72 DIFFERENTIATION AND SPECIFICITY OF STARCHES. 



A. Simple spherical grains. Continued. 



(b) Not more than lOfj. in diameter: Calamus, Eunonymus, Gelsemium, Granatum, Quillaja, 



Sangiiinaria, Serpentaria, Tonka, Ulmus, Xanthoxyluin. 



(c) Not more than 15n in diameter: Apocynum, Cinchona, Colchici semen (in caruncle only), 



Convallaria, Sumbul, Valeriana, 

 (rf) Not more than 20n in diameter: Glycyrrhyza, Phytolacca, 

 (e) Not more than SOjx in diameter: Rumex, Stillingia. 



B. Compound spherical or polygonal grains. 



(a) 2 to 3 compound: Belladona radix (5 to 15/i), Sassafras (7 to 20/z), Veratrum viride (7 

 to 20m). 



(6) 2 to 4 compound: Aconitum (4 to 12/i), Cinnamonum (7 to 15^), Colchici cormus (7 to 

 20^), Ipecacuanha (4 to IAjjl, those of Carthagena ipecac being uniformly larger), 

 Kramcria (20 to 30/i), Rheum (5 to 20ja), Sarsaparilla (7 to 20/i). 



(c) 2 to 6 compound: Podophyllum (5 to 12/i). 



(d) More than 6 compound: Capsicum (3 to 7|t), Cardamonum (1 to 4^1), Cubeba (1 to 4/j), 



Gossypii cortex (5 to 20ai), Mezereum (10 to 15/u), Myristica (5 to ly), Pimenta (7 to 

 10m), Rubus (3 to 7m). 



C. Ellipsoidal or ovoid grains. 



Althisa (10 to 20m), Geranium (10 to 15m), Glycyrrhiza (5 to 10m), Pareira (7 to 15m), Physo- 

 stigma (25 to 40m), Rumex (10 to 20m), Stillingia (15 to 30m), Strophanthus (2 to 4m), 

 Zingiber (15 to 30m). 



D. Grains of characteristic shape. 



Calumba (25 to 35m), Iris florentina (15 to 30m), and potato and other starches, such as arrow- 

 root, wheat, corn, yam, canna, bean, pea, cassava. 



E. Altered grains. Guarana (10m), Jalapa (15 to 35m; also 2 to 3 compound grains), Tragacantha 



(2 to 10m), turmeric in masses (70 to 140m). 



F. Amylodcxtrin grains. Mace contains starch-grains which give a rcddisli color with iodine. 



Kraemer notes tliat leaves, herbs, and flowers do not as, a rule, contain starch. 



Winton's Classification op Starches.* 



Winton records that the forms of the grains are so numerous, even in the same variety, 

 as to forbid accurate classification, but that the following are the more striking. : 



1. Globular. The starch of the peanut and some grains of maize. 



2. Lenticular. The large grains of wheat, rye, and barley. 



3. Ellipsoidal. The starch of legumes. 



4. Ovoid or pear-shaped. The starch of potato, canna, Bermuda arrowroot, yam, and banana. 



5. Truncated. Most of the grains of cassava, batata, and sago. 



6. Polygonal. The starch of maize, rice, oats, and buckwheat. 



Winton also gives an analytical key by Moellar to commercial starches that is based 

 upon general histological characteristics. 



Many other classifications might be quoted, without, however, any material advantage. 



PROPERTIES OF THE STARCH-GRAIN IN RELATION TO MENDELISM. 



Gregory (The New Phytologist, 1903, ii, 226) found that the starches of round and 

 wrinkled peas occur in two very different types. (See Plates 8, 9, and 10, figs. 47 to 56.) 

 In the round seeds the jjeripheral cell-layers of the cotyledons contained a few oval starch- 

 grains which did not e.xceed 0.06 mm. in the greatest diameter. In the third layer the 

 grains reached 0.2 mm. in length, while the more deeply situated cells were crowded with 

 oval grains measuring as much as 0.34 mm. in the greatest dimension. The grains were 

 regular in shape, with a definite center surrounded by well-marked lines of stratification. 

 In the ivrinkled peas the grains of the jieripheral layers were of about the same size as those 

 of the round peas, but were of a different type, occurring in irregular spheres with several 



* The Microscopy of Vegetable Foods, New York, 1906, 645. 



