THE 
AMERICAN NATURALIST. 
Vou. x1.— MAY, 1877. — No. 5. 
VARIATION IN ÆSTIVATION. 
BY PROF. W. J. wakes 
(THE great variety of ways in which the sepals and petals of 
each species meet or overlap each other in the bud is often 
quite wonderful. In some cases, after examining many flowers, 
this is found to be true, even in certain species which have been 
described by some of our best authors as having the parts con- 
stantly arranged in a certain definite manner. Take, for exam- 
ple, the diagrams found in Hooker’s Le Maout and Decaisne. It 
would seem as though the artist or the writers of the text, or both, 
had the idea that sepals and petals were arranged only in a few 
certain ways, as valvate, convolute, and imbricate in three modes, 
namely, spiral, opposite in twos, and quincuncial. It would ap- 
pear by their diagrams that they had been remarkably success- 
ful in finding no other forms, or that they had kept throwing 
away all others as accidental or spurious until those only were 
found and used which corresponded to their ideal. These re- 
ae will apply with equal force to several other botanical 
orks, ; ‘ 
In our best authors on botany, the diagrams showing the æs- 
tivation of the sepals of Crucifere all appear to be made as they 
look after the end of the flower-bud is cut off. This shows the 
Sepal next to the axis and the one opposite to it overlapping each 
edge of the two lateral sepals. There is nothing in such a dia- 
gram to indicate that the tip of the anterior sepal overlaps the 
tip of the posterior. This is the case in all the buds of the sev- 
eral species which I have examined. In the diagrams of all 
works accessible to me, there is nothing to show that the tip of - 
one of the side sepals overlaps the tip of the other. This over- 
lapping of one lateral sepal was found in all cases examined 
Where the tips were large enough for such purpose. ` Of fifteen 
buds of black mustard (Brassica nigra) examined, the sepals of 
ee RA or . 
Copyright, 1877, by A. S. Packarp, JR. 
