570 



STARCHES OF LILIACEiB. 



GENUS HYACINTHUS. 



HyadrUhus is a genus of bulbous plants which includes over 30 species and very many varieties, 

 there being also hundreds of "named" garden forms. They are natives of Central Europe, Asia, 

 and Africa. The common garden forms have had their origin in natives of the Mediterranean 

 region. Quite a number of members of other genera of Liliacece are popularly known as hyacinths, 

 as, for instance, certain species of Scilla, Brodicea, Muscari, and Camassia. The water-hyacinth 

 (Eichhomia) belongs to an entirely different family. The starches of three horticultural varieties 

 were examined: H. orientalis var. alba superbissima Hort., which is probably a form of H. orientalis 

 Linn. ; and two kinds of the Roman hyacinths, the white and the Italian, both of which are prob- 

 ably forms of H. orientalis var. albtdus Baker (H. albulus Jord., H. romanus Hort.). 



STARCH OF HYACINTHUS ORIENTALIS VAR. ALBA SUPERBISSIMA. 

 (Plate 41, figs. 241 and 242. Chart 159.) 



Histological Characteristics. — In form, both simple and compound grains are present. Many 

 aggregates are noted as doublets, triplets, or a larger number of components, the doublets often 

 consisting of one large and one very small grain. Isolated grains with pressure facets are occasion- 

 ally observed and there are a few small clumps. The surface of the simple grains is often irregular, 

 owing chiefly to protuberances, some of which are in the form of secondary lamellse, and some as 

 rounded or nipple-like prominences. Protuberances are sometimes found on the compound grains. 

 The conspicuous forms are ovoid, having a rounded proximal end and broadened and somewhat 

 flattened at the distal end, ellipsoidal, nearly round, and pyriform. From this type transition forms 

 to the clam-shell shape and mussel-shell shape, such as are 

 found in Muscari, may be observed. There are also pyri- 

 form, conical, finger-shaped, triangular and quadrangu- 

 lar with rounded angles, dome-shaped, and various indefi- 

 nite forms. When viewed on edge, many grains are seen 

 to be narrower at the distal than at the proximal end. 



The hilum is a large round or lenticular spot, eccen- 

 tric about two-fifths to one-third, generally two-fifths, in 

 all forms except the round. There are frequently 2 or 

 more hila in a single grain. Very often fissm-es or cavities 

 occur at the hilum. The fissuration may be noted as 

 being in the form of a single transverse or longitudinal 

 fissure, but usually both transverse and longitudinal fis- 

 sures are present in the form of a cross or T. Irregular 

 figures consisting of several short fissures, usually thorn- 

 shaped or stellate, are also found. The fissures may be 

 clean-cut or ragged. Fissures may be seen separating 

 two hila in a single grain. 



The larmllce are quite coarse. They are distinct, 

 complete rings near the hilum, and towards the margin 

 and the distal end they tend to assume the form of the outlines of the grain and may be incomplete. 

 There may be one but usually two very distinct lamellse. In the latter case one is about one-third, 

 the other about two-thirds of the distance from the hilum to the distal margin. There are about 

 12 to 14 lamellse in the larger forms. 



The grains varj' in size from 3 to 34/i. The common size is 26 by 24ai in length and breadth. 



Polariscopic Properties. — The figure is eccentric, except in the round forms. It is distinct and 

 fairly clear-cut. Its lines are broad, somewhat broader towards the margin; they are usually straight, 

 but may be bisected, bent, or otherwise distorted, the distortion probably being due to the presence 

 of multiple component grains. Double figures are sometimes observed. 



The degree of polarization is high. It varies in different grains, in different aspects of the same 

 grain, and also in parts of the same aspect of a grain. 



With selenite the quadrants are fairly well defined, usually somewhat irregular in shape, and 

 unequal in size. The colors are mostly pure, though in quite a number the blue has a greenish tinge. 



Iodine Reactions. — With 0.25 per cent Lugol's solution the grains color a fairly deep blue- 

 violet, which deepens rather slowly; with 0.125 per cent solution they color lightly at first and the 



Curve of Reaction- In tensities of Starch of Hyacinthua 

 orientalis var. alba superbissima. 



