GENUS QUERCUS. 



429 



Differentiation of Certain Starches of the Genus Quercus. — Continued. 



Histological Characteristics. — Continued. 

 HUum — Form, Number and Posilum. — Continued. 



Q. prirms: Same as in Q. alba, but the hilum more often 

 demonstrable and the fissure when present not 

 so deep. Position usually eccentric 0.3 to 0.4. 



Q. rubra: Occasionally the same as in Q. alba, but hilum 

 is more often demonstrable from which 1 longi- 

 tudinal cleft with 2 to 3 pronged divisions, or 2 

 to 3 parallel longitudinal clefts proceed; a short 

 transverse cleft through or just beneath the hilum 

 sometimes present. Position usually eccentric 

 0.3 to 0.4. 



Q. texana: Occasionally the same as Q. alba, but more 

 often there are 2 to 3 parallel longitudinal fissures 

 or one proceeding from the liilum, which divides 

 into 2 or 3 pronged branches. A transverse cleft 

 through or just beneath the hilum sometimes 

 present. Position usually eccentric 0.3 to 0.4. 



LameUoe — General Characteristics and Number. 



Q. alba: Not always distinct, when seen are rather coarse 

 continuous rings, following the outline of the grain; 

 secondary sets of lamellae more indistinct than 

 primary observed on most irregular grains. 8 to 

 10 on common-sized grains. 



Q. muehlenbergi: Same as in Q. alba. 6 to 10 on common- 

 sized grains. 



Q. prinus: Same as in Q. oZfca, but demonstrable in smaller 

 percentage of grains. 8 counted on common-sized 

 grains. 



Q. rubra: Not demonstrable. 



Q. texana: Rarely demonstrable, when observed similar 

 in character to those of Q. alba. 8 counted on the 

 common-sized grains. 



Size. 

 Q. alba: From 4 to 32j«, commonly 22;i. 

 Q. muehlenbergi: From 4 to 30;i, commonly 16/i. 

 Q. prinus: From 4 to 24;a, commonly 16/j. 

 Q. rubra: From 4 to 18/i, commonly 12^. 

 Q. texana: From 4 to 20;x, very rarely 26m, commonly 12jti. 



PoLARiscopic Properties. 



Figure. 



Q. alba: Sometimes centric, but usually eccentric, and 



commonly in the form of a cross or of the bean 



type; distinct, frequently irregular. 

 Q. muehlenbergi: Same as in Q. alba, but more regular, and 



fewer bean type. 

 Q. prinus: Same as in Q. alba, but more regular, and less 



of the bean type. 

 Q. rubra: Same as in Q. alba, but more regular, and the 



bean type is very rare. 

 Q. texana: Same aa in Q. alba, but slightly more regular, 



and fewer of the bean type. 



Degree of Polarization. 

 Q. alba: Fair to quite high. 

 Q. muehlenbergi: Fair to quite high, smaller percentage 



of grains in which they are quite high than in 



Q. alba. 

 Q. prinus: Fair to quite high; the percentage of grains 



in which they are quite high is not so great aa in 



Q.alba. 

 Q. rubra: Low to fairly high, frequent variation in the 



same aspect of a given grain. 

 Q. texana: Fair to fairly high; frequent variation in the 



same aspect of a given grain. 



Polarization with Selenile — Quadrants and Colors. 

 Q. alba: Quadrants usually well-defined, irregular in 



shape, unequal in size. Colors generally pure. 

 Q. muehlenbergi: Quadrants same as in Q. alba. Colors 

 generally pure. 



PoLARiscopic Properties. — Continued. 

 Polarization with Selenile — Quadrants and Colors. — Con'd. 



Q. printis: Quadrants same as in Q. alba. Colors gener- 

 ally pure. 



Q rubra: One of the quadrants is frequently not well- 

 defined; occasionally the same as in Q. alba. 

 Colors generally pure. 



Q. texana: Quadrants same as in Q. rubra. Colors gener- 

 ally pure. 



Iodine Reactions. 

 Intensity and Color. 



Q. alba: Fair; blue-violet. 



Q. muehlenbergi: Fair, the same as in Q. alba; blue-violet. 



Q. prinus: Light, lighter than in Q. alba; violet, more 

 reddish in tint and deepens more slowly than in 

 Q. alba. 



Q. rubra: Very light, much lighter than in Q. alba; red- 

 violet. 



Q. texana: Light, lighter than in Q. alba; red-violet. 



Staining Reactions. 

 With Gentian Violet. 

 Q. alba: Very light. 



Q. muehlenbergi: Very light, the same as in Q. alba. 

 Q. prinus: Very light, less in the majority of the grains 



than in Q. alba. 

 Q. rubra: Very light, the same as in Q. alba. 

 Q. texana: Very Ught, the same as in Q. alba. 



With Safranin. 

 Q. alba: Very light. 



Q. muehlenbergi: Very light, about the same as in Q. alba. 

 Q. prinus: Very light, less than in the majority of the 



grains of Q. alba. 

 Q. rubra: Very light, sUghtly deeper than in Q. alba. 

 Q. texana: light, slightly deeper than in Q. alba. 



Temperature op Gelatinization. 

 Q. alba: 6Q to 61.5° C, mean 60.75°. 

 Q. muehlenbergi: 62.5 to 64° C, mean 63.75°. 

 Q. prinus: 64 to 65.8° C, mean 64.75°. 

 Q. rubra: 62.5 to 63.5° C, mean 63°. 

 Q. texana: 64 to 64.5° C, mean 64.25°. 



Effects op Various Reagents. 

 Reaction with Chloral Hydrate-Iodine. 



Q. alba: Begins at once; complete in practically all in 

 4 minutes. 



Q. muehlenbergi: Begins in 20 seconds; complete in prac- 

 tically all in 7 minutes. 



Q. prinus: Begins in 30 seconds; complete in practically 

 all in 5 minutes. 



Q. rubra: Begins at once; complete in practically all in 

 3 minutes. 



Q. texana: Begins at once; complete in practically all in 

 3 minutes. 



Reaction with Chromic Acid. 



Q. alba: Begins immediately; complete in 25 seconds. 



Q. muehlenbergi: Begins immediately; complete in ma- 

 jority in 40 seconds, all in 60 seconds. 



Q. prinus: Begins immediately; complete in majority in 

 35 seconds, all in 60 seconds. 



Q. rubra: Begins immediately; complete in all but a 

 rare resistant grain in 25 seconds, in all in 50 

 seconds. 



Q. texana: Begins immediately; complete in all in 20 

 seconds. 



Reaction with Pyrogallic Acid. 

 Q. alba: Begins immediately; complete in 25 seconds. 

 Q. muehlenbergi: Begins immediately in half of the grains; 

 complete in 60 seconds. 



