140 



PLANT ORGANS OR PARTS OF PLANTS. 



The color of the powder is whitish ; with age it becomes 

 grayish to brownish white. The taste is acrid. The 

 powder, under the microscope, shows the following gen- 

 eral elements: Starch, ducts, and parenchyma; the starch 

 predominating. 



The starch is abundant; the grains are large and 

 characteristic. They are mainly compound, in groups of 



Fig. 23- — Powdered Colchicum. 



S, Starch grains, simple and compound; P, Pr, parenchyma; AV, SV, 



annular and spiral vessels; Ph, tissues from the phloem. 



two, three, or four, with central hilums, which are triangu- 

 larly or quadrangularly lacerate, or sometimes distinctly 

 many -rayed. The concentric markings are not promi- 

 nent. The polariscopic cross is usually rectangular, 

 swollen in the middle, and attenuate at the periphery. 

 The grains range from 5 to 22 microns in diameter. 



The ducts are not numerous; they are usually spiral 

 or annular, sometimes pitted. 



