GLADIOLUS. 



075 



9. GLADIOLUS. 



This genus of iridaceous, cormous, or bulbous 

 plants includes about 140 species, mostly natives of 

 Cape Colony and Natal. About 15 species are natives 

 of the Mediterranean region, and a few have been found 

 in the mountains of tropical Africa. Most of the culti- 

 vated forms are species or hybrids referable to the Soutli 

 American group and represented chiefly by G. cardinalis, 

 G. fioribundus, G. psittacinus, and G. blandus. Gladi- 

 olus and Tritonia are closely related genera. (See 

 Tritonia.) 



Starches of the following parent-stocks and hybrid- 

 stock were studied : 



34. O. cardinalis Curt, (seed parent), 0. tristis Linn, (pollen 

 parent), and G. colvillei (hybrid). 



The specimens were obtained from E. H. Krelage and 

 Son, Haarlem, Holland. 



34. Starches of Gladiolus cardinalis, G. tristis, 



and g. colvillei. 



Gladiolus cardinalis (Seed Parent). 



(Plate 20, fig. 115; Charts D 463 to D 483.) 

 Histologic Properties. 



In form most of the grains are simple and appear as 

 aggregates of usually 2 to 6, rarely 12, components, with 

 the exception of a few which are separated components 

 of aggregates or have remained isolated throughout their 

 life-history. Compound grains consisting usually of 2 

 components inclosed in a few common lamella? are occa- 

 sionally observed. Sharply defined pressure facets are 

 present on the separated grains. The surface of the 

 grains is usually regular, but occasionally there is found 

 either a slight, rounded elevation, or reticular markings 

 at some point, the latter probably indicating the previous 

 attachment of small grains to a large one. The con- 

 spicuous forms of the aggregates (composed usually of 

 about equal-sized components) are ellipsoidal, nearly 

 round, rounded triangular, and rounded quadrangular. 

 In addition there are aggregates of 1 large arid 1 or more 

 small components, and rarely aggregates with compo- 

 nents in linear arrangement in the form of a straight or 

 slightly bent rod with curved ends. The conspicuous 

 forms of the few separated grains are dome-shaped with 

 either squared or pointed base, and polygonal. The con- 

 spicuous forms of the permanently isolated grains are 

 round, nearly round, and ellipsoidal. The grains are not 

 flattened. 



The hilum is a small, round, oval, or lenticular, 

 usually non-refractive, spot. Multiple hila are occasion- 

 ally found. A small rounded cavity, a short transverse 

 cleft, or a group of clefts occasionally appear at the hilum. 

 The clefts are usually arranged in a soaring-bird, a 

 cruciate, or a thorn-shaped figure. Fissures which pass 

 obliquely towards the distal corners of the grains fre- 

 quently proceed from the hilum. The hilum is either 

 centric or has a range of eccentricity from 0.45 to 0.35, 

 commonly about 0.4, of the longitudinal axis. 



The lamella are not always demonstrable, but are 

 moderately distinct in some of the grains. The lamella 

 nearest the hilum usually is found in the form of a circu- 

 lar ring but the remainder follow the outline of the grain. 

 They are moderately fine — often with one somewhat more 

 distinct and coarser, located at varying distances from the 



hilum. Occasionally a refractive marginal border or a 

 rounded elevation at some point on the grain is observed 

 in which the lamelhe are not always demonstrable, but, 

 when made out, they are coarser and more sharply defined 

 than those of the main body of the grain. These lamellae 

 probably represent a secondary set. The number of 

 lamellae on the larger permanently isolated and com- 

 ponent grains ranges from 10 to 14 on the components of 

 aggregates more often 8 to 10. 



The size of the grains varies from the smaller isolated 

 grains which are 3 by 2/x, to the larger permanent iso- 

 lated grains which are 2G by 25/*, and the larger aggre- 

 gates of the more common doublet type 48 by 3G/x, in 

 length and breadth. The common size of the permanent 

 isolated is about 22 by 20/j., and the common size of the 

 doublet is about 34 by 20/x in length and breadth. 



Polariscopic Pboperties. 



The figure varies from centric to quite eccentric, with 

 more of the former, and is usually distinct and clean-cut. 

 The lines are fine and many intersect either at a right 

 angle or obliquely — more figures with former arrange- 

 ment. In the figures of the isolated grains the lines are 

 usually straight, but in the numerous double and multi- 

 ple figures they are frequently bent and bisected. 



The degree of polarization is high to very high (value 

 85). There is considerable variation in the different 

 grains, and occasionally a slight variation in the same 

 aspect of a given grain. 



With selenite the quadrants are sharply defined, and 

 are often slightly unequal in size and irregular in shape, 

 but are regular and equal in some of the grains, especially 

 the permanently isolated ones. The colors are usually 

 pure, but occasionally indicate impurity by a greenish 

 tinge to both colors. 



Iodine Reactions. 

 With 0.25 per cent Lugol's solution the grains color a 

 moderate to deep (value GO) blue-violet which becomes 

 bluer in tint as it deepens rapidly. With 0.125 per cent 

 Lugol's solution the grains color a light blue-violet, some 

 of which deepen moderately rapidly, while others show 

 very little if any change. After heating in water until 

 all the grains are gelatinized and then adding 2 per cent 

 Lugol's solution, most of the gelatinized grains color a 

 light to moderately deep indigo-blue, with a few moder- 

 ately deep, and the solution a moderately deep indigo- 

 blue. If the preparation is boiled for 2 minutes, and 

 then treated with an excess of 2 per cent Lugol's solution, 

 the grain-residues color a deep blue with reddish tint, 

 most of the capsules a deep heliotrope and some wine-red, 

 and the solution a very deep indigo-blue. 



Aniline Reactions. 



With gentian violet the grains stain very lightly 

 at once, and in half an hour they are moderately colored 

 (value 50), and an occasional grain having a delicate 

 border of deeper color, deeper than in 67. tristis. 



With safranin the grains stain lightly at once, and in 

 half an hour they are moderately colored (value 53), and 

 an occasional grain with a delicate border of deeper color 

 as in reaction with gentian violet. The color with this 

 stain is a little deeper than with gentian violet, and 

 deeper than in G. tristis. 



