The seeds after germinating on sand were planted in pairs on the opposite sides of four pots, with all the remaining seeds sown crowded in the opposite sides of a fifth pot; in this latter pot only the tallest plant on each side was measured.  Until the seedlings had grown about 5 inches in height no difference could be perceived in the two lots.  Both lots flowered at nearly the same time.  When they had almost done flowering, the tallest flower-stem on each plant was measured, as shown in Table 4/45.

Table 4/45.  Viscaria oculata.

Tallest flower-stem on each plant measured in inches.

Column 1:  Number (Name) of Pot.

Column 2:  Crossed Plants.

Column 3:  Self-fertilised Plants.

Pot 1 :  19 :  32 3/8. 
Pot 1 :  33 :  38. 
Pot 1 :  41 :  38. 
Pot 1 :  41 :  28 7/8.

Pot 2 :  37 4/8 :  36. 
Pot 2 :  36 4/8 :  32 3/8. 
Pot 2 :  38 :  35 6/8.

Pot 3 :  44 4/8 :  36. 
Pot 3 :  39 4/8 :  20 7/8. 
Pot 3 :  39 :  30 5/8.

Pot 4 :  30 2/8 :  36. 
Pot 4 :  31 :  39. 
Pot 4 :  33 1/8 :  29. 
Pot 4 :  24 :  38 4/8.

Pot 5 :  30 2/8 :  32. 
Crowded.

Total :  517.63 :  503.36.

The fifteen crossed plants here average 34.5, and the fifteen self-fertilised 33.55 inches in height; or as 100 to 97.  So that the excess of height of the crossed plants is quite insignificant.  In productiveness, however, the difference was much more plainly marked.  All the capsules were gathered from both lots of plants (except from the crowded and unproductive ones in Pot 5), and at the close of the season the few remaining flowers were added in.  The fourteen crossed plants produced 381, whilst the fourteen self-fertilised plants produced only 293 capsules and flowers; or as 100 to 77.

Dianthus caryophyllus.

The common carnation is strongly proterandrous, and therefore depends to a large extent upon insects for fertilisation.  I have seen only humble-bees visiting the flowers, but I dare say other insects likewise do so.  It is notorious that if pure seed is desired, the greatest care is necessary to prevent the varieties which grow in the same garden from intercrossing. (4/10.  ‘Gardeners’ Chronicle’ 1847 page 268.) The pollen is generally shed and lost before the two stigmas in the same flower diverge and are ready to be fertilised.  I was therefore often forced to use for self-fertilisation pollen from the same plant instead of from the same flower.  But on two occasions, when I attended to this point, I was not able to detect any marked difference in the number of seeds produced by these two forms of self-fertilisation.