138 HARSHBERGER— STUDY OF THE CLOVERS. 



pratensc perenne (18.5), pratense y^ medium = Sutton's cowgrass 

 (21), pratense y^ pratensey^ medium = Sutton's giant hybrid cow- 

 grass (19.5), procumbens (2.5, 2.9, 5), reclinatum (30, 31), reflexum 

 (6, 6.5), repens (2, 3, 3.5, 3.7, 5.5, 5.5, 7, 7, 7, 7.5, 8), repens var. 

 macrorhiza (5.5), repens perenne (7.5), repens var. (4.7), resupi- 

 natum (8.5, 10, 11), rubens (18, 18.5, 19.5, 21, 22.5, 23.5), scabrum 

 (i, 2, 4.5), spadiceum- (5), spum^osum (2.5), squarrosum (15), 

 striatum (20, 20.6), suaveolens (16.5), subtcrraneum (26, 34, 

 119.6^), tridentatum (13.5). If we classify the species according to 

 the weight of their seeds into Hght-seeded, medium-seeded, heavy- 

 seeded, we would have the following arrangement of them : 



Light-seeded Clovers. — agrarium, arvense, aureum, balanscB, boc- 

 coni, campestre, cernuum, dubium, elegans, filiforme, glomeratum, 

 hybridum, johnstoni, minus, montanum, nivale, patens, perreymondi, 

 procumbens, reflexum, repens and varieties, scabrum, spadiceum, 

 spumosum. 



M editun-weight Seedsi — alpcstre, altissimum, angustifolium, lupi- 

 naster, maritimum, medium, pratense, squarrosum, suaveolens, tri- 

 dentatum. 



Heavy-seeded Clover s.-^alexandrinum, incarnatum, pannonicum, 

 reclinatum, rubens, striatum, subterraneum. 



The weight of seeds is an important matter to know in buying 

 seeds for farming operations by bulk, and also it can be used in 

 helping to identify doubtful seed samples, as there are general specific, 

 differences in the weight of seeds. There is some degree of correla- 

 tion between the weight of clover seeds and their size. The larger 

 seeds are heavier than the smaller ones. It is probable that the dif- 

 ferences in the weight of two samples of the same species of clover 

 are due also to a difference in their age. The older seeds, having lost 

 water in drying, are, of course, lighter than the younger seeds, which 

 have not dried out to the same extent. The variation in weight may 

 be due to the fact that they have been derived from different coun- 

 tries, and, therefore, grew under totally different conditions. 



1 This apparently large discrepancy is due to the fact that the seed size and 

 weight varied more in this species than in any other. 



