Morphology of Flowering Plants

It is also a type of twisted aestivation. In this type the perianth lobes overlap in such a manner that the margins of the two perianth lobes are completely inside, and the other two perianth lobes are outside, and in the remaining one perianth lobe, one margin is inside an the other margin is outside. Example: calyx of Ipomoea & Catharanthus.

Chemo-tropism is the growth of organisms  such as bacteria and plants, navigated by chemical stimulus from outside of the organism or organisms part. An example of chemo-tropic movement can be seen during the growth of the pollen tube, where growth is always towards the ovules. The conversion of flower into fruit is also an example of chemo-tropism.

Proteoid roots form the clusters of closely spaced short lateral rootlets. They may form a two to five centimetre thick mat just beneath the leaf litter. They enhance nutrient uptake, possibly by chemically modifying the soil environment to improve nutrient solubilisation.

An oblong leaf has parallel sides. The leaf has a rectangular shape with rounded corners. An example of this kind of leaf is willow.

Secondary dormancy occurs in some non-dormant and post dormant seeds that are exposed to conditions that are not favourable for germination, like high temperatures. It is caused by conditions that occur after the seeds have been dispersed.

It is a simple fleshy, false fruit. It develops from a syncarpous inferior ovary having axile placentation. After fertilization, the thalamus becomes fleshy and edible. But the actual fruit lies within, e.g. apple.

At the third stage, the outer layer of cells divide so that the primordium is now made of three layers.

In basal placentation, the placenta develops at the base of ovary and a single ovule is attached to it, as in sunflower, marigold, etc.

A cleistogamous flower is usually smaller and requires less energy to produce. It is also structured to bring its reproductive organs into contact, making it more likely that fertilization will be successful.

It is a simple, dry, dehiscent fruit developing from the bicarpellary, monolocular ovary having two parietal placentae. The ovary is monolocular in the beginning, but becomes bilocular due to the development of a false septum called replum. The pericarp dehisces into two halves from below upwards. The seeds remain attached to the central replum, e.g. mustard, radish, etc.

In plants such as wheat, rice, gram and mustard the plants die after seed production. This is also observed in monocarpic plants which live for several years but flower only once in their life time as in sago palm and bamboos.

In determinate inflorescence the terminal axis is with a flower. In this type of inflorescence the youngest flowers are found on the bottom of an elongated axis or on the outside of a truncated axis. e.g. onions

Non-recurrent apomixis is where an embryo arises directly from a normal egg-cell without the process of fertilization. Egg cells are haploid and hence, the resulting embryo is also haploid. It includes haploid parthenogenesis, haploid apogamy and adrogamy.

Some plants are self-sterile, i.e. they are not fertilised when pollinated by the same variety of plant. In order to produce fruits, these plants require pollen from plants of a different genetic makeup. Some examples of self-incompatible plants are pineapples, navel oranges, and clementines.

Barochory or the plant use of gravity for dispersal is a simple means of achieving seed dispersal. The effect of gravity on heavier fruits causes them to fall from the plant when ripe. Fruits exhibiting this type of dispersal include apples, coconuts and passion fruit, and those with harder shells.