write the all description
Study family Liliaceae, prepare a table of following characteristics.
Character/Part
Description
Symmetry of flower
Bisexual/Unisexual
Calyx
Corolla
Androecium
Gynoecium
Aestivation
a. Calyx
b. Corolla
Placentation
Position of ovary
Type of fruit
Answers
Objective
Our objective is to study the characteristics of the following plants- Petunia, Lathyrus, Asparagus and Onion.
Theory
Let's begin with the basic anatomy of flowers.
Flower is a reproductive organ of the angiosperm plant that contains thalamus and floral leaves. A typical flower consists of four types of floral leaves called sepals, petals, stamens and carpels in distinct whorls normally known as calyx, corolla, androecium and gynoecium respectively. A flower in which all the four whorls are present (Sepal, Petal, Carpels, Stamens) are called as complete.The stalk of a flower is called as pedicel that holds the actual flower up in the air.
If a flower having both male and female sex organs are called bisexual and a flower having either only male or female organs is called unisexual. A flower having bract at its tip is called bracteate and without bracts is called ebracteate. A flower without a stalk or pedicel is called sessile and a flower having a stalk is called pedicellate. A flower may be trimerous, tetramerous or pentamerous when the floral leaves of each whorl are in multiple of 3, 4 or 5, respectively.
Based on the symmetry of the flowers can be described in to following types:
1. Actinomorphic: Flowers can be divided into two halves through any vertical plane.
2. Zygomorphic: Flowers can be divided into two equal halves only along one vertical plane.
3. Asymmetrical: Flowers which cannot be divided into equal halves by any plane.
Based on the position of calyx, corolla, and androecium with respect of ovary, the flowers are described as following:
1.Hypogynous (Superior ovary): Gynoecium occupies the highest position while the other parts are situated below it.
2.Perigynous (Half inferior): If gynoecium is situated in the centre and other parts of the flower are located on the rim of the thalamus almost at the same level.
3.Epigynous (Inferior ovary): The ovary situated in a flask shaped thalamus and other parts of flower arise above the ovary.
Parts of a flower
Each flower normally has four floral whorls, calyx, corolla, androecium and gynoecium.
1.Calyx
The calyx is the outermost whorl of the flower and is called sepals. Sepals looks like green leaves that are seen underneath the flower. Calyx may be gamosepalous (sepals united) or polysepalous (sepals free).
2.Corolla
The corolla is the second whorl of the flower and is composed of petals. Petals are the most colorful parts of a flower. Corolla may be gamopetalous (petals united) or polypetalous (petals free).
The arrangements of sepals or petals in the floral bud, with respect to the members of the same whorls are called aestivation.
1.Valvate: When sepals or petals do not overlap one another at the margin, without overlapping.
2.Twisted: Sepals or petals overlap with the next sepal or petal.
3. Imbricate: If the margins of sepals or petals overlap one another but not in any particular direction are called imbricate aestivation.
4.Vexillary: Among five petals, the largest petal (standard) overlaps the two lateral petals (wings) which in turn overlap two smallest anterior petals (Keel).
. Androecium
Androecium is the third whorl of the flower which contains the male reproductive organ, stamens. A stamen consists of an anther and a filament.
The stamens are variously fused among themselves. They can be of the following type:
Monoadelphous: stamens may be united into one bunch or one bundle. e.g., China rose
Diadelphous: stamens may be united into two bundles. e.g., pea
Polyadelphous: stamens may be united into more than two bundles. e.g., Citrus
Based on the attachment of filament to anther, it can be of the following type:
Basifixed: Filament of stamen is attached to base of the anther.
Adnate: Filament attached along the whole length of anther.
Dorsifixed: Filaments attached to the back of anther.
Versatile: Anther lobes attached with filament in the middle portion with both ends free
4.Gynoecium
Gynoecium is the innermost whorl of a flower, consisting of one or more units called carpels. Each carpel includes an ovary, a style and a stigma.
Carpels are of two types depending upon fusion:
Apocarpous: Carpels free from each other e.g., lotus
Syncarpous: Carpels fused with each other e.g., mustard.
The arrangement of placentae bearing ovules inside the ovary is called placentation. It is of following types.
Marginal: The placenta forms a ridge along the ventral suture of the ovary and the ovules are borne on this ridge e.g., pea.
Axile: Margins of carpels fuse to form central axis. e.g., tomato
Parietal: The ovules develop on the inner wall of the ovary. e.g., mustard.
Free central: Ovules borne from central axis and lacking septa. e.g., chilly.
Basal: Placenta develops at the base of the ovary. e.g., sunflower.
Answer:
Root:
It has adventitious roots and generally fibrous root system .
Stem :
Aerial or underground branched Rhizome in Gloriosa form in Colchicum , bulb in onion , scilla , aerial climbers in Gloriosa, Smilax .
Stem branches are modified into cladodes in Ruscus , Asparagus.
Inflorescence develop on special aerial stem called Sacpe.
Ex : Allium , Lilium
Leaves :
Mostly basal , alternate , linear exstipulate with parallel venation.
Type of fruit :
Capsule , rarely berries
Seed :
Endospermic
Flower :
Bracteate , ebracteolate , pedicillate , complete , bisexual or exceptionally unisexual as in Smilax and Ruscus ; actinomorphic , trimerous , hypogynous , homochlamydeous .
Perianth :
six sepals in two whorls , odd sepal of outer whorl in anterior in position ,and odd sepal of inner whorl is posterior in position.valvate aestivation.
Androecium :
Six stamens in two whorls (3+3) ,free or
epiphyllous , anthers ditecous , basifixed ,
introse with longitudinal dehiscence.
Gynoecium :
Tricarpellary , syncarpous ; superior ovary , trilocular with many ovules on axile placentation , style terminal , stigma trifid and capitate .
Pollination :
Flowers may be protandrous or protogynous entomophilous cross pollination.