49 
‘a fixed numeric law, 4 so arranged as to pisael oceupy all the 
positions aaa MEN Mthe ambit and but once within the set; 
Eig viz, a the sense > of the oe cova fibre or split) takes 
place, is a cycle. 
n a bird's-eye view, the ambit-is by the leaves di ivided into as 
many interstices as there are leaves toa cycle. Then umber of 
leaves, or interstices, in a given cycle, is called the ‘ ‘eylar nume= 
ber” thereof, 
The Se either occur, as they most frequents do, in divi 
file succession, after a certain law of alternation hak, 
cle (e. g., of 8 Lasek ope ta 8 different positions), of owes 
when continued after the same plan, the 9th is found superincum- 
bent or correspondent to the rs cones umed one; or, a number of 
leaves are placed at equal heights, paiosing like the spokes of a 
wheel, gary disposition is called a whorl or vertical, and either 
com cycle, or, as is mostly the stil number “of alternate 
whorls are sequtred before the subsequent one becomes duly su- 
perincumbent above the first assumed one. 
In each of these chses, the number in question—whether of 
singly disposed leaves to a cycle, or the oe of leaves compos- 
ing a whorl, or rai whorls completing a sane: gp nd) cycle—is al- 
ways, with few exceptions, one of these, and no others: 1, 2, 3, 
5, 8,13, as 31, 55, 89, 144, 933, 377, etc. A series evolved 
by a le of siding te oie numbers on hand, 
org tis hs 1, a Fa y Aa Les Gi3\at, (513) 
==8, Sada id, © te.; and ote ake jivergence, or of 
7 raphic) interstices Contin in 
