OK CHAKQES AND TARIATIONS IN CKOSS-FERTILIZED PEAS. 13 
size of the seeds produced are unaltered ; for I have on more than 
one occasion observed that the cot} ledons in the seeds directly- 
resulting from a cross of a blue wrinkled pea fertilized by the 
pollen of a white round variety have been of a greenish-white 
colour, and the seeds nearly round and larger or smaller accord- 
ingly as there may have been a difference in the size of the 
seeds of the two varieties. I have also noticed that a cross be- 
tween a round white and a blue wrinkled pea will in the third and 
fourth generations (second and third year's produce) at times 
bring forth blue round, blue wrinkled, white round, and white 
wrinkled peas in the same pod, that the white round seeds, when 
again sown, will produce only white round seeds, that the w^hite 
wrinkled seeds will, up to the fourth or fifth generation, produce 
both blue and white wrinkled and round peas, that the blue round 
peas will produce blue-wrinkled and round peas, but that the 
blue wrinkled peas will bear only blue wrinkled seeds. This 
would seem to indicate that the white round and the blue wrinkled 
peas are distinct varieties derived from ancestors respectively 
possessing one only of those marked qualities ; and, in my opinion, 
the white round peas trace their origin to a dwarfish pea having 
white flowers and round white seeds, and the blue wrinkled varie- 
ties to a tall variety having also white flowers but blue wrinkled 
seeds. 
It is also noticeable that from a single cross between two dif- 
ferent peas many hundreds of varieties, not only like one or both 
parents and intermediate, but apparently differing from either, 
may be produced in the course of three or four years (the shortest 
time which I have ascertained it takes to attain the climax of 
variation in the produce of cross-fertilized peas, and until which 
time it w^ould seem useless to expect a fixed seedling variety to be 
produced), although a reversion to the characters of either parent, 
or of any one of the ancestors, may take place at an earlier 
period. These circumstances do not appear to have been known 
to Mr. Knight, as he seems to have carried on his experiments by 
continuing to cross his seedlings in the year succeeding their pro- 
duction from a cross and treating the results as reliable ; whereas 
it is probable that the results might have been materially affected 
by the disturbing causes then in existence arising from the pre- 
vious cross fertilization, and which, I consider, would, in all cases 
where either parent has not become fixed or permanent, lead to 
results positively perplexing and uncertain, and to variations 
