GENUS KANUNCULU8. 



867 



STARCHES OF RANUNCULACE/E. 



Class, Dicotyledones. Order, Ranales. Family, Ranunculaceae. Genera 

 represented: Ranunculus and Adonis. 



The Ranunculacea include 4 genera and over 200 species which are widely distributed and abun- 

 dant throughout the world in temperate and cold regions, and a few in mountainous parts of the 

 tropics. The family is typified by Ranunculus. 



GENUS RANUNCULUS. 



Ranunculus includes at least 200 species, nearly half of which are found native or naturalized 

 in North America, 15 species are found in Great Britain, and the others are widely distributed in 

 Europe, Asia, and Africa. Starches from two species were studied: R. hulbosus Linn. (R. spedosus 

 Hort.), a native of Eastern Europe and Africa, and naturalized in America and popularly known as 

 the buttercup or crowfoot, and by other similar names; and R. ficaria Linn., known in England as 

 the lesser celandine or pilewort or figwort, or Wordsworth flower, and which is native of Europe 

 and Asia. Many species have when fresh a very acrid juice, but the acridity disappears upon dry- 

 ing or boiling, and after such preparation they are used as a food by man and cattle. 



STARCH OF RANUNCULUS BULBOSUS. (Plate 97, figs. 577 and 578. Chart 381.) 



Histological Characteristics. — In form the grains are usually simple. There are a few compound 

 grains, many aggregates, and some clumps. Some grains have pressure facets. The outlines of 

 most grains are somewhat irregular, the conspicuous forms being the ovoid, oval, pyriform, elliptical, 

 round, dome-shaped to hemispherical ; also various indeterminate forms. The faceted grains do not 

 show the sharpness of angle of the facets so commonly seen in the faceted grains of starches of 

 other genera. Almost all show rounded irregularities, so that en masse they often resemble a cluster 

 of pebbles. Most of them show a depression extending transversely across the grain, and some of 

 the elliptical grains with a flattened base have a small hole or depression in the center of this part. 

 Some grains appear to be disks and some concave disks. 



The hiliini is a comparatively large, quite distinct, 

 round, non-refractive spot, situated eccentrically com- 

 monly about one-fifth of the longitudinal axis of the 

 grain, even in the round grains. It is rarely fissured, 

 and the fissure is narrow, short, and inconspicuous. The 

 hilum is sometimes elUptical or lenticular. There were 

 no double or multiple hila in the specimen examined. 



No lamellae are visible. 



The grains vary in size from 2 to 15;u. The common 

 size is 5fi. 



Polariscopic Properties. — In figure the grains are so 

 small and usually so slightlj' polariscopic that an inter- 

 ference figure can not always be made out; when seen it 

 is clear-cut and distinct. It is slightly to markedly ec- 

 centric. The lines are of the same size and distinct- 

 ness throughout their length, and are bent or otherwise 

 distorted. 



nil 1 e 1 • 1 ' ' ^ Curve of Reaction-Intensities of Starch of Ranunculus 



1 he degree of polarization is low. buibosus. 



With selenite the quadrants in most grains are not 

 well defined, are usually quite regular in shape, but unequal in size. The colors are not pure. 



Iodine Reactions.— With 0.25 per cent Lugol's solution the grains are colored a blue-violet 

 immediately and deeply; with 0.125 per cent solution the grains color well and the color deepens 

 quickly. The reaction is not quite so deep as that of R. ficaria. After heating in water until all 

 the grains are completely gelatinized, the solution is colored fairly well and the grain-residues deeply 

 to lightly with iodine. With an excess of iodine the capsules color a blue-violet. 



