Morphology Of Flowering Plants

In cymose inflorescence, the main axis ends in a flower and similarly the lateral axis also ends in a flower. Thus the growth of each axis is checked. In cymose inflorescence, the terminal flower is always older and opens earlier than the lateral ones, i.e., the order of opening of flowers is centrifugal.

In racemose head, the main axis or receptacle is suppressed, becoming almost flat. It bears a mass of small sessile flowers (florets) on its surface, with one or more whorls of bracts at the base forming an involucre. The florets are arranged in a centripetal fashion, i.e., younger towards the centre and older towards the periphery. The advantages of this kind of inflorescence are that the head as a whole becomes more showy and attractive and the florets being close together, one or a few insects can pollinate most of them within a short time.

Root hair zone is 1-6 cm in length. The root hairs increase the exposed surface of the root for absorption of water and minerals.

Cymose inflorescence is the name of determinate or definite inflorescence in which the tip of the main axis terminates in a flower and further growth continues by one more lateral branches which also behave like the main axis.
Verticillaster is a special form of cymose inflorescence. The first axis ends in a flower, it bears two lateral branches, each ending in a flower, succeeding lateral branches are produced in an alternating manner.

A leaf having a single or undivided lamina is called simple leaf. The lamina can have different types of incisions, which may reach upto half (-fid), more than half (-partite) or near the base or midrib (-sect). Depending upon the pinnate or palmate venation, the incisions are known as pinnatifid palmatifid, pinnatipartite,palmatipartite,pinnatisectand palmatisect.

In cymose branching the growth of the main stem is definite, that is the terminal bud does not continue to grow, but lower down, the main stem produces one or more lateral branches which grow more vigorously than the terminal one. In some plants the terminal bud gets modified into a flower, tendril, thorn etc.

In spiral arrangement, each node bears a leaf and the leaves of the adjacent nodes roughly lie towards the opposite sides. In opposite arrangement, two leaves are borne on the opposite sides of a single node. When three or more leaves develop on the nodes, they form whorled arrangement.

The pericarp of drupe is differentiated into epicarp, mesocarp and endocarp. Endocarp is stony. Hence drupes are also called stone fruits. Coconut called fibrous drupe due to fibrous mesocarp, possesses edible endosperm. Among drupes, the mango has edible mesocarp, cherry, peach, plum and Zizyphus have edible epicarp and mesocarp.