72 
PLANT MORPHOLOGY. 
in the violets ; revolute, when both margins are inrolled 
lengthwise on the lower surface, as in azalea. 
In addition, there are several terms used which are 
derived from the appearance of the bud, as reclinate 
or indexed, when the upper part is bent on the lower, 
as in Liriodendron ; and circinate, when the upper 
part is coiled on the lower, as in the ferns. 
B. REPRODUCTIVE PARTS OF THE PLANT. 
I. THE FLOWER. 
It is well known that if a portion of the stem of a 
plant, including one or more nodes, be placed under 
suitable conditions for growth, it will form roots and a 
new plant will be developed. This method of increas- 
ing the number of individuals is frequently resorted 
to by horticulturists, and is known as asexual repro- 
duction or propagation. It is fortunate, however, that 
owing to the special conditions required in this method 
of perpetuation and distribution of species, other meth- 
ods of reproduction are followed in nature, the most 
important of which depend upon the development of 
flowers and the production of seed. 
The flower may be looked upon as a modification of 
the stem and leaves to this end, and the continuing of 
the species by this means is known as true reproduction, 
or sexual reproduction. Considering the flower then 
as in the nature of a modified branch, it is seen that 
in both of these modes of reproduction the node, which 
together with the internode constitutes a phytomer, 
are essential. 
The nature and origin of the flower and its relation- 
ship to the branch are ordinarily not apparent, except 
in cases of reversion ; that is, where the parts of the 
flower assume the appearance of leaves or branches. 
