252 DIPFEIIENTIATION AND SPECIFICITY OF STARCHES, 



iit tlio toji of tliese bulbs. Complex compound grains and separated-grains of the same do 

 not occur; thej' are either not formed at all or they fall to pieces and the sei)arated-grains 

 then look like the simple ones. Fissures usually radiating from the hilum are formed in 

 grains in bulbs which have been allowed to dry over the winter, and the divisions between the 

 components become wider. The grains in the outer, decayed scales of the bulbs are under- 

 going disintegration, which usually begins where the partitions between the components 

 touch or nearly touch the surface. 



Canna lanuginosa Rose; Canna lagunensis Lindl., etc. (CannacecB.) Fresh root-stock. — Grains 

 simple, usually more or less mussel-shell-shaped; hilum very eccentric, lying in the upper, 

 narrow, protruding end. In this species as well as in others the hilum is frequently split 

 in two; 2, rarelj' 3 or 4, liila lying next to each other. In the longitudinal axis of the grains of 

 some species a single and here and there a double row of inclosed components is formed. 

 In the symmetrical grains this row is usually in the median line, while in the unsym- 

 metrical ones, the grains being usually more or less curved, it is found toward the con- 

 cave border. The number of inclosed grains varies from 2 to 12; either by transverse or 

 longitudinal fission of these grains individual ones arise, in which lamellae become visible 

 as they increase in size. 



Ficaria ranunculoides Moench.; Ranunculus ficaria Linn. {Ranunculaceas.) Dry thickened roots. — 

 Grains rounded-cuneiform, roimded-triangular, frequently unequally quadrangular, some- 

 times pentagonal, frequently somewhat irregular; about twice as broad as long; compi-essed 

 to half their wdth; in the triangular grains one of the rounded angles and in the quadrangular 

 ones the narrow side is thickened; the latter with a row of 2 to 6 or more hila at right angles 

 to the longitudinal axis; eccentricity one-fourth and one-sixth; the distal margin broad, 

 with a thinned knife-like edge, which terminates mostly on either side in rounded or some- 

 what pointed angles; lamellse none or indistinct; instead of the hila, small cavities, fre- 

 quently with single delicate, short, radiating fissures are found; dehcate separating fissures 

 between the components are rare. Size about 35/1. Among the above some doublets and 

 triplets and simple eccentric-cuneiform grains are observed. 



Cereus variabilis PfeifT. (Cactaceoe.) Fresh pith of the ste/«. ^Grains rounded or oval, usual!}' of 

 irregular form and with lamellae; with 2 to 6 and 9 larger or smaller inclosed components, 

 the latter when larger have lamellae, and are usually divided from one another by parti- 

 tions; lamellse eccentric; occasionally some of the larger components are also semi-compound. 

 Size about 80|U. Among these are simple grains of uncertain structure. 



Type 12. Grains Compound, with Fused Components. 



The components are not surrounded by a common substance, nor separated from one another 

 by lines of cleavage. At fii'st glance the gi'ains of this type bear a resemblance to certain semi- 

 compound grains, but differ from them in not possessing a common surrounding substance. They 

 also differ from the ordinary compound grains in the lack of lines of cleavage between the com- 

 ponents; and for this reason they do not, as a rule, split into separated-grains. In Commelina and 

 other species, compound grains arise by grains which were originally separate, and pressing upon 

 one another as the result of further growth, so that at first grains in one cell of the same generation, 

 and later those of older ones, fuse with one another, and at the same time the clefts between them 

 disappear. The whole cell lumen is then filled with a uniform, reticulated, parenchjTnatous mass, 

 in which the hollow space represents the soft, internal matter of the components, while the net- 

 like framework corresponds to the coalesced dense external substance. 



Commelina ccelestis Willd. {Commelinacece.) — Compound grains polyhedral, due to pressure; 1 to 2.5 

 times as long as thick, of parenchymatous structure consisting of 2 to more th an 200 com- 

 ponents, the latter usually fused with one another, rarely separated by delicate clefts, each 

 with a large angular cavity. Separated-grains (which occasionally can be set free by j^ress- 

 ing) rounded-angular or polyhedral. Size of the compound grains about 40 to 55yu, thick- 

 ness about 30yu. Size of the components 1.5 to 6 and 8,u. Some isolatetl simijle spherical 

 grains. Size about 9/u. In semi-ripe seeds the compound grains are sj^herical to oblong 

 (about 44m), consisting of apparently solid, equally dense components separatetl by delicate 

 lines or distinct, narrow clefts. In young seeds, where the endosperm has just begim to 



