608 



STARCHES OP LILIACEiE. 



on the whole, are recorded in the degree of polarization. In the temperatures of gelatin! zation 

 the range is from 61° to 70°, a difference of 9°. In the reactions with Purdy's solution all the starches 

 were found to be resistant and gelatinization was incomplete at the end of an hour; but marked 

 differences were noted in the intensities of the reactions in the interim, thus showing more or less 

 marked variations in the sensitivities. The reaction-curves of the various Brodicm, while exhibit- 

 ing a common type, are sufficiently different to render the diagnosis of each species quite easy. 



In reference to the three groups of Brodicea it does not appear that there are any obvious gross 

 histological peculiarities common to each group which would differentiate one from the others, but 

 in the reactions the grouping is very evident and entirely in accord with that of the horticulturist. 

 In the degree of polarization the reactions of the three groups average alike. In the iodine and gen- 

 tian-violet reactions the first group shows, on the whole, distinctly less sensitivity than the second 

 and third groups. In the safranin reactions the responses of the second group are, on the whole, 

 better than those of the first and third. In the chloral hydrate-iodine reactions the sensitivity of 

 the second group is, as a whole, distinctly lower than that of the first and second, and there is a simi- 

 lar indication in the chromic-acid reactions. In the pyrogallic-acid and ferric-chloride reactions 

 the sensitivity of the first group is distinctly greater than in the second and third. In the reactions 

 with Purdy's solution the order of sensitivity is first, third, and second groups. There are, there- 

 fore, positive distinctions as regards both species and groups. 



GENUS TRITELEIA. 



The Triteleias have been included by some botanists among Milla and Brodicea, and by others 

 regarded as a distinct genus. The species are South American and probably to be looked upon as the 

 southern representatives of MUla and Brodicea of North America. Because of certain peculiarities 

 they may be grouped as a distinct genus. T. uniflora Lindl. {Milla uniflora Grab., Brodicea uniflora 

 Baker), popularly known as the spring star-flower, is a well-marked species and the only one under 

 cultivation. From it starch was obtained. 



STARCH OF TRITELEIA UNIFLORA. (Plate 49, figs. 289 and 290. Chart 183.) 



Histological Characteristics. — In form the grains are simple and nearly always isolated. They 

 are usually marked at the distal end, and less often at one side, with pressure facets. Their surface is 

 sometimes somewhat irregular, owing to pressure facets and irregularities in the development of differ- 

 ent parts. The conspicuous form is the dome-shaped, which is often long, and the proximal end may 

 be larger than the distal end, which is flattened. There 

 are also hemispherical with flat or pyramidal bases, ovoid, 

 oval, and spherical. The grains are of the same thickness 

 as breadth, and therefore round when viewed on end. 



The hilum is always fissured, and distinct. It is 

 eccentric about one-third or less, often two-fifths, of the 

 longitudinal axis, and is usually in the median line. There 

 are no multiple hila. There may be one clean-cut, trans- 

 verse, straight fissure, but usually two or more. If two, 

 they are arranged so that three lines appear to radiate 

 from a central cavity; if more, they are in an irregularly 

 stellate form. The fissures are rarely ragged. 



The lamella are fairly distinct, coarse, continuous 

 rings, which usually follow the outline of the margin only 

 when located near it; but in some grains this relationship 

 is noted even when they are near the hilum. They are 

 coarser near the margin, but more distinct near the hilum. 

 There are 8 to 10 on the larger grains. 



The grains vary in size from 4 to 26^. The common 

 size is 18^. 



Polariscopic Properties. — The figure is eccentric, distinct, fairly clear-cut, and usually some- 

 what irregular. Sometimes the lines are rather blurred, and may be bent or otherwise distorted. 



The degree of polarization is high. It varies in different grains, being higher in the larger grains 

 and in different aspects of the same grain. It is higher when the grain is viewed from the end or edge. 



QartNo. 183. 



Curve of Reaction-Intensities of Starch of Triteleia 

 uniflora. 



