The World Flora Online

SELECTED REFERENCES

Anderson, L. C., C. D. Zeis, and S. F. Alam. 1974. Phytogeography and possible origins of Butomus in North America. Bull. Torrey Bot. Club 101: 292--296. Stuckey, R. L. 1968. Distributional history of Butomus umbellatus (flowering-rush) in the western Lake Erie and Lake St. Clair region. Michigan Bot. 7: 134--142. Stuckey, R. L. 1994. Map of the known distribution of Butomus (flowering- rush) in North America. In: W. R. Burk and R. L. Stuckey. 1994. Ronald L. Stuckey: His Roole in the Ohio Academy of Science. Chapel Hill. P. 85. Stuckey, R. L., G. Schneider, and M. L. Roberts. 1990. Butomus umbellatus L.: Notes from the German literature and North American field studies. Ohio J. Sci. 90(2): 5--6. Tomlinson, P. B. 1982. Helobiae (Alismatidae). In: C. R. Metcalfe, ed. 1960+. Anatomy of the Monoctotyledons. 8+ vols. Oxford. Vol. 7.

Herbs, perennial, rhizomatous, stemless, glabrous; sap clear. Roots not septate. Leaves basal, emersed or rarely submersed, sessile, sheathing somewhat proximally; blade with lade: translucent markings absent, basal lobes absent; venation parallel. Inflorescences scapose umbels, erect, bracteate. Flowers bisexual, hypogynous, pedicellate; tepals persistent, 6, in 2 series, scarious; stamens 9, distinct; anthers 4-loculed, dehiscing longitudinally; pistils 6, coherent proximally, 1-loculed; placentation laminar; ovules 50. Fruits follicles. Seeds: embryo straight; endosperm absent in mature seed.

Perennial, aquatic or swamp rhizomatous herbs, usually with milky juice Flowers solitary or umbellate Leaves ensiform to orbicular Perianth 2-seriate, the outer 3 usually sepal-like, imbricate, the inner 3 petal-like and usually thin and deciduous Fruits opening by the adaxial suture Seeds numerous, without endosperm Stamens hypogynous, 8-9 or numerous; anthers basifixed, opening laterally Carpels free; ovules numerous, scattered, on the reticulately branched parietal placentas Flowers solitary or umbellate Leaves ensiform to orbicular Perianth 2-seriate, the outer 3 usually sepal-like, imbricate, the inner 3 petal-like and usually thin and deciduous Fruits opening by the adaxial suture Seeds numerous, without endosperm Stamens hypogynous, 8-9 or numerous; anthers basifixed, opening laterally Carpels free; ovules numerous, scattered, on the reticulately branched parietal placentas

Fls axillary to bracts, hypogynous, regular, perfect, trimerous; sep 3; pet 3, pink; stamens 9; pollen monosulcate; pistils 6, connate at the very base into a ring, otherwise distinct, distally unsealed, each with a short, terminal style and shortly bilobed, shortly decurrent stigma; ovules numerous, scattered over the inner surface of the carpel; fr of separate follicles; endosperm wanting; embryo straight, with a terminal cotyledon and lateral plumule; glabrous, perennial, emergent aquatic herbs from a stout, creeping, dorsiventral, edible rhizome; lvs distichous in origin at the rhizome-tip, parallel-veined, linear, erect and ± triquetrous, not differentiated into blade and petiole, but the base somewhat expanded and sheathing; scape axillary, erect, terminating in a cymose umbel subtended by 3 bracts. A single genus and species.

Herbs, perennial, aquatic or of swamps, rhizomatous, usually with milky juice. Leaves usually emersed, basal, alternate, linear to orbicular, sheathing at base, sessile, triquetrous. Flowers hermaphroditic, in terminal, long pedunculate umbels within erect scapes, long pedicellate, with 3 free bracts. Perianth segments in 2 series, outer 3 usually sepal-like, inner 3 petal-like and usually thin and deciduous. Stamens 9, free; anthers basifixed, 2-celled, opening by longitudinal slits. Carpels 6, connate at base; ovules numerous. Fruit a whorl of follicles; follicles with apical long beak. Seeds numerous, without endosperm; embryo straight.

Sepals 3, persistent Petals 3, delicate Stamens 6–9–?; filaments flattened; anthers 2-celled, dehiscing longitudinally and laterally Carpels superior, free or joined at the base, 6–?, in a whorl, unilocular; style terminal; stigma sessile; ovules ?, scattered over the ovary-wall on a reticulate placenta Perennial or annual, aquatic, swamp or marsh herbs, glabrous, usually lactiferous Rhizome short; roots short, fibrous Leaves erect or floating, basal; petiole with a sheathing base; leaf-blade entire, iridaceous, or lanceolate to orbicular with cuneate to truncate base and acute to rounded apex Inflorescence umbellate, rarely with solitary flowers; bracts 2 or 3; bracteoles several; flowers regular, bisexual Fruiting carpels finally dehiscing along the ventral suture; seeds ?, smooth, wrinkled or ridged, rarely slightly spiny, without endosperm; embryo horseshoe-shaped or straight Petals 3, delicate Stamens 6–9–?; filaments flattened; anthers 2-celled, dehiscing longitudinally and laterally Carpels superior, free or joined at the base, 6–?, in a whorl, unilocular; style terminal; stigma sessile; ovules ?, scattered over the ovary-wall on a reticulate placenta Perennial or annual, aquatic, swamp or marsh herbs, glabrous, usually lactiferous Rhizome short; roots short, fibrous Leaves erect or floating, basal; petiole with a sheathing base; leaf-blade entire, iridaceous, or lanceolate to orbicular with cuneate to truncate base and acute to rounded apex Inflorescence umbellate, rarely with solitary flowers; bracts 2 or 3; bracteoles several; flowers regular, bisexual Fruiting carpels finally dehiscing along the ventral suture; seeds ?, smooth, wrinkled or ridged, rarely slightly spiny, without endosperm; embryo horseshoe-shaped or straight

A small family, confined to the tropics or subtropics except for Butomus L. which extends across Europe and Asia. The following genus is the only one which occurs in Africa