Turmeric: The genus Curcuma (Medicinal & aromatic plants- Industrial profile) edited by P. N. Ravindran, K. Nirmal Babu, K. Sivaraman (2007- Curcuma longa, & other related species like Curcuma amada, Curcuma angustifolia, Curcuma aromatica, Curcuma ceesia, Curcuma zedoaria)
Curcuma L. is one of the charming genus in the family Zingiberaceae, we can easily distinguish the genus from other genera by means of inflorescence, a spike with prominent spiral bracts each subtending a cincinnus of flowers. In fact, it is very difficult to identify the species among the genus. Taxonomical history of the genus revealed that, the pioneer taxonomists (Roxburgh, 1820; Horaninow, 1862; Baker, 1890; Schumann, 1904) were proposed various sections depending on the position of spikes and absence or presence of anther spur. Recently Sabu (2006) revised the family Zingiberaceae in South India along with Costaceae.
Depending upon his studies, the major characters used for the identification of Curcuma’s are presence of anther spur, size of the pseudostem, presence or absence of root-tubers, rhizome colour and smell, colour of the coma bracts and proportion of flower with bract (flowers exceeding bract or not).
For example, we can easily identify C. aurantica (Syn. C. ecalcarata) from other species my means of the absence of anther spur. Likewise, in C. pseudomontana sessile tubers are absent and in C. vamana and C. oligantha coma bracts are absent. With regard to rhizome colour, rhizome blue within in C. aeruginosa, yellow to deep yellow within in C. zanthorrhiza, deep orange-yellow within C. longa and greyish yellow within C. aromatica. Regard to smell, C. amada rhizome with the smell of green mango. In many species, Curcuma possess lateral and central inflorescence like C. inodora.
As per efi thread :
We can easily differenciate this three species without flower by rhizome character and hairy nature.
C. aeruginosa : After its maturity the rhizome shows bluish or violet rings
C. xanthorrhiza : Rhizome colour yellow.
C. caesia : Of course the rhizome shows the bluish olour. But we can identify this species by the hairy nature. In this species the hairs are present in the upper part of leaf. This is the only one Curcuma sp. showing this character.
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