tillandsia (including non-succulents), Wittrockia. Anatomy non-C4 type (Ananas). Accumulated starch other than exclusively ‘pteridophyte type’. Not cyanogenic. Alkaloids absent (10 species — but usually accumulating proteolytic enzymes in some parts of the plant). Saponins/sapogenins present (at least sometimes), or absent (?). Proanthocyanidins absent (11 genera). Flavonols present, or absent (mostly); when present, quercetin, or kaempferol and quercetin. Ellagic acid absent. Sieve-tube plastids P-type; type II.

Geography, cytology. Sub-tropical and tropical. America and West Indies, save for one species in West Africa. X = 8–29 (often 25).

Taxonomy. Subclass Monocotyledonae. Dahlgren et al. Superorder Bromeliiflorae; Bromeliales. APG 3 core angiosperms; Superorder Lilianae; commelinid Monocot; Order Poales.

Species about 3000 (estimates having increased greatly in recent years). Genera 50–58 (with complicated synonymy); Abromeitiella, Acanthostachys, Aechmea, Alcantarea, Ananas, Androlepis, Araeococcus, Ayensua, Billbergia, Brewcaria, Brocchinia, Bromelia, Canistropsis, Canistrum, Catopsis, Chevaliera, Connellia, Cottendorfia, Cryptanthus, Deinacanthon, Deuterocohnia, Disteganthus, Dyckia, Edmundoa, Encholirium, Fascicularia, Fernseea, Fosterella, Glomeropitcairnia, Greigia, Guzmania, Hechtia, Hohenbergia, Hohenbergiopsis, Lamprococcus, Lindmania, Lymania, Macrochordion, Mezobromelia, Navia, Neoglaziovia, Neoregelia, Nidularium, Ochagavia, Ortgiesia, Orthophytum, Pepinia, Pitcairnia, Platyaechmea, Podaechmea, Portea, Pseudaechmea, Pseudananas, Puya, Quesnelia, Racinaea, Ronnbergia, Steyerbromelia, Streptocalyx, Tillandsia, Ursulaea, Vriesia, Werhauia, Wittrockia.

Economic uses, etc. In addition to pineapple (Ananas comosus), the family provides ‘vegetable hair’ used for upholstery (Tillandsia), cordage and fabric fibres (Neoglaziovia, Aechmea), and many horticultural ornamentals.

Illustrations. • Technical details: Ananas, Dyckia. • Technical details: Bromelia, Billbergia, Tillandsia. • Dyckia remotiflora: as D. rariflora, Bot. Reg. 1782, 1836. • Pitcairnia heterophylla: as Puya, Bot. Reg. xxvi, 71 (1840). • Puya caerulea: Bot. Reg. xxvi, 11 (1840). • Vriesia psittacina: Bot. Reg. 29 (10), 1843. • Tillandsia dianthoidea: as T. stricta, Bot. Reg. 1338 (1830). • Tillandsia geminiflora: as T. rubida, Bot. Reg. 63 (1842).

The descriptions are offered for casual browsing only. We strongly advise against extracting comparative information from them. 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: 22nd August 2016.’.