Branching Patterns of Stem
- The unbranched stem is called caudex or columnar, e.g., palm, sugarcane, maize.
- Branching in stem may be of two types:
The growing point gets divided into two in the
region of branching,e.g., Dictyota(alga),
The growing point does not
get divided. Racemose
The terminal bud continues its
activity indefinitely.The lateral
branches are borne over it in an
acropetal succession,e.g., Pinus,
The terminal bud, after forming a
small portion of the axis, either
stops its activity or gets modified
into a flower, tendril, thorn, etc.
It is of three types.
Further growth of the stem is
continued by a single axillary branch.
The main axis is formed by the
fusion of bases of axillary branches
and the main stem. It is called
sympodial axis (sympodium)
7 6 5 4 3 2 1
Further growth is continued by
two axillary branches, the process
is repeated and the axis is
4 2 2
Further growth is continued by a
whorl of three of more axillary
branches.The axis is multipodial,
e.g., Euphorbia helioscopia.
- Stem grows by means of a terminal bud which represents a condensed immature or embryonic shoot possessing a growing
point. The buds are generally small in size. The largest bud is that of cabbage. According to their nature/structure, buds can
be vegetative (form leafy shoots only), floral (reproductive buds that develop into flowers) or mixed (both vegetative
and floral branches).
On the basis of
On the basis of
Buds may become dormant for short or
long periods. They are usually covered
by protective scales having hair, waxy
coating or resin, e.g., Ficus, Calotropis.
Some buds become active as soon
as they are formed. They are usually
Grow from position other than normal
Borne at apex
Borne other than apices
Arises in axil
of leaf, e.g.,
Arises on side or
above axillary bud,
Arises on node, e.g.,
Arises on leaves, e.g.,
Arises on stem,
Arises on roots, e.g.,
Types of Bud
Diverse Forms of Stem
- Stem may be aerial, sub-aerial or underground. These are variously modified to perform different functions such as storage
of food, vegetative propagation, mechanical support, protection, etc.
- Aerial stems are usually upright and may be erect or weak.