Introduction to the Angiosperms

Chapter 19

Angiosperms- Anthophyta• Autotrophic, but parasitic and

saprophytic representatives.• Enclosure of ovules within carpels.• Ovule- the structure in seed plants

that contains the female gametophyte with egg cell; including nucellus and integuments.

• Presence of endosperm in seeds.• Flower present with stamens

(microsporophylls) & carpels (megasporophylls).

• Species- 300,000-450,000

Class Monocotyledonae- monocots

• Flower parts- 3s.• Pollen- monoaperturate.• Cotyledons- 1.• Leaf venation- parallel.• 1° vascular bundles in

stem- complex.• 2° growth without vascular

cambium.• Examples- grasses, lilies, irises,

orchids, cattails, palms.

Class Eudicotyledonae- dicots

• Flower parts- 4s & 5s.• Pollen- triaperturate.• Cotyledons- 2.• Leaf venation- netlike.• 1° vascular bundles in

stem- ring.• 2° growth with

vascular cambium.• Examples- trees,

shrubs, herbs.

Ovary Position• Hypogynous- whorls attached below the ovary.• Perigynous- stamens and petals adnate to the calyx,

forming a tube (hypanthium) at the base of the ovary.• Epigynous- whorls attached above the ovary.

Epigyny in Malus (apple) flower

Mature Anther with 4 Microsporangia

Mature Embryo Sac- 8 nuclei, 7 celled structure

Double Fertilization

Endosperm- tissue that containsstored food that is digested by the sporophyte before or aftermaturation of the seed.