A TAXONOMIC ACCOUNT OF UTRICULARIA LINN. FROM BANGLADESH M. OLIUR RAHMAN Bangladesh National Herbarium, Ciriakhana Road, Mirpur-1 Dhaka-1216, Bangladesh

A taxonomic account of eight species of Utricularia Linn. viz. U. aurea Lour., U. bifida Lin., U. caerulea Linn., U. gibba Linn., U. inflexa Forsk., U. minutissima Vahl, U. scandens Benj. and U. stellaris L. f. has been provided from Bangladesh. An updated nomenclature including important synonyms, habitat and distribution have been furnished under each species. A key has also been given for easy identification of the species.


Introduction
Utricularia, an insectivorous genus of the family Lentibulariaceae encompasses 214 species, and is distributed throughout the world with the greatest species richness in the tropical regions (Taylor, 1989).They are mainly characterized by carnivorous bladders, 2-lipped calyx, personate corolla and they have no true roots.The morphology of vegetative parts usually differs from other vascular plants.Rhizoids substitute the roots.The main part of the plant is represented by a stolon with usually horizontal proliferation that bears traps, leaves and, if present, inflorescence.The leaves are organs that are considered as real leaves by some morphologists, whereas some others classify them as modified parts of the stem (Taylor, 1989).Utricularia inhabits a wide range of habitats including wet grounds, ponds, lakes and other marshy areas, epiphytic conditions and seasonal deserts.
Since Utricularia was first described in the "Species Plantarum" where Linnaeus (1753) listed only seven species, it has received considerable attention from many taxonomists.Many important accounts were produced mainly based on the morphology and floristics (Kamienski, 1895;Barnhart, 1916;Taylor, 1964;Crow, 1992).However, the most significant systematic work on the genus is the excellent monograph by Taylor (1989).Although many workers have added greatly to our knowledge of the Asian species (Oliver, 1859;Gamble, 1924;Komiya, 1972;Subramanyam, 1979), the species of this genus in Bangladesh have received very little attention (Khan and Halim 1987;Uddin et al. 2000).
This paper is based on the materials housed at the Bangladesh National Herbarium and the previous works (Clarke 1884, Prain 1903, Khan andHalim l. c.) relating to the Bangladeshi species of Utricularia.Most of the previous works were confined only to the incomplete list of species without providing any taxonomic account.The present paper deals with the detailed account of eight Utricularia species of Bangladesh, namely, U. aurea Lour., U. bifida Lin., U. caerulea Linn., U. gibba Linn., U. inflexa Forsk., U. minutissima Vahl, U. scandens Benj.and U. stellaris L. f.The dichotomous bracket key has been provided to identify the species.An updated nomenclature along with important synonyms, habitat and distribution are provided under each taxon, while chromosome numbers have been cited whenever available.A medium-sized to large, perennial, suspended aquatic herb.Rhizoids present at the base or shortly above the base of the peduncle, bearing botryform or leaf-like branches.Stolons filiform, terete, branched, papillose.Leaves very numerous, semicircular in outline, 1-8 cm long, divided from the base into 3-5 semiverticillate primary segments, the secondary segments pinnate, alternate, each pinna dichotomously divided into numerous further segments, the ultimate segments capillary, terete, setulose.Traps dimorphic, obliquely ovoid.Racemes 5-25 cm long, up to 10-flowered.Bracts ovate to suborbicular, basifixed, 1-nerved, truncate at base, acute to acuminate at apex.Bracteoles absent.Flowers up to 10 mm long.Pedicels 6-20 mm long.Calyx lobes subequal, ovate to oblong, fleshy.Corolla bright yellow; upper lip ovate, hairy at base, obtuse to retuse at apex; lower lip obovate, hairy at throat, truncate, undulate at apex.Spur more or less equal to lower lip in length, papillose, glandular hairy at base, obtuse at apex.Stamens c. 2 mm long; filaments curved, dilated above, papillose; anther thecae confluent.Ovary subglobose.Style thick; stigma 2-lipped, lower lip hairy, margin ciliate, upper lip obsolete.Capsule globose with a long beak, circumscissile.Seeds polygonal, margin winged.Flowering and fruiting period: July to April with a peak during October to January.
Habitat: Common in ditches, beels, lakes, pools, ponds, swamps and in still or slowly flowing water and rice fields.
Distribution within Bangladesh : This species is distributed throughout the country.
Habitat: In wet and marshy areas near perennial water bodies, falls, streams, lakes and in rice fields.
Distribution within Bangladesh : It is commonly found in all the districts of the country.
Habitat: In wet or marshy sandy soil and mud.Distribution within Bangladesh : It is common throughout the country.Distribution outside Bangladesh : Africa, Australia, Malaysia, New Zealand, Northern Asia, including the USSR, China, Mongolia, Korea and Japan, and Tropical Asia from Pakistan to Indo-China.
Habitat: In shallow still or slowly running water, mud, ditches, pools, lakes, river backwaters, bogs, swamps and marshes.Also found in deep water but not flowering unless supported on floating mats or living or dead vegetation.
Habitat: Along wet and marshy places, twining among themselves or on other plants.Distribution within Bangladesh : This species has been recorded from North Bengal (Prain 1903) some parts of which fall under the territory of present Bangladesh.
Distribution outside Bangladesh : Africa, Malaysia, Northern Asia including the USSR, China, Mongolia, Korea and Japan, and tropical Asia from Pakistan to Indo-China.
Habitat: In still or slow running water, ponds, tanks, lakes and rice fields.Distribution within Bangladesh : It is found all over the country.Distribution outside Bangladesh : Afghanistan, Africa, Australia, Bhutan, Europe, India, Indo-China, Indonesia, Malaysia, Myanmar, Nepal, Pakistan and Sri Lanka.
Capsule wall of uniform thickness.Pedicel not longer than the calyx.bifida -Capsule wall thickened on either side of the line of dehiscence.Upper calyx lobe not or scarcely wider than the lower, broadly ovoid.scandens 4. Peduncle with a whorl of inflated organs above its middle.Inflatted organs sessile, with a leaf-like segments at the apex only.