170 On the Vitalitii of Farm Seeds. 



of vitality is governed hy the more or less effective protection 

 of the embryo. (Plate I.) 



II. Grasses. — For the sake of clearness, the grasses have 

 been placed in two diagrams, one containing the best pasture 

 grasses, the other those of less value. Though the death of all 

 the samples occurred between the eighth and the thirteenth 

 years, not a great range of variation, yet the manner in which 

 the loss of vitality developed is very diverse. There are three 

 main types — the first, represented by timothy and tall oat-grass, 

 where the vitality' is well maintained for the first four years, 

 and thereafter di-ops rapidly, much as in the case of the barley 

 and wheats. The second, of which hard fescue and sheep's 

 fescue are the most characteristic representatives, drops rapidly 

 from the first to a point below 10 per cent., but then remains 

 practically stationary for a year or two before the vitality 

 disappears altogether. Lastly, some grasses have a fairly steady 

 loss of. vitality from first to last, the typical instance being 

 Italian rye-grass, meadow fescue being a somewhat less perfect 

 example of this group. The other grasses give curves more or 

 less related to these three types. (Plates II. and III.) 



III. Clovers. — The three true clovers (red clover, white 

 clover, and alsike) have a characteristic curve : very little loss 

 of vitality during the first three or four years, then a rapid loss 

 for another four years or so, and finally, the last 10 per cent, 

 of germinating power is only slowly lost during the space of 

 another three or four years. The red clover retains its vitality 

 best at the start, the white clover has the least rapid loss during 

 the middle period, and the alsike holds more tenaciously to the 

 last 10 per cent, of its germinating power. Trefoil loses at a 

 very steady rate from first to last, and sainfoin almost as 

 steadily; while lucerne has a very curious curve, losing heavily 

 at first, and then keeping practically level from the fifth to the 

 ninth year. (Plate IV.)" 



IV. Turnip and its Allies. — The special feature here is the 

 remarkably rapid drop in vitality in the course of the tenth 

 year^shown in kale, white turnip, and the two swedes. The 

 drop in the yellow turnip and rape is decidedly slower, begin- 

 ning somewhat earlier. It is interesting that five out of the 

 six cruciferous seeds lost their vitality in the same year ; the 

 one which failed earlier (rape) is one whose stai-ting point was 

 not so good, its original germinating power being only 85 

 per cent, as against IK} to 100 per cent, in the other five. 



The two plants not allied to the turnip, but included (for 

 convenience sake) in the same diagram, show a diff'erent curve : 

 while the crucifers maintain their vitality well for three to 

 five years, both carrot and yarrow lose as rapidly at the first as 

 they'do later. (Plate V.) 



