Principals of Flowering Plants Taxonomy BOT 222 Dr. Najat Abdulwahab Bukhari Lecture 4

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Course Description Topics to be Covered Topic No of Weeks Contact hours - Historical review of plant taxonomy (industrial , natural, evolution) 1 2 - Nomenclature - Classic taxonomy (morphological taxonomy of vegetation and floral characters – Fruits and seed characters. 5 - Key to taxonomical unites. - Fertilization and seed formation - The different kinds of fruits - The sexual differentiations of flowers and their fertilization 14

Corolla

Corolla: consists of a number of the petals Corolla: consists of a number of the petals. The corolla extends from the calyx outwards., it is colored with bright colors to attract insects, birds, for the process of pollination and fertilization. Function: Attract insects to complete the process of pollination and fertilization. Protect the internal organs of the basic external influences.

Corolla can be as follows: Absent “Apetalous" as in Anemon. When the Corolla exist:’ The petals might be separated the plant is called “Polypetalous” as in the “Archichlamydeae” subfamily. Or the plant petals are combined the plant is called “Gamopetalus" , as in the “Metachlamydeae” subfamily.

Flowers of Dicotyledons number of petals is 5 and its multiples , and are called “Pentamerous” , sometimes its 4 and its multiples and is called “Tetra merous”. The petals has Limb and Claw . It is similar to the blade (Lamina) and Petiole of the leave. (Gamopetalous plants are more sophisticated than plants with separate flower petals).

In flowers of Monocotyledons plants number of floral leaves is 3 and its multiples , and called (trifoliate Tri merous). Exception to this rule Ranunculaceae . Corolla has a great importance in the process of classification and nomenclature many plant families, more important than the calyx form.

Corolla forms: When the petals are fused Gamopetalous): cruciate Corolla Which takes the form of the cross and consists of four petals arranged in a regular cross in two axes are orthogonal and, therefore, called cross

Rotate Corolla As tomatoes flowers , where the fused corolla widen directly from the basal lower and the upper part.

Funnel form Corolla The corolla tube enlarges gradually from below, it expands widely at the summit; infundibuliform

Pitcher-like “Urceslate Corolla “ : The Corolla takes the jar form, large below and contracted toward the mouth, as in the Erica (Ericaceae).

campanulate Corolla : The Corolla takes the form of bell where length and width of Corolla tube are the same. It has lobes, as in the Campanula.

When the petals separate "loose": Rose Form corolla

Papilio Form corolla

Toothed Petals edge Lobed Petals edge Lobed Petals edge

Lobed Petals edge Lobed Petals edge

Androecium

Androecium :The male reproductive organs of a flower considered as a group of stamens. When it consists of number of stamens it is called androecium, the number of stamens different on different flowers.

The stamens consists of : Filament: ( long or short stalk which carry an anther ,for the spread of pollen grains. It differs in shape depending on the method of pollination. Anther: (contains pollen grains) and consists of two locules, each locule contains a microsporangium Connective: the tissue between the locules.

Number of Stamens: Isostemonous : when number of stamens in consistent with the number of petals. Diplostemonous: when stamens are twice as many as petals. Haplostemonous: having stamens arranged in a single whorl or may be reduced with the extinction of the outer or inner whorl.

Position of Stamens: Diplostemonous: having twice as many stamens as petals, with the stamens arranged in two whorls

Obdiplostemonous: Having twice as many stamens as petals, those of the outer set being opposite the petals; - said of flowers. (Caryophyllaceae )

Emergence of Stamens: Stamens emerge of receptacle and in some cases out of the petals where they are fused with it and called in this case “Epipetalous" as in Wallflowers.

Length of Stamens: Stamens are either equal in length or differ, as in the where 4 stamens are same length and two shorter ones. The stamens in this case are called (Tetradynamous).

Didynamous, when two stamens are long and two short , as in (Scrophulariaceae )

stamens can be united in groups or separated depends on the plant’s kind. Filaments united: Monodelphous: Having stamen filaments united into a tube. As in Malva and Oxalix.

Diadelphous: Having the filaments of a flower united into two groups, as in beans and peas (Leguminosae family)

Polyadelphous: Having the filaments of a flower united so that they are arranged in three or more groups. As in Mallow, citrus fruits.

Anther fusion: 1. Anther tube Gynostegium as in (asclepiadaceae)

Stamen may be branching and the shape of the tree such as: Castor.

If stamens stopped function it is called "sterile" Staminods” as in Asalafia (Lamiaceae family) Some of the stamens may reduce to teeth.