VEGETABLE CYTOLOGY 



79 



CHARACTERISTCS or IMPORTANT COMMERCIAL STARCHES 



Potato Starch (Solanum tuberosum) 



Mostly simple, conchoidal or ellip- 

 soidal, with occasional spheroidal 

 and two- to three-compound grains. 



Size: 5 to 12 5 n 



Hilum: circular, at smaller end of 

 grain. 



Lamellae: concentric and eccentric. 



Polarization cross very distinct ; beau- 

 tiful play of colors with selenite 

 plate. 



Maranta Starch (Maranta 

 arundinacea) 



Ellipsoidal to ovoid. 



Simple. 



Size: 10 to 65 /*. 



Hilum: a transverse or crescent- 

 shaped cleft in center or near 

 broad end of grain. 



Lamellae : usually indistinct. 



Polarization cross very distinct; fine 

 play of colors with selenite plate. 



X Corn Starch (Zea Mays} 



Polygonal to rounded. 



10 to 35/z. Most grains over i^/j. 

 in diameter. 



Simple. 



Hilum: circular or a two- to five- 

 rayed cleft. 



Lamellae: indistinct. 



Polarization cross distinct but no 

 marked play of color with selenite 

 plate. 



Rice Starch (Oryza saliva) 



Polygonal.. 

 2 to io/i in diameter. 

 Simple or two- to many-compound. 

 Hilum: usually indistinct, occasion- 

 ally a central cleft. 

 Lamella) : indistinct. 







Polarization cross distinct but no 

 play of colors with selenite plate. 



Wheat Starch (Triticum satwum} 

 Circular grains appearing lenticular 



shaped on edge view; simple. 

 Large grains 28 to 45^1 in diameter. 

 Hilum: central, appearing as dot, 



but usually indistinct. 

 Lamellae : generally indistinct, when 



present concentric. 

 Polarization cross indistinct; no 



play of colors with selenite plate. 



Rye Starch (Secale cereale) 

 Grains having a similar shape to 



those of wheat starch but many 



larger; simple. 



Large grains 20 to 52^' in diameter. 

 Hilum: a star-shaped central cleft or 



indistinct in some grains. 

 Lamellae : concentric. 

 Polarization cross distinct. 



Barley Starch (Hordeum distichon] 



Grains having a similar shape to 

 those of wheat starch but fre- 

 quently tending to bulge on one 

 side and so appear sub-reniform; 

 large grains smaller; simple. 

 Grains appear elliptical to lemon 

 shaped in edge view. Large 

 grains usually 18 to 25^, occa- 

 sionally up to 30/4 in length. 



Hilum: centric or circular or cleft, 

 often indistinct. 



Lamellae : concentric, often indistinct. 



Polarization cross distinct. 



Buckwheat Starch (Fagopyrum 



esculentum) 



Grains simple and compound. 

 Simple grains polygonal or rounded 



polygonal. 



