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PLANTAE
Chapter 38
Characteristics of Plants
 multicellular
eukaryotes
 cell walls contain cellulose
 starch is carbohydrate reserve
 most are photoautotrophic
 cells contain chloroplasts
 most are terrestrial
 have alternation of generations
sporophyte
- diploid (2n) stage
gametophyte - haploid (n) stage
Plant Life Cycle
Evidence indicates that aquatic plants
evolved from freshwater green algae
(charophytes) ~ 476 million years ago.
Adaptations to life on land:
 conspicuous sporophyte that
protects gametophyte & zygote
 vascular tissue
 root systems
 lignin
 waterproof cuticle & stomata
A. Bryophytes
 small
green plants
 lack vascular tissue, supportive tissue,
true leaves & stems
 possess lignin
 have rhizoids
 asexual reproduction predominates
 gametophyte is most conspicuous stage
 sporophyte is attached to & dependent
on gametophyte
Bryophytes include the liverworts,
hornworts & mosses.
1. Liverworts
(division
Hepaticophyta)
2. Hornworts
(division
Anthocerotophyta)
3. Mosses
(division
Bryophyta)
B. Seedless Vascular Plants
 contain
vascular tissue
 have well developed cuticle & stomata
 sporophyte
is most
conspicuous
stage
Seedless vascular plants include the club
mosses, whisk ferns, horsetails & true
ferns.
1. Club mosses
(division
Lycophyta)
 have leaves,
stems & roots
2. Horsetails
(division
Sphenophyta)
 epidermis
contains silica
3. Whisk ferns
(division
Psilophyta)
 lack roots
 most lack leaves
4. True ferns
(division
Pterophyta)
 fronds
seasonally
produce sori
C. Seed-Producing Vascular Plants
Origin of seeds (~ 360 million years ago)
enhanced plant survival on dry land.
Two major groups:
 Gymnosperms (naked seed plants)
 Angiosperms (flowering plants)
1. Gymnosperms
Most are wind pollinated.
 Cycads (division Cycadophyta)
 have
palm-like leaves
 separate  and  plants
  produces large cones
 Ginkgo (division Ginkgophyta)
 have
fan-shaped leaves
 separate
 and  plants
produces foul smelling
seeds

 Conifers (division Coniferophyta)
 have
needle-like or scale-like leaves
 include pine, fir, larch, spruce,
juniper & coastal redwood
 Gnetophytes (division Gnetophyta)
 most
closely related to flowering
plants
 include Ephedra, which contains
ephedrine (decongestant that also
stimulates the nervous system)
2. Angiosperms (division Anthophyta or
Magnoliophyta)
 arose
about 200 million years ago
 produce flowers
 most are pollinated by insects & other
animals
 seeds are enclosed in fruits (protect
seeds & aid in dispersal)
Two major classes:
 Monocotyledons (monocots)
 Dicotyledons (dicots)
Cattails (monocot)
Red Passion Vine
(dicot)