FOREST TREE SEED AND SEED COLLECTING 109 



16. The Determination of Genuineness 



On its receipt from the collector or dealer, forest tree seed should 

 be critically examined and compared with other seed of known 

 species. A hand lens that magnifies eight or ten diameters is 

 necessary in examining small seed. An examination is neces- 

 sary in order to determine whether the seed is true to name 

 or mixed with other species. Without an accurately labeled 

 collection of tree seed at hand it is difficult for the inexperienced 

 observer to determine the genuineness of many small-seeded 

 species. 



Tree seed should be purchased only from responsible collectors 

 and dealers who guarantee its genuineness. In many instances, 

 the external appearance of the seed affords sufficient diagnostic 

 characteristics. The more important of these are size, form, color, 

 and surface irregularities. Where external characteristics will not 

 suffice, the dissection of the seed is necessary. The color and 

 texture of the inner seed coat, the color and consistency of the 

 seed kernel, and the size and form of the embryo aid in identifi- 

 cation when the external appearance of the seed will not suffice. 

 As a specific example, from external appearance alone it is often 

 impossible to distinguish the acorns of scarlet oak from those of 

 black oak. The deep yellow color of the seed kernel in the latter, 

 however, will usually distinguish it from the former in which the 

 color is nearly white. 



17. The Determination of Viability 



The various methods for determining viability, or the percentage 

 of germinable seed under the most favorable conditions, may be 

 considered under the following heads: 



a. The determination of viability by direct inspection. 



b. The determination of viability by physical tests. 



c. The determination of viability by germination tests. 



The determination of viability by direct inspection and physical 

 tests is uncertain in results and should be used only in cases where 

 there is not time or opportunity for germination tests. With 

 species like red cedar, hornbeam, and tulip, because of the length 

 of tune required for germination, they are the only practical means 

 for judging the viability of the seed. 



