68 DIFFERENTIATION AND SPECIFICITY OF STARCHES. 



Polytone starch-grains, which arc distinguished especially liy the periodic inequality of their 

 lamellae, are found most abundantly and constantly in storage organs which live for 

 several years, in consequence of which the carbohydrate passes through several 

 periods of storage and disaj)pearance. They may be found in the rhizome tips of 

 Adoxa in the spring of their second calendar year, and in 3-year-old bulbs of Hya- 

 cinthus. These grains are also most readily formed in perennial plants, as observations 

 in PeUionia have shown. 



(c) Solitary starch-grains. Grains which grow singly in one chromatophore. 



(d) Adelphous starch-grains. Those which grow along with other grains in one chromato- 



phore. They may be di- to poly-adelphous; up to 6-adeli)hous would be designated as 

 oligo-adelphous. 



(e) Monotone starch-grains. Grains which during their entire life have imdcrgone periods 



of solution, leaving coherent traces of each of the lamellae formed during the period 

 of storage. Perfect monotone starch-grains in which there still exists a trace of every 

 lamella which has been formed and in which, even if eccentric, the lamellae are closed 

 are exceedingly rare. This term is also to be used in all cases in which no distinct 

 characters of a polytone type are present. 



(f) Polytone starch-grains. Grains that have during their development undergone two or 



more periods of solution in which numerous lamellae completely disappear or de- 

 crease in nidth, interspersed with other periods during which they developed as the 

 relative monotone type. Polytone grains if they have an eccentric structure show a 

 series of lamellae which are open laterally. 



The similarity of the monotone starch-grains at one period in the same plant part 

 and of the various individuals of a definite plant part is a recognized phenomenon. This 

 is the consequence of the specific nature of the chromatophore and cytoplasm and of the 

 approximately similar biology of the latter. Monotone starch-grains which grow at 

 different periods in one cell of a plant may, however, assume very divergent forms, since 

 in the course of the life of the cell changes occur in the size, consistency, and chemistry 

 of the chromatophores and cytoplasm. Thus, in the chromatophores of one cell of the scale 

 leaves of Adoxa moschatellina of the first year's growth oialy monarch eccentric, conical 

 starch-grains are found, while in the same cells of the second year usually only polyarch, 

 almost centric, starch-grains are observed. The small variations in the form of the 

 starch-grains found in the same plant part are not due alone to the fact that they were 

 not formed at the same time, but also because every cell has its own biology, even every 

 chromatophore has its individual properties. In different organs of the same plant grains 

 may assume a great variety of form. Thus, the leucoplast of the tubers of Solanwm 

 tuberosum form, besides complex and oligo-adelphous grains, mostly solitary, monarch, 

 eccentric, conical, or oval grains, with a length of 200^/, and which have definite, rather 

 delicate, irregular lamella. In the chloroplasts of the potato, large, solitary, inverted 

 conical-shaped starch-grains occur which have at regular intervals refractive lamellae of 

 equal width. 



The polytone starch-grains of one plant part, even in one plant cell, are in general 

 less similar than the monotone grains, since in them the distinctions which originally 

 existed are intensified through the variations caused by the marked solution alterations of 

 the monotone grain. 



A. Monarch Starch-Grains. 

 (a) Solitary starch-grains. 



I. Centric starch-grains. Hilum in the mathematical center; lamellae always equal at two 

 diametrically opposite points (Nageli, Tyjje 1). Such centric grains, as already 

 noted by Nageli (see Types 1, 2, and 3), occur only in seeds. It is therefore evi- 

 dent that, just as in the seeds the cytoplasm is abundant and dilute, the chro- 

 matophores lack density and have a tendency to expansion. 



