1) Bryophytes
a. Require water for fertilization
b. Lack vascular tissue
c. Lack true roots
d. Gametophyte is dominant generation
e. Reproduce asexually (ex. by gemmae cups in Marchantia)

· Mosses
· Liverworts
· Hornworts

Seedless vascular plants (sporophyte is dominant in all these plants)

2) Division Lycophyta
a. Lycopodium is homosporous (spores give rise to gametophytes bearing both archegonia and antheridia, which are female and male structures, respectively)
b. May have cones, which contain the sporangium-bearing leaves
c. Selaginella is heterosporous, meaning that two kinds of sporangia (megasporangia and microsporangia) are found in the same cone.

3) Division Psilotophyta
a. Psilotum—lacks both roots and leaves
b. homosporous

4) Division Spenophyta
a. Equisetum—horsetails; jointed stems and rough texture
b. homosporous

5) Division Pterophyta (ferns)
a. Sporangia occur in clusters called sori on the lower surface of a leaf (frond).
b. Gametophyte develops into a prothallus, from which antheridia and archegonia develop.

Gymnosperms (‘open-seed’)
6) Division Coniferophyta—needles are modified leaves
a. Separate male and female cones
b. Male gametophytes are the pollen grains.
c. Ovule encloses the female structure (egg).
d. Usually wind-dispersed.
7) Other gymnosperm divisions
a. Ginkophyta
b. Gnetophyta
c. Cycadophyta
 

Angiosperms—enclosed seed (flowering plants)

Division Anthophyta

Flower parts:
A) Outermost layer = sepals; collectively called the calyx.  Often these are small and green, but they may resemble petals in some cases.

B) 2nd layer in = petals; showy part of the flower; collectively called the corolla

Calyx and corolla together = perianth

C)  Next layer in = male portion of the flower = stamens; collectively called the androecium.  Stamens consist of an anther that contains pollen grains, and a filament, which is the stalk.

D)  Innermost part of a flower is the female portion = pistil (gynoecium); a pistil may be composed of one or more fused carpels (individual ‘compartments’).
· Stigma—receives pollen
· Style—stalk through which pollen tube grows
· Ovary—contains the ovules
 

Other terms:
1) Perfect flowers contain both male and female parts; imperfect flowers are lacking one or the other.
2) Complete flowers have all 4 parts described above; incomplete flowers may be lacking one of the components.
3) Staminate flowers are those with only male parts; pistillate or carpellate flowers have only female parts.
4) If a plant has both male and female flowers on the same plants, it is monoecious (one house); if a plant has male and female flowers on separate plants, it is dioecious (2 houses).
5) Clusters of flowers are called inflorescences.
6) The stalk of an inflorescence is called the peduncle, while the stalk of an individual flower is called the pedicel.
7) The flower stalk region to which flower parts are attached is called the receptacle.
 
 

Flower position is very important in classifying plants, and in determining how fruits are produced!

1) Superior ovary—ovary is above the sepals, petals and stamens
2) Inferior ovary—ovary is attached below the other floral parts

· Hypogynous flowers have superior ovaries; sepals, petals and stamens are attached but not fused.
· Perigynous flowers have superior ovaries, but the other floral parts are fused together to form a cup-shaped hypanthium
· Epigynous flowers have inferior ovaries; other floral parts are attached above the ovary.

Floral symmetry is also important in classifying plants.
1) Regular flowers—floral parts radiate from the center of the flower
2) Irregular flowers—bilaterally symmetrical (halves may mirror each other)
 

Angiosperm life cycle

· No antheridia or archegonia are found in flowering plants.
· Microgametophyte (male) consists of only 3 cells.
· Megagametophyte (female) has about 7-8 cells.

Microsporogenesis—formation of microspores (single-celled pollen grains) within pollen sacs.

· Initially, anther has uniform cells.  Four groups of fertile cells become visible.
· Nutritive cells called the tapetum make up the innermost layer of the wall.
· Microsporocytes (2n) develop from the sporogenous tissue.
· These divide meiotically and produce 4 haploid microspores (tetrad).
· Each microspore divides to form a tube cell and a generative cell—this is the immature pollen grain.
· The tube cell becomes the pollen tube, while the generative cell divides to produce 2 sperm.

· Pollen grains have two layers to their wall; the outer wall is called the exine, and the inner wall is called the intine.

Megasporogenesis—formation of several haploid nuclei, one of which is the egg.

· Within the ovule, one megasporocyte develops, and divides meiotically to form four haploid megaspores, three of which disintegrate.
· The remaining megaspore divides mitotically to produce 2, then 4, then 8 haploid nuclei; this is the mature female gametophyte.
· Of the 8 haploid nuclei, 5 disintegrate, and the remaining three fuse with sperm in the process known as double fertilization.

Double fertilization is unique to angiosperms!!

· The pollen tube enters the ovule through the micropyle (small opening).  It penetrates one of two cells surrounding the egg cell (synergids).  The synergids eventually break down, along with the 3 nuclei at the other end of the ovule (antipodals).
· One sperm fertilizes the egg cell.
· The other sperm fuses with the 2 nuclei in the center (polar nuclei), producing either 3n or 5n endosperm.
 

Embryo development
· Two-celled stage from division of zygote
· ‘Proembryo’ with a distinct suspensor
· Globular stage:  before cotyledons develop
· Heart stage—2-lobed form
· Torpedo stage—elongation of the axis and cotyledons
· Mature embryo—begin to see hypocotyl