THREE NEW SPECIES OF CURCUMA L . ( ZINGIBERACEAE ) FROM BANGLADESH

Three new species of the Section Masantha Horan. of the genus Curcuma L. (Zingiberaceae), viz., C. roxburghii Rahman et Yusuf, C. wallichii Rahman et Yusuf and C. wilcockii Rahman et Yusuf from Bangladesh are described and illustrated. These species were collected from the forests of Rangamati, Moulvi Bazar, Sylhet and Tangail districts. Diagnostic morphological characters from closely related taxa are discussed. A key to the Bangladesh species of Section Masantha Horan. is presented. Introduction In course of the study on the Zingiberaceae for its complete inventory for the Flora of Bangladesh we have made an extensive survey throughout the country and collected a number of specimens of the family during the period from 1993 to 2000. During our field trips we have recognized the occurrence of two distinct groups of Curcuma L. in the wild; one group with the spikes lateral to the leafy shoots belonging to Section Exantha Horan. and the other group with the spikes terminal on the leafy shoots belonging to Section Masantha Horan. Survey of the relevant literature of Roxburgh (1814, 1820, 1832), Wallich (1829-49), Baker (1890), Prain (1903), Heinig (1925), Kanjilal et. al. (1934), Raizada (1941), Sinclair (1956), Rahman (1995), Rahman and Yusuf (1996, 1997) showed that, the genus Curcuma is represented in the flora of Bangladesh by nine species of which two species, C. amada Roxb. and C. longa L. belong to the Section Masantha Horan. On the other hand, remaining seven species belong to the Section Exantha Horan., and these are C. amarissima Rosc., C. aromatic Salisb., C. caesia Roxb., C. ferruginea Roxb., C. latifolia Rosc., C. rubescens Roxb., and C. zedoaria (Christm.) Rosc. During field trips we came across some characteristically distinct flowering populations of Curcuma with terminal spikes growing in the forest floors of Rangamati (one of the Chittagong Hill Tract districts), Lawachara rain forest (Moulvi Bazar district), forest of Tamabil hills (Sylhet district) and Madhupur Sal forest (Tangail district) which hitherto represent undescribed species of the Section Masantha Horan. The flowering specimens were collected and preserved for identification. The rhizomes were also collected and grown in the field of Bangladesh Council of Scientific and Industrial Research (BCSIR), Chittagong and in the Botanic Garden of Chittagong University. The specimens were critically examined and compared with the identified specimens of Curcuma L. available at CAL, BM, DACB, E, K, BCSIRH, DUSH (Dhaka University Salar Khan Herbarium) and HCU (Herbarium of Chittagong University) and finally confirmed them as three new species in Section Masantha Horan. of the genus Curcuma L. These new species are similar to C. amada Roxb. and C. longa L. belonging to the same Section but characteristically different from each other for a number of variations in floral structures, leaf morphology and in shape and colour of rhizomes. Corresponding author. Email: atiquerahman125@hotmail.com Bangladesh Council of Scientific and Industrial Research, Chittagong, Bangladesh.


Introduction
In course of the study on the Zingiberaceae for its complete inventory for the Flora of Bangladesh we have made an extensive survey throughout the country and collected a number of specimens of the family during the period from 1993 to 2000.During our field trips we have recognized the occurrence of two distinct groups of Curcuma L. in the wild; one group with the spikes lateral to the leafy shoots belonging to Section Exantha Horan.and the other group with the spikes terminal on the leafy shoots belonging to Section Masantha Horan.Survey of the relevant literature of Roxburgh (1814Roxburgh ( , 1820Roxburgh ( , 1832)), Wallich (1829-49), Baker (1890), Prain (1903), Heinig (1925), Kanjilal et. al. (1934), Raizada (1941), Sinclair (1956), Rahman (1995), Rahman andYusuf (1996, 1997) showed that, the genus Curcuma is represented in the flora of Bangladesh by nine species of which two species, C. amada Roxb.and C. longa L. belong to the Section Masantha Horan.On the other hand, remaining seven species belong to the Section Exantha Horan., and these are C. amarissima Rosc., C. aromatic Salisb., C. caesia Roxb., C. ferruginea Roxb., C. latifolia Rosc., C. rubescens Roxb., and C. zedoaria (Christm.)Rosc.
During field trips we came across some characteristically distinct flowering populations of Curcuma with terminal spikes growing in the forest floors of Rangamati (one of the Chittagong Hill Tract districts), Lawachara rain forest (Moulvi Bazar district), forest of Tamabil hills (Sylhet district) and Madhupur Sal forest (Tangail district) which hitherto represent undescribed species of the Section Masantha Horan.The flowering specimens were collected and preserved for identification.The rhizomes were also collected and grown in the field of Bangladesh Council of Scientific and Industrial Research (BCSIR), Chittagong and in the Botanic Garden of Chittagong University.The specimens were critically examined and compared with the identified specimens of Curcuma L. available at CAL, BM, DACB, E, K, BCSIRH, DUSH (Dhaka University Salar Khan Herbarium) and HCU (Herbarium of Chittagong University) and finally confirmed them as three new species in Section Masantha Horan. of the genus Curcuma L. These new species are similar to C. amada Roxb.and C. longa L. belonging to the same Section but characteristically different from each other for a number of variations in floral structures, leaf morphology and in shape and colour of rhizomes.
Curcuma wilcockii Rahman et Yusuf is distinct from other species of the Section for its orange-yellow flowers, anthers without spur and indistinct colour of coma and fertile bracts.C. roxburghii Rahman et Yusuf is distinct for its exserted flowers and turmeric smell of rhizomes.C. wallichii Rahman et Yusuf, on the other hand, is distinct for its non-exserted flowers, purplish pink coma bracts and hairy ovary.Hence, the Section Masantha Horan.recognized here to be representing in the flora of Bangladesh by five species including these three new species.A key to these five taxa are presented.The new species are described with Latin diagnosis.Illustrations with photographs of habits are provided.

Key to the species:
1.
Ecology: Grows on the hill slopes in partial shade, at about 570 m altitude.
Conservation status: It is known from the type locality only.Few populations were seen at the type locality.It can be graded as LR (cd) category (IUCN, 1994).
Etymology: This species is named in honour of Dr. William Roxburgh, father of Indian Botany, who has made outstanding contribution in collecting and naming most of the plants of the then Bengal.

Curcuma wallichii
Ecology: Grows in the rain forest area in partial shades.Conservation status: It is known from the type locality only.A few populations were seen at the type locality.It can be graded as LR (cd) category (IUCN, 1994).
Etymology: It is named in honour of Dr. Nathaniel Willich, superintendent of the then East Indian Company's Museum, Calcutta, who has collected and named a huge number of plants from the Indian subcontinent including the area now in Bangladesh.
-Flowers not exserted, more or less equal to the bracts.43.Base sheaths green; lamina puberulous on the upper side; coma bracts pinkish or whitish; fertile bracts pale green; rhizomes pale yellow with smell of green mango; ovary villous throughout.C. amada-Base sheaths purple; lamina glabrous on both sides; coma bracts light purple, white at base; fertile bracts light green with purple edges; rhizomes yellow with light smell of turmeric; ovary hairy at the top only.C. roxburghii4.Coma bracts greenish or white with purplish tips; fertile bracts light green; staminodes up to 12 mm long, ligulate, creamy white; labellum oblong, 15 mm long; ovary hairy at the top.C.longa-Coma bracts purplish pink; fertile bracts light green, pinkish on the apical border; staminodes 16 mm long, oblong, light yellow; labellum obovate, 20 mm long; ovary hairy throughout.C.