Jal Relea IMBRICATIVE ASTIVATION. 
immaterial in diagram. When the inflorescence is indefinite, how- 
ever, the external petal sometimes maintains a fixed relation to 
the axis. For instance, in papilionaceous flowers, the external 
petal is always the posterior one. In the violet the external petal 
may be either the right or left upper petal, the lower spurred petal 
being always internal. In many plants on the contrary, some of 
the flowers commence the spiral at one part of the whorl, and 
other flowers at other parts of the whorl. This is shown by the 
example of Pyrola elliptica (Table II.) 
11. For the purpose of observing and recording the mode of 
imbrication in a pentamerous flower for example, rule a table as 
follows (Table I): 
n the Table, I denotes the first case or regular imbrication; I 
denotes the second case or irregular imbrication ; while 1 and 2 
indicate the first and second variety of II. Each example 1$ 
marked by the direction of the spiral. Summing up the observa- 
tions of 100 flowers of Rubus odoratus, examined for the illustra- 
tion of this article, they show the following variety of arrange- 
ment : 
Calyx, imbricate. 
Case I. + 54, —46. Total, 100. 
Corolla, imbricate. 
Case I. + 22,—10. Total, 32. 
Case IT. 
1y.+14,—13. Total, 27. 
2v.+20,—13. Total, 33. 
Corolla, contorted, 
+4,— 4. Total, 8. 
Total + 60, — 40. 
Fe E E Se ee lg Sn rs a fe 39 fg Soe 
