` 262 Variation in Aistivation. [ May, 
quincuncial to the left. The other buds of that species were not 
observed. In the latter (A. cannabinum) four buds showed 
the sepals quincuncial to the left, and one to the right. 
It will be observed that the zstivation of Asclepias and Apoey- 
num are the same, at least so far as the specimens examined are 
concerned. 
In the Rubiaceæœ, of one hundred and fifty buds of Coph halan- 
thus I found that eighteen were convolute, thirteen to the right, 
three to the left. In Genera Plantarum of Bentham and Hooker, 
in the tribe containing this species the text says, “ Petals never 
contorted ” Keeping in mind the position of all the petals as 
they stand with reference to each other and to the axis, and no- 
ticing the direction of the spirals, I found the petals of thirty- 
seven buds arranged in twenty-three different modes. 
Each of the four petals was found to be outside, each inside, 
and each occupying either of the intermediate positions. 
If we disregard the direction of the spiral and the position of 
the axis, these twenty-three modes are reduced to six modes. 
In the same order, one hundred buds of Galium asprellum 
were all valvate. 
Malvacee: In four hundred and thirty-three buds of Mglva 
rotundifolia, two hundred and one petals were convolute to the 
right, two hundred and four to the left, fifteen quincuncial, and 
thirteen as in Figure 31. Lindley and Gray speak of the petals 
of this genus as convolute. 
Fig. 31. 
2 Š 
Tiliaceæ. In one hundred and seven buds of Tilia San 
fifty-nine were quincuncial, turning to the left, twenty-four to the 
right, thirteen as in Figure 32; eighi had one outside, and then 
the rest turned spirally to the right. Three were convolute to 
the left. 
Oxalis stricta. Of nineteen buds, ten had the sepals quincuń- 
cial to the right, nine to the left. In twelve of these buds the 
petals were convolute to the right, in five to the left, in one spi- 
rally to the right, in one a still different mode. 
In Serophularia nodosa, the — are imbricated in various 
