760 STARCHES OF IRIDACE^. 



Differentiaiion of Certain Starches of the Genus Sparaxis. — Continued. 



Effects of Various Reagents. 

 Reaction with Chloral Hydrate-Iodine. 



S. grandiflora alba: Begins immediately; complete in 

 practically all in 2 minutes and in all in 8 minutes. 



S. var. (Alberline): Begins immediately| complete in 

 practically all in a minute and in all m 3J^ minutes. 



Reaction with Chromic Acid. 



S. grandiflora alba: Begins immediately; complete in 

 practically all in 2 minutes and in all in 63^ 

 minutes. 



S. var. (Albertijie): Begins immediately; complete in 

 practically all in a minute and in sJl in 1 ^ minutes. 



Reaction tnth Pyrogallic Acid. 



S. grandiflora alba: Begins immediately: complete in 

 practically all in 30 seconds and in all in 60 seconds. 



Effects of Vabious Reagents. — Continued. 



Reaction with Pyrogallic Acid. — Continued. 



S. var. {Alberline): Begins immediately; complete in 

 practically all in 25 seconds and in all in 45 seconds. 



Reaction with Ferric Chloride. 



S. grandiflora alba: Begins immediately; complete in 

 practically all in 4 minutes and in all in 12 minutes. 



S. var. (Alberline): Begins immediately; complete in 

 practically all in 3 minutes and in all in 10 minutes. 



Reaction with Purdy's Solution. 



S. grandiflora alba: Begins immediately; complete in 

 practically all in 2 minutes, but not complete even 

 at the end of 30 minutes. 



S. var. (Alberline): Begins immediately; complete in 

 practically all in a minute and in all in 10 minutes. 



practically 



NOTES ON THE STARCHES OF SPARAXIS. 



These starches differ unessentially in histological features, and the same is true in regard to 

 their reactions. Comparing S. grandiflora alba with S. var. (Albertine), it will be foimd that the 

 former exhibits a lower degree of polarization, lower reactivity with iodine and the anilines, lower 

 temperature of gelatinization, and lower sensitivity throughout with the chemical reagents. The 

 differences are, however, usually not marked, and the starches are probably from closely related plants. 



GENUS IXIA. 



Ixias are bulbous plants, native of the Cape of Good Hope and largely cultivated, in the form 

 chiefly of hundreds of horticultural varieties. About 23 species are known. The ixias hybridize so 

 freely that not only are the varieties numerous, but continually being added to; and they are so 

 mixed by interbreeding that reference of horticultural varieties to the exact parent-species is sel- 

 dom possible. The starches from two species and one garden variety of unknown parentage were 

 studied: /. speciosa Andr. (7. craterioides Ker.), I. viridiflora Lam., and I. var. (Emma). 



STARCH OF IXIA SPECIOSA. (Plate 77, figs. 459 and 460. Chart 298.) 



Histological Characteristics. — In form the grains are simple, and are isolated with the exception 

 of many aggregates, in the form of doublets and triplets of equal or unequal sized components. 

 Practically all the isolated grains have one or more, usually two or three, pressure facets at their 

 distal ends. The surface of the grains tends to be rounded and quite regular. The conspicuous 

 forms are the hemispherical with usually one to three facets at the base or distal end, spherical, 

 and spherical to oval and elliptical; there are also a number of polygonal grains. Among the small 

 grains are many spherical grains and others ranging from this form to rod-like, and also polygonal. 

 The grains are not flattened and are of the same thickness as width, and hence spherical when 

 seen on end. 



The hilum is a comparatively large, round, distinct spot, usually slightly eccentric and commonly 

 in the median line. It is rarely fissured, and the fissure is a short, narrow, straight, transverse 

 line. The doublets and triplets often have Unes or fissures at the places of union of the component 

 grains, and two or more hila may be observed on a single grain. 



The lamdlce are fairly distinct, rather coarse, regular, continuous rings, usually of the same form 

 as the margin of the grain when distal from the hilum. There are about 4 to 6 on the larger grains. 



The grains vary in size; the smaller are 2/z, the larger hemispherical type 18 by 15^ in length 

 and breadth. The common size of the larger grains is 12 by lOyu in length and breadth. 



Polariscopic Properties. — The figure is usually somewhat eccentric, fairly distinct, and generally 

 clear-cut. Sometimes one or more of its lines are broader than the others and not quite clearly 

 defined. The center of the figure is sometimes a rather large, dark area. Two or more fissures may 

 be seen on the doublets and triplets, and the figure may be modified by the facets. 



