GENUS QUERCUS. 



429 



Differentiation of Certain Starches 

 Histological Characteristics. Continued. 

 Hitum Form, Number and Position. ContiiiueJ. 



Q. prinits: Same as in (^. 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 liilum 

 sometimes pre.sent. 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 hilum, 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. 



Latnellw 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. aiba, but demonstrable in smaller 

 percentage of grains. S 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 

 conmion-sized grains. 



Size. 

 Q. alba: From 4 to 32m, commonly 22^. 

 Q. muehlenberg^i: From 4 to 30m, commonly 16^. 

 Q. prinus: From 4 to 24^, commonly 16^. 

 y. rubra: From 4 to ISm, commonly 12/1. 

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



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 as 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. priniLs: Fair to quite high; the percentage of grains 



in which they are quite high is not so great as 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 Selenite Quadrants and Colors. 

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



shape, miequal in size. Colors generally pure. 

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



generally pure. 



of the Genus Quercus. Continued. 



Polariscopic Properties. Continued . 

 Polarization with Selenite Quadrants and Colors. Con'd. 



Q. prinus: 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 fight, much Ughter than in Q. alba; red- 

 violet. 



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



Staining Reactions. 

 With Gentian Violet. 

 Q. alba: Very fight. 



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

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



than in Q. alba. 

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

 Q. texana: Very fight, the same aa in Q. alba. 



With Safranin. 

 Q. alba: Very fight. 



Q. muehlenbergi: Very fight, 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: I,ight, sUghtly deeper than in Q. alba. 



Temperature op Gelatinization. 

 Q. alba: 60 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 64.26. 



Effects of Various Reagent-s. 



Reaction ivilh Chloral Hydrate-Iodine. 



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



4 minutes. 

 Q. ?miehlenhergi: Begins in 20 seconds; complete in prac- 



ticaUy all in 7 minutes. 

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



aU in 5 minutes. 

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



3 minutes. 

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



3 minutes. 



Reaction with Chromic Acid. 



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



Q. muehlenbergi: Begins immediately; complete in ma- 

 jority in 40 seconds, aU 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 aU 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. 



