616 



STAECHES OP CONVALLAEIACEiE. 



STARCHES OF CONVALLARIACE^E. 



PC PS 

 5 



Class, Monocotyledones. Order, Liliales. Family, Convallariaceae. Genera 

 represented: Convallaria, Trillium. 



ConvaUariacecB is very closely allied to Liliacece, and by many botanists its members are classed 

 among the latter. It includes less than a dozen genera and about 550 species, all of which are natives 

 of North America, Europe, and Asia. 



GENUS CONVALLARIA. 



This genus includes but a single species, Convaliaria majalis Linn., from which have arisen a 

 number of varieties. The Uly-of-the-valley is a native of the Southern Alleghenies and part of 

 temperate Europe and Asia. 



STARCH OF CONVALLARIA MAJALIS. (Plate 50, figs. 295 and 296. Chart 201.) 



Histological Characteristics. — In form the grains are simple, with the exception of rare compound 

 grains and a few small aggregates and clumps. Well-marked pressm-e facets are frequently found. 

 The grains are either rather small or quite large, the former predominating. They are generally 

 regular, but variations in the contour and in the length of the sides may occur, due to pressure. 

 The conspicuous forms are nearly round to round, dome-shaped, ellipsoidal, ovoid, broadly triangular 

 with curved base and rounded angles, bean-shaped, somewhat mussel-shell-shaped, and lenticular. 

 The small grains are not flattened, but the large broadly 

 triangular and somewhat mussel-shell-shaped are much 

 less thick than broad, hence when seen on end the small 

 grains are round and the large grains elliptical. 



The hilum is a clear round spot, usually slightly to 

 one-fourth eccentric of the longitudinal axis. The small 

 grains are not fissured, but in the large, broad, triangu- 

 lar, and shell-shaped may be fissured by three clefts 

 which form a Y-shaped figure; or one figure extends 

 from each side of the hilum; or a group of clefts form- 

 ing either a stellate or a thorn-shaped figme may be 

 observed. In the large ovoid and bean-shaped grains 

 generally one large fissure passes from the hilum towards 

 the distal end. 



The lamellce are very indistinct, but occasionally they 

 can be clearly observed on the larger grains, where they 

 are not demonstrable near the hilum, but those which can 

 be distinguished are fairly coarse and follow the outline 

 of the grain. One of these lamellae is often coarser and 

 more refractive than the others. 



The grains vary in size; the smaller are 3 by 2/z; the larger are 44 by 26/i (ovoid) and 40 by 44/i 

 (broadly triangular) in length and breadth. The common size is 8 by 7m in length and breadth. 



Polariscopic Properties. — The figure is usually slightly to quite eccentric. The lines in the 

 smaller grains generally cross obliquely and are rather fine and straight, but in the larger they are 

 coarse and cross each other obliquely; they may be straight, but are frequently bent and sometimes 

 bisected. 



The degree of polarization is fair. It is low to fair in the small grains, and high to very high 

 in the large grains. Since the proportion of small grains is so much greater the mean degree of 

 polarization is placed at fair. There is frequently a variation in the same aspect of a given grain. 



Curve of Reaction-Intensities of Starch of Convallaria 

 majalis (small grains). 



