Morphology of Flowering Plants

Monocotyledonous plants

Monocotyledonous plants

plants which have a fibrous root system

Dicotyledonous plants

plants which have a tap root system i.e. primary, secondary, and tertiary, etc. roots

Adventitious roots

the roots that arise from any part of the plant other than the radicle

rootcap

protects the tender apex of the root

Meristematic region

just above the rootcap and extends to a few mm above; consists to rapidly dividing meristematic tissues

Region of elongation

region above the meristematic region; the meristematic cells stop diving and start elongating; responsible for lengthening of root

Region of maturation

region above the region of elongation; cells stop growing and elongating, becomes a mature plant cell; root hair arises in this region from the epidermal cells

Perennation

The ability of an organism to survive from one germinating season to the next, especially under unfavorable conditions such as drought or winter.

Axillary bud

each leaf possesses a bud in its axil which is known as the axillary bud.

petiole

stalk of the leaf

lamina

green expanded part of the leaf; main area of photosynthesis; supported by veins and veinlets

Midrib

The middle prominent vein on a lamina

Veins

provide rigidity and support; are the channels of transport of water, minerals, and food material

Venation

arrangement of veins and veinlets in the leaf

Reticulate venation

when the midrib and its branches make a network (reticulum) on the lamina; characteristic property of dicot plants

Parallel venation

when the veins on the lamina run parallel to each other; characteristic property of monocot plants

Simple leaf

when its lamina is entire OR when incised, the incisions do not run down to the midrib; mango

Compound leaf

when its lamina is incised down to the midrib into a number of segments called leaflets, each with a very short stalk; a leaf HAS a bud in its axil, however, a leaflet DOES NOT have a bud in its axil

Pinnately Compound leaf

leaflets are arranged along the length of the rachis (represents the midrib); neem, rose

Palmately Compound leaf

leaflets arise from a common point i.e. the tip of the rachis/petiole; silk cotton

Phyllotaxy

mode of arrangement of leaves on the stem/branch; may be alternate, opposite, or whorled

Inflorescence

the manner in which the flowers are arranged on the flowering axis

Pedicel

stalk of the flower

Thalamus/Torus

the swollen end of the pedicel on which the floral leaves are arranged in whorls

Bisexual/Hermaphrodite flower

flower with both androecium and gynoecium

Unisexual flower

flower that has either only androecium (male) or only gynoecium (female)

Asymmetric (irregular) flower

the flower cannot be divided into two similar halves along any vertical plane passing through the centre; canna

Trimerous, Tetramerous, or Pentamerous flowers

if the flower has multiples of 3, 4, or 5 appendages

Bract

a modified leaf or scale, typically small, with a flower or flower cluster in its axil. Bracts are sometimes larger and more brightly colored than the true flower.

Bracteate flower

flowers with bracts-reduced leaf found at the base of the pedicel

Ebracteate flower

flowers without bracts

Hypogynous flower

gynoecium occupies highest position while the other parts are situated below it

ovary is said to be superior

Perigynous flower

gynoecium is situated in the center and other parts of the flower are located on the rim of the thalamus at almost the same level

ovary is said to be half inferior

Epigynous flower

the margin of thalamus grows upwards, enclosing the ovary completely and getting fused with it

other parts of the flower arise above the ovary

ovary is said to be inferior

Calyx

outermost whorl aka sepals

generally, sepals are green, leaf like structures that protect the flower bud

Gamosepalous flower

The sepals of the flower are united/fused

Polysepalous flower

The sepals of the flower are free

Corolla

the whorl which is composed of the petals

brightly colored to attract pollinators

Gamopetalous flower

petals are united/fused

Polypetalous flower

petals are free

Aestivation

Mode of arrangement of sepals or petals in floral bud wrt the other members of the same whorl

Types of aestivation

i) valvate- sepals/petals just touch one another at the margin w/o overlapping

ii) twisted- one margin of the appendage overlaps that of the next one

iii) imbricate- if margins of sepals/petals overlap one another but not in any particular direction

iv) vexillary- five petals where the largest (standard) overlaps two lateral petals (wings) which in turn overlap the two smallest anterior petals (keel). aka papilionaceous

staminode

sterile stamen

Epipetalous flower

stamens are attached to the petals

Epiphyllous flower

stamens are attached to the perianth

perianth

the outer whorls of the flower - calyx and corolla

Polyandrous flower

stamens are fused/united

Monoadelphous flower

stamens are united in one bunch/bundle

Diadelphous flower

stamens are united in two bunches/bundles

Polyadelphous flower

stamens are united into more than two bunches

Placenta

flattened cushion-like structure to which the ovules are attached in the ovary

Apocarpous flower

more than one carpels are present and theyre free

Syncarpous flower

more than one carpels are present and theyre fused/united

Placentation

arrangement of ovules within the ovary

Types of placentation

i) marginal- placenta forms a ridge ovules are borne on the ridge in two rows

ii) axile- placenta is axial and ovules are attached to it in a multilocular ovary

iii) parietal- ovules develop on the inner wall of the ovary or peripheral part

iv) free central- ovules are borne on central axis and septa are absent

v) basal- placenta develops at the base of ovary and a single ovule is attached to it

Parthenocarpic fruit

fruit is formed without fertilisation of the ovary

Pericarp

wall of the fruit

may be dry or fleshy

can be differentiated into epicarp(outer), mesocarp(middle), and endocarp(inner)