THREE NEW SPECIES OF ARACEAE FROM BANGLADESH

Three new species belonging to two genera of Araceae from Bangladesh, namely Alocasia hararganjensis H. Ara & M.A. Hassan, Alocasia salarkhanii H. Ara & M.A. Hassan and Typhonium elatum H. Ara & M.A. Hassan are described and illustrated. Diagnostic morphological characters of each of the new species are provided. A comparative morphological characteristic for each new species with their closest described species has also been provided. Introduction The family Araceae de Juss. is represented globally by 3,645 species under 144 genera (Boyce and Croat, 2011). The family is represented in Bangladesh by 27 genera and 109 species, of which 80 species are wild and 29 are cultivated (Ara, 2016). During revisionary work of the family Araceae from Bangladesh the first author made an extensive field survey (137 field trips) throughout the country, especially in the hilly forest areas during 1988-2014 and collected 2,698 aroid specimens. Most of the collected specimens were identified by the first author. However, fifteen specimens remain distinct from any previously described and named species by different morphological characters. Twelve specimens identified belonging to the genus Alocasia (Schott) G. Don were not identical to any other described species. However, nine specimens of Alocasia (Schott) G. Don are closely related to Alocasia fallax Schott and remaining three are closely related to A. fornicata (Roxb.) Schott. Rest three specimens were identified as to belonged to the genus Typhonium Schott. These specimens are morphologically related to Typhonium trilobatum (L.) Schott. These specimens were critically examined and compared with the identified specimens of Alocasia (Schott) G. Don and Typhonium Schott available at BK, BKF, BM, CAL, DACB, K, DUSH (Dhaka University Salar Khan Herbarium), HCU (Herbarium of Chittagong University), BCSIRH (Herbarium, Bangladesh Council for Scientific and Industrial Research) and BFRIH (Herbarium, Bangladesh Forest Research Institute). Moreover, consultation of the relevent literatures (Wallich, 1829-1849; Roxburgh, 1832; Wight, 1843-1845; Hooker, 1893; Jackson, 1893-1955, Prain, 1903; Engler, 1920; Engler and Krause, 1920; Hu, 1968; Nicolson, 1976, 1979, 1987; Nasir, 1978; Nicolson and Sivadasan, 1981; Mayo, 1985; Karthikeyan et al., 1989; Hay, 1991, 1993, 1998, 1999; Noltie, 1994; Sriboonma et al. 1994; Sookchaloem, 1995; Mayo et al., 1997; Hetterscheid and Boyce, 2000; Toha, 2000; Boyce, 2007; Li et al., 2010) on the family Araceae revealed that collected specimens differed from other described species of the genus Alocasia (Schott) G. Don and Typhonium Corresponding author, Email: bnh_mirpur@yahoo.com Department of Botany, University of Dhaka, Dhaka-1000, Bangladesh.


Introduction
The family Araceae de Juss. is represented globally by 3,645 species under 144 genera (Boyce and Croat, 2011).The family is represented in Bangladesh by 27 genera and 109 species, of which 80 species are wild and 29 are cultivated (Ara, 2016).

Results and Discussion
The major morphological differences between the new species Alocasia hararganjensis H. Ara & M.A. Hassan and its closely allied species Alocasia fallax Schott are outlined in Table 1. ) Schott but can be easily differentiated by the colour of petiole and peduncle deep purple; shape of lamina long elliptic; number of inflorescences groups less than 4; length of style c. 0.5 mm long; male zone c. 2.3 cm long; and width of the appendix base and male zone are equal.
Small to moderately robust herb.Stem erect to decumbent, up to 4 cm in diameter, c. 60 cm long, clothed in the brown remains of old leaf bases.Leaves several together, held almost erect or slightly curved; petiole 35-52 cm long, sheathing c. 1/3 from the base of petiole, eglandular, deep purple, wings of the sheath out-rolled; blade hastato-sagittate, rather narrowly triangular, margin entire to slightly undulate, glossy, leathery, dark green, glabrous adaxially, pale green and pubescent abaxially, 31-51 cm long, 14.0-21.5 cm in diameter at the base; anterior lobes 18-33 cm long with apiculate tip 0.6-1.0cm long; anterior costa prominent on both surfaces, glabrous on both surfaces, primary veins 6 on each side, prominent on both surfaces, diverging at 45 0 -90 0 , secondary venation flush on both surfaces, mostly arising from the primary veins at a wide angle, then deflected towards the margin, forming variously well-defined interprimary collective veins or these absent, interprimary collective veins when present weakly undulating to strongly zig-zag at base broad acute angles; submarginal vein 0.8-1.0cm from the margin; glands in the axils of primary veins absent or extremely inconspicuous; posterior lobes 13-18 cm long, acute, peltate, 2.3-3.0 cm long; posterior costae straight to incurved.Inflorescences 3 in the center of the leaf crown, bloom one after another, subtended by a cataphyll, cataphyll up to 25 cm long, purple; peduncle deep purple, smooth, 26-31 cm long, 0.7-1.3cm in diameter at the base.Spathe c. 15 cm long; lower spathe convolute, c. 4.2 cm long, green; limb c. 11.7 cm long, c. 4.8 cm in diameter, light yellowish with violet or pink mixed on both sides.Spadix shorter than spathe, c. 11.5 cm long.Lower fertile female zone c. 1 cm long; sterile female zone c. 0.5 cm long, c. 1.3 cm in diameter at the base; pistil closely packed; ovary sub-globose, green, c. 2 x 2 mm, unilocular, with basal placenta; style distirct, stout, c. 0.5 mm long, c 0.8 mm in diameter, light yellow; stigma 3-4 lobed, lobes acute, light yellow; sterile interstice c. 2 cm long, narrower than the fertile zones,  corresponding with the spathe constriction; lower synandrodia often with incompletely connate staminodes, the rest elongate rhombo-hexagonal, flat-topped; male zone cyclindric, somewhat tapered at the base, c. 2.3 cm long, c. 0.8 cm thick, ivory in colour; synandria more or less hexagonal, c. 2 mm in diameter, androus; appendix c. 3.5 cm long, c. 0.8 cm thick at the middle, about the same thickness at the male zone, gradually tapering to a pointed tip, cream coloured.Fruit orange-red; fruiting peduncle 33-35 cm long, fruiting spathe ovoid, 4-6 cm long.
Flowering and fruiting period: May -August.
Ecology: Grows on the hilly area as undergrowth.Etymology: The species is named in honour of Dr. Md.Salar Khan, known as the father of plant taxonomy in Bangladesh.
The major morphological and cytological differences between the new species Alocasia salarkhanii H. Ara & M.A. Hassan and its closely allied species Alocasia fornicata (Roxb.)Schott are outlined in Table 2. Conservation status: Critically Endangered (IUCN, 2017).Located in a very restricted area, should be conserved both by in situ and ex situ methods.c. 3.5 cm long, outside pale green, inside glossy dark purple; blade c. 36.5 cm long, outside pale green, inside glossy dark purple.Spadix shorter than spathe, c. 29 cm long.Female zone c. 0.8 cm long, c. 0.8 cm in diameter, flowers congested; sterile zone between female and male zone, 2.7-4.0 cm long, the lower 0.5-2.2cm with yellow staminodes, the remainder naked, light pink, longitudinally grooved; male zone cylindrical, c. 1.8 cm long, c. 1 cm in diameter, base and top oblique, flowers congested; appendix very shortly stipitate, narrowly lanceolate, 20-24 cm long, c. 1 cm in diameter at the base, top acute, base multifurcate, with surface shallowly and irregularly furrowed, dark purple, producing a strong unpleasant smell at female anthesis.Stamens 0.6-0.9mm long, light pinkish.Staminodes filiform, c. 1.6 cm long, c. 0.5 mm in diameter, dark yellowish, curled.Ovary elongate, cylindric, c. 1.5 mm long, 1.1-1.2mm in diameter, white with a faint pinkish flush near the top, unilocular, with one basal ovule; stigma sessile, depressed, hemispheric, c. 0.8 mm in diameter, c. 0.2 mm high, papillose, pink.Fruit not observed, usually die before fruit formation.
Ecology: Grows on the hilly area as undergrowth.
Distribution: Central parts of Bangladesh (Sherpur district).Etymology: The species is named after tallness of its habit.
The major morphological and cytological differences between the new species Typhonium elatum H. Ara & M.A. Hassan and its closely allied species Typhonium trilobatum (L.) Schott are presented in Table 3.
Conservation status: Endangered (IUCN, 2017).Collected from a single locality, now conserved through ex situ in a home garden.
Typhonium elatum H. Ara & M.A. Hassan differs from its closely related species T. trilobatum (L.) Schott by its green colour petiole which is more than 50 cm long; peduncle colour light green; length of the spathe c. 40 cm long and shape narrowly lanceolate; spadix length c. 29 cm long; base of the appendix multifurcate and colour of the staminode yellow.
Alocasia hararganjensis H. Ara & M.A. Hassan is closely related to A. fallax Schott but readily differentiated by the leaf shape which are narrowly to ovate sagittate with acute tip; tip of the cataphylls c. 8 cm long; and no sterile male zone above the sterile interstice.