GLADIOLUS TRITONIA. 



685 



gelatinized, but the larger grains are little if at all 

 affected by the reagent. 



The reaction with mercuric chloride begins in a few 

 of the smaller grains immediately. Complete gelatiniza- 

 tion occurs in about 2 per cent of the entire number of 

 grains and 3 per cent of the total starch in 5 minutes; 



in about 3 per cent of the grains and 4 per cent of the 

 total starch in 15 minutes; in about 4 per cent of the 

 grains and 5 per cent of the total starch in 30 minutes ; 

 little if any advance is observed in 45 and 60 minutes. 

 (Chart D483.) Only the smaller grains and rare 

 medium-sized grains are gelatinized. 



10. TRITONIA. 



This genus includes over 30 species of South African 

 bulbous plants, only a few of which are in cultivation. 

 The older generic name is Montbretia, and tritonias are 

 commonly known by this name. The genus is closely 

 related to Gladiolus, and some of the species have been 

 classified with the latter, as, for instance, T. lineata 

 Ker-Gawl as G. lineatus, and T. securigera Ker-Gawl as 

 G. securiger. 



Starches of the following parent-stocks and hybrid- 

 stocks were studied : 



35. T. pottsii Benth. (Montbretia pottsii Baker) (seed parent) , 

 T. crocosmia aurea Planch (pollen parent), and T. ci'ocos- 

 mceflora Lemoine (hybrid). 



The specimens were obtained from E. H. Krelage and 

 Son, Haarlem, Holland. 



35. STAKCHES OF TRITONIA POTTSII, T. CROCOSMIA 



AUREA, AND T. CROCOSM^EFLORA. 



TlUTONIA POTTSII (SEED PARENT). 



(Plate 20, fig. 118; Charts D 484 to D 504.) 



HISTOLOGIC PROPERTIES. 



In form the majority of the grains are simple and 

 the separated components of aggregates, with the excep- 

 tion of a few which either still remain in small aggre- 

 gates or which are permanently isolated grains. Rare 

 compound grains composed of 2 components are observed. 

 Well-defined pressure facets are present on the majority 

 of grains. The grains are generally regular, but some- 

 times irregular, and the irregularities are due to the fol- 

 lowing causes: (1) A small elevation located near the 

 distal margin; (2) the longitudinal axis may be slightly 

 shifted; (3) a small, concave depression, probably a 

 pressure facet, may be present at indefinite points on the 

 curved surface of a grain. The conspicuous forms of 

 the separated component grains are dome-shaped with 

 squared, pointed, or diagonal distal margin, ovoid with 

 squared or pointed distal margin, high bell-jar shaped, 

 sugar-loaf, polygonal, and nearly round with a concave 

 depression. The conspicuous forms of the permanently 

 isolated grains are nearly round, ovoid, ellipsoidal, round, 

 and broad triangular with rounded angles. The aggre- 

 gates usually consist of from 2 to 4 components of equal 

 or nearly equal size which are compactly arranged. Occa- 

 sionally they differ considerably in size, consisting, as 

 a rule, of 1 large and 1 small, or 1 large with 2 fair-sized 

 components, fitted compactly at the distal margin. The 

 grains are not flattened. 



The hilum is a small, slightly refractive, round or 

 lenticular-shaped spot, which is usually single and, rarely, 

 may be double. A small rounded cavity is sometimes 

 located at the hilum. The hilum is not usually fissured, 

 but occasionally small clefts are found which have the 

 following forms : (1) A single, straight or slightly curved 

 diagonal or transverse line; (2) two are arranged as 



soaring-bird figure; (3) two or three fissures often 

 extend obliquely from the hilum to the distal corners 

 of dome-shaped grains with squared or pointed base. 

 The hilum is either centric in position, or the range of 

 eccentricity is from 0.45 to 0.35, more often about 0.4, 

 of the longitudinal axis. 



The lamellce are not usually distinct. Most of them 

 are demonstrable and are fine to moderately fine, some- 

 times one located at varying distances from the hilum 

 is coarser, more distinct, and slightly refractive. Those 

 directly around the hilum may form circular rings, but 

 a very short distance outward they tend to follow the 

 outline of the grain. A marginal band in which the 

 lamellae are usually indistinct is sometimes present. On 

 the large, rounded, permanently isolated grains the num- 

 ber is occasionally found to be 14 to 18, and on the 

 separated dome-shaped grains 11 to 12. 



The size of the grains varies from the smaller which 

 are 4 by 3/*, to the larger nearly round permanently iso- 

 lated grains which are 34 by 32/t, and larger dome-shaped 

 separated components which are 28 by 28/u, in length and 

 breadth. The common size of the permanently isolated 

 grains is about 22 by 20/*, and of the dome-shaped 

 separated grains about 20 by 22/u, in length and breadth. 



POLARISCOPIO PROPERTIES. 



The figure is usually centric to slightly eccentric, 

 but is quite eccentric in a few grains; and is generally 

 distinct and clean-cut. The lines are moderately fine and 

 intersect both at right and oblique angles. They are 

 straight with broadening towards the margin in the 

 majority of the grains; but are moderately often bent 

 and occasionally bisected. Both double and multiple 

 figures are observed. 



The degree of polarization is high (value 70). It 

 varies in the different grains from moderate to very high. 

 There is also considerable variation in the same aspect 

 of a grain, sometimes one quadrant being quite low. 



With selenite the quadrants are usually well defined, 

 generally slightly unequal, and sometimes irregular. The 

 blue is generally pure, but the yellow is frequently not 

 pure throughout the entire quadrant. 



IODINE REACTIONS. 



With 0.25 per cent Lugol's solution, the grains do 

 not color at all with the exception of a few scattered 

 ones which immediately become a moderate dull blue- 

 violet, which deepens somewhat rapidly (value 10). With 

 0.125 per cent Lugol's solution the grains do not color at 

 first, nor do they take on the least color for some time. 

 After heating in water until all the grains are gela- 

 tinized and then adding 2 per cent Lugol's solution, 

 the grains color a light to moderately deep indigo-blue, 

 some with reddish tint, and the solution becomes moder- 

 ately deep indigo-blue. If the preparation is boiled for 

 2 minutes and then treated with an excess of 2 per cent 



