736 



STARCHES OF IKIDACEJB. 



Differentiation of Certain Starches 



TBMPERATDBE of GEla.TINIZATION. 



2*. eroeata: 82 to 83° C, mean 82.5°. 



T. erocaia var. lilacina: 81 to 82.5° C, mean 81.76°. 



T. erocaia var. rosea: 81 to 82° C, mean 81.5°. 



T. ttcurigera: 80 to 82° C, mean 81°. 



T. potttii: 72 to 73° C, mean 72.5°. 



T. erocosmaftora: 72 to 74° C, mean 73°. 



Effects of VARions Reagents. 

 Reaction with Chloral Hydrate-Iodine. 



T. eroeata: Begins in half to 2 minutes; complete in 

 25 minutes. 



T. erocaia var. lilacina: Begins in 1 to 3 minutes; com- 

 plete in 30 minutes. 



r. eroeata var. rosea: Begins in three-fourths to 2 

 minutes; complete in 22 minutes. 



T. aecurigera: Begins in 1 to 2 minutes; complete in 30 

 minutes. 



T. pottsii: Begins in many in a minute; complete in 

 four-fifths in 35 minutes, and in almost aU in 1}4 

 hours. 



T. erocosnuBJlora: Begins in most in 1}^ minutes; com- 

 plete in three-fourths in 1 hour. 



Reaction with Chromic Aeid. 

 T. eroeata: Begins in 30 to 90 seconds; complete in 20 



minutes. 

 T. eroeata var. lilacina: Begins in 30 seconds; complete 



in 30 minutes. 

 T. eroeata var. rosea: Begins in 30 seconds; complete in 



15 minutes. 

 T. ucurigera: Begins in 30 to 60 seconds; complete in 



18 minutes. 

 T. pottsii: Begins in 30 seconds; complete in 4 minutes. 

 T. crocosmaflora: Begins in most in 45 seconds; complete 



in 4 minutes. 



Reaction with PyrogaUie Acid. 

 T. eroeata: Very slight general reaction in 15 minutes; 



a very few grains are completely gelatinized in 



45 minutes. 

 T. eroeata var. lilacina: Verjr slight general reaction in 



10 minutes; a few grains are partially gelatinized 



in 45 minutes. 



of the Genus Tritonia. — Continued. 



Effects of Various Reaqbnts. — (Continued. 



Reaction with PyrogaUie Acid. — Continued. 

 T. eroeata var. rosea.' Very slight general reaction in 10 



minutes; slight general reaction in 10 minutes; 



1 or 2 completely gelatinized in 25 minutes. 

 T. securigera: Very shght general reaction in 7 minutes; 



one-sixth fully or partially gelatinized in 17 



minutes. 

 T. pottsii: Begins in all in 45 seconds; complete in 12 



minutes. 

 T. crocosnueflora: Begins in most in 60 seconds; complete 



in 12 minutes. 



Reaction with Ferric Chloride. 



T. erocaia: Begins in some in 4 minutes; practically com- 

 plete in 40 minutes. 



T. erocaia var. liladna: Begins in all in 6 minutes; not 

 complete in 60 minutes. 



T. erocaia var. rosea: Begins in all in 7 minutes; not 

 complete in 45 minutes. 



T. securigera: Begins in all in 5 minutes; complete in 

 35 minutes. 



T. pottsii: Begins in some in \]/i minutes; complete in 

 almost all in 20, and in all in 37 minutes. 



T. crocosmosflora: Begms in a few in IJ^ minutes; com- 

 plete in practically all in 45 minutes and in all in 

 75 minutes. 



Reaction with Purdy'a Solvtion. 



T. erocaia: Begins in all in 2 minutes; complete in 

 three-fourths in 45 minutes; incomplete in a few in 

 60 minutes. 



T. eroeata var. lilacina: Begins in all in 4 minutes; com- 

 plete in all in 2 hours. 



T. erocaia var. rosea: Begins in all in 12 minutes; com- 

 plete in four-fifths in 1?^ hours. 



T. securigera: Begins in all in 2 minutes; complete in 

 four-fifths in 1 J^ hours. 



T. pottsii: Slightly in a few in IJ^ minutes; all are 

 partially gelatinized and a few nearly completely 

 gelatinized in 1 J^ hours. 



T. crocosmaflora: SUghtly many in 2 minutes; all are 

 partially and a few nearly completely gdatinized 

 m IJ^ hours. 



NOTES ON THE STARCHES OF TRITONIA. 



Compaxing these starches it will be observed that on the basis of the gross histological charac- 

 ters the specimens may be divided into three groups which consist of T. eroeata and its two varieties, 

 T. securigera, and T. pottsii and T. crocosmmflora, respectively. This is in accord with botanical 

 peculiarities. The same grouping holds good for the reactions, differences being quite marked in 

 almost every reaction. It is of particular interest to note the marked differences in the tempera- 

 tures of gelatinization of T. erocaia and its varieties and T. securigera as compared with those of 

 T. pottsii and its hybrid, a difference of 8.7°; and also that while T. eroeata and its varieties and T. 

 securigera correspond in their temperatures of gelatinization they differ appreciably in their reactions. 

 T. pottsii and its hybrid appear to stand distinctly apart from the other members of the genus in 

 the peculiarities of their starches, yet there is the same type of reaction-curve. 



GENUS FREESIA 



The Freesias are bulbous plants, natives of the neighborhood of the Cape of Good Hope and 

 closely allied with Tritonia and Gladiolus. Less than a half a dozen species and a few varieties are 

 in common cultivation. It seems probable that F. refracta is the parent stock of the genus. Starches 

 from 2 varieties of 1 species were examined : F. refracta var. alba and F. refracta var. leichUinii. 



STARCH OF FREESIA REFRACTA VAR. ALBA. (Plate 73, figs. 433 and 434. Chart 285.) 

 Histological Characteristics. — In form the grains are simple and occur isolated or as aggregates 

 consisting of two, three, four, or more components. On all the isolated grains pressure facets are 

 found that have been parts of aggregates. The surface tends to be rounded and smooth. The 



