GENUS ACT^A. 



861 



STARCHES OF HELLEBORACEL. 



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

 represented : Actsea, Cimicifuga, and Eranthis. 



The Helleboraceoe comprise about 20 genera and 130 species of herbaceous perennials and 

 annuals. 



GENUS ACT/EA. 



The genus Aclcea includes a few both Old World and New World species which are popularly 

 known as the black, white, or red baneberry, cohosh, or herb-christopher. Starches from two 

 sources were studied: A. alba Mill. (A. rubra Bigel.), the white baneberry, a native North American 

 plant; and A. spicata var. rubra Ait. (A. rubra Willd.), the red baneberry, also American. 



IGV 

 S 



PS O PA ( 

 PC PS 



STARCH OF ACT^A ALBA. (Plate 95, fig. 569. Chart 374.) 



Histological Characteristics. In form the grains are simple. No compound grains are observed, 

 bat there are many aggregates and clumps. Many grains show one or more pressure facets, but 

 without the sharpness of angle noted in faceted grains of other genera generally. The surface of 

 many grains is irregular as the result of pressure. The conspicuous forms are round, ovoid, rounded 

 with one part flattened or pointed, dome-shaped to hemispherical ; also triangular with well-rounded 

 angles, and ovoid with the distal end sharply pointed, sometimes polygonal with the angles rounded, 

 and various indefinite forms. Many appear like disks, and some Uke concave disks. 



The kilum is often invisible, but when observed is seen to be in the form of a round or lenticular, 

 indistinct spot, sometimes centric but usually eccentric from slightly to one-third of the longi- 

 tudinal axis. A depression, which scarcely amounts to a 

 fissure, often crosses the hilum. 



No lamellcB are discernible. 



The grains vary in size; the smaller are 1 by l/n; the 

 larger are 11 by 9/i in length and breadth, or 13 by 12/i 

 in length and breadth; the common size is 8 by 7/* in 

 length and breadth. 



Polariscopic Properties. The figure is usually more 

 or less eccentric and generally indistinct. Its lines are 

 rather thick but generally straight. 



The degree of polarization is low. It varies in dif- 

 ferent grains and sometimes in the same aspect of a grain. 



With selenite the quadrants are fairly well defined, 

 slightly irregular in shape, and unequal in size. The 

 colors appear to be pure but dull. 



Iodine Reactions. With 0.25 per cent Lugol's solu- 

 tion the grains all color a very deep blue- violet; with 

 0.125 per cent solution they color fairly deeply, and the 

 color deepens rapidly. After heating in water until the 

 grains are completely gelatinized, the solution colors fairly and the gelatinized grains very deeply 

 on the addition of iodine. After boiling for 2 minutes the solution colors very deeply and the grain- 

 residues but little or not at all. The capsules all color a violet with an excess of iodine. 



Staining Reactions. With gentian violet the grains begin to stain lightly at once and in 30 min- 

 utes are rather lightly stained. 



With safranin the grains begin to stain very lightly at once and in 30 minutes are lightly stained. 



Temperature Reaction. The temperature of gelatinization is 55" to 57 C, mean 56. 



Effects of Various Reagents. With chloral hydrate-iodine reaction begins at once and is over in 

 45 seconds. It appears in the form of a darkening and swelling of the distal end of the grain, fol- 

 lowed by extension all about the margin; then the starch of the interior is affected and the whole 



Curve of Reaction-Intensities of Starch of Actsa alba. 



