14 STAECHES. 



(9) Curcuma Starch. 



Curcuma starch (Fig. 9) is obtained from the rhizomes of Curcuma 

 angustifolia, Roxb., C. leucorrhiza, Roxb., and other species of 

 Curcuma. It is more commonly known in commerce as East 

 Indian arrowroot. 



The grains of which this starch is composed are oval, elliptical, 

 almost rectangular or rounded in outline. At one of their extremi- 

 ties they usually terminate in a short obtuse point in which the 

 very eccentric punctiform hilum is situated, surrounded by con- 

 centric striae. The grains are so thin that when viewed on their 

 edges they appear extremely narrow ; several may often be seen in 

 this position adhering together by their flat sides. Mixed with these 

 larger grains are smaller ones of similar shape. 



Curcuma starch grains average from 3(V to 60//, in length, 25jU 

 to 35/i in breadth, and Ifj. to 8/j. in thickness. The length of the 

 smallest grains scarcely exceeds 15/x. to 25/x, but the largest 

 grains from C. leucorrhiza may attain as much as 140/x. 



(10) Tous les Mois Starch. 



This starch (Fig. 10), which is also known as Queensland arrow- 

 root, is obtained from the rhizomes of Canna edulis, Linn., and 

 other species of Canna. The grains of which it consists are so 

 large as to impart a satiny- white appearance to the starch. The 

 majority are seldom less than 60/x or 70^ in length, whilst the 

 largest occasionally reach 110/t to 130/A. They are usually simple 

 and are elliptical, slightly oval, conchoidal, or sometimes reniform 

 in outline ; they are flattened and often prolonged at the narrower 

 end to a short obtuse point in which the rounded hilum is situated, 

 surrounded by concentric striae. 



