CHAPTER
5 Plant Kingdom
Classification Systems Bryophytes
Artificial Classification System: Commonly called as amphibians of plant kingdom.
Given by Carolus Linnaeus. Includes Liverworts and mosses.
Based mainly on vegetative characters or on the androecium Vascular tissues are absent.
structure
Lack true stem, leaves and roots.
Separated the closely related species since they were based
on a few characteristics. Main plant body is gametophyte. Sporophyte is dependent
Gave equal weightage to vegetative and sexual characteristics. on gametophyte for nutrition.
Natural Classification System: Plant body attached to substratum by unicellular or
Given by George Bentham and Joseph Dalton Hooker.
multicellular rhizoids.
Based on natural affinities among the organisms. Water is essential for fertilization.
Consider both external and internal features. Sex organs are multicellular. Male-antheridium and
Phylogenetic Classification System: female-archegonium.
Based on evolutionary relationships between the various Fertilization produces zygote which develops into
organisms. multicellular sporophyte.
Assumes that organisms belonging to the same taxa have a
common ancestor. Liverworts
Grow usually in moist and shady habitats.
Numerical Taxonomy
Carried out using computers and based on all observable
Plant body is thalloid which is dorsiventral and closely
characteristics. appressed to the substrate.
Each character is given equal importance and at the same Leafy members have tiny leaf-like appendages in two rows
time hundreds of characters can be considered. on the stem-like structures.
Cytotaxonomy Asexual reproduction through fragmentation.
Based on cytological information like chromosome number, Gemmae are green, multicellular asexual buds.
structure, behaviour.
Sporophyte is formed as a result of sexual reproduction.
Chemotaxonomy Sporophyte is differentiated into foot, seta and capsule.
Uses the chemical constituents of the plant to resolve confusions.
After meiosis, spores are produced within the capsule which
Classification of Algae germinate to form free-living gametophytes. E.g., Marchantia
Features Chlorophyceae Phaeophyceae Rhodophyceae Mosses
Common Green algae Brown algae Red algae
Protonema is the first stage of gametophyte that develops
name
directly from spore.
Pigment Chl a, b Chl a, c and Chl a, d and
fucoxanthin r-phycoerythrin Leafy stage is second stage develops from secondary
protonema as lateral bud.
Reserve Starch Laminarin, Floridean
food Mannitol starch Vegetative reproduction through fragmentation and budding
Flagella 2-8, equal, apical 2, unequal, Absent in secondary protonema.
lateral Sexual reproduction present.
Examples Chlamydomonas, Ectocarpus, Polysiphonia, Have an elaborate mechanism of spore dispersal. E.g.,
Volvox etc. Sargassum etc. Gracilaria etc. Funaria, Polytrichum and Sphagnum.
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5 Plant Kingdom
Classification Systems Bryophytes
Artificial Classification System: Commonly called as amphibians of plant kingdom.
Given by Carolus Linnaeus. Includes Liverworts and mosses.
Based mainly on vegetative characters or on the androecium Vascular tissues are absent.
structure
Lack true stem, leaves and roots.
Separated the closely related species since they were based
on a few characteristics. Main plant body is gametophyte. Sporophyte is dependent
Gave equal weightage to vegetative and sexual characteristics. on gametophyte for nutrition.
Natural Classification System: Plant body attached to substratum by unicellular or
Given by George Bentham and Joseph Dalton Hooker.
multicellular rhizoids.
Based on natural affinities among the organisms. Water is essential for fertilization.
Consider both external and internal features. Sex organs are multicellular. Male-antheridium and
Phylogenetic Classification System: female-archegonium.
Based on evolutionary relationships between the various Fertilization produces zygote which develops into
organisms. multicellular sporophyte.
Assumes that organisms belonging to the same taxa have a
common ancestor. Liverworts
Grow usually in moist and shady habitats.
Numerical Taxonomy
Carried out using computers and based on all observable
Plant body is thalloid which is dorsiventral and closely
characteristics. appressed to the substrate.
Each character is given equal importance and at the same Leafy members have tiny leaf-like appendages in two rows
time hundreds of characters can be considered. on the stem-like structures.
Cytotaxonomy Asexual reproduction through fragmentation.
Based on cytological information like chromosome number, Gemmae are green, multicellular asexual buds.
structure, behaviour.
Sporophyte is formed as a result of sexual reproduction.
Chemotaxonomy Sporophyte is differentiated into foot, seta and capsule.
Uses the chemical constituents of the plant to resolve confusions.
After meiosis, spores are produced within the capsule which
Classification of Algae germinate to form free-living gametophytes. E.g., Marchantia
Features Chlorophyceae Phaeophyceae Rhodophyceae Mosses
Common Green algae Brown algae Red algae
Protonema is the first stage of gametophyte that develops
name
directly from spore.
Pigment Chl a, b Chl a, c and Chl a, d and
fucoxanthin r-phycoerythrin Leafy stage is second stage develops from secondary
protonema as lateral bud.
Reserve Starch Laminarin, Floridean
food Mannitol starch Vegetative reproduction through fragmentation and budding
Flagella 2-8, equal, apical 2, unequal, Absent in secondary protonema.
lateral Sexual reproduction present.
Examples Chlamydomonas, Ectocarpus, Polysiphonia, Have an elaborate mechanism of spore dispersal. E.g.,
Volvox etc. Sargassum etc. Gracilaria etc. Funaria, Polytrichum and Sphagnum.
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W Plant Kingdom 9
