Plant Kingdom – Key Vocabulary

A comprehensive set of vocabulary flashcards covering major concepts, groups, structures and terms introduced in the Plant Kingdom lecture.

Five-Kingdom Classification

Whittaker’s (1969) system dividing life into Monera, Protista, Fungi, Animalia and Plantae.

Plantae

The kingdom comprising multicellular, primarily photosynthetic organisms such as algae, bryophytes, pteridophytes, gymnosperms and angiosperms.

Artificial Classification System

Early plant grouping based on superficial, mainly vegetative characters (e.g., Linnaeus’ system).

Natural Classification System

System that groups plants using many external and internal features to reflect natural affinities (Bentham & Hooker).

Phylogenetic Classification System

Modern approach arranging plants according to their evolutionary relationships and common ancestry.

Numerical Taxonomy

Computer-aided classification that assigns equal weight to numerous coded characters.

Cytotaxonomy

Classification that employs chromosome number, structure and behaviour.

Chemotaxonomy

Use of plant chemical constituents to clarify taxonomic relationships.

Algae

Chlorophyll-bearing, thalloid, autotrophic organisms, mostly aquatic; primary producers in aquatic food chains.

Bryophytes

Amphibious land plants (mosses, liverworts) whose gametophyte is dominant and water is needed for fertilisation.

Pteridophytes

Vascular, spore-bearing plants (ferns, horsetails) with dominant sporophyte possessing true roots, stems and leaves.

Gymnosperms

Seed plants with naked ovules and seeds, commonly forming cones (e.g., Pinus, Cycas).

Angiosperms

Flowering plants whose ovules are enclosed in ovaries and seeds within fruits.

Chlorophyceae

Green algae class rich in chlorophyll a & b; stores starch in pyrenoids (e.g., Chlamydomonas, Spirogyra).

Phaeophyceae

Brown algae class possessing chlorophyll a, c and fucoxanthin; stores laminarin or mannitol (e.g., Laminaria).

Rhodophyceae

Red algae class dominated by r-phycoerythrin pigment; stores floridean starch (e.g., Polysiphonia).

Isogamy

Sexual reproduction involving fusion of morphologically similar gametes.

Anisogamy

Fusion of gametes differing in size or form but both motile (e.g., Eudorina).

Oogamy

Fusion between a large non-motile egg and a smaller motile sperm (e.g., Volvox).

Zoospore

Flagellated, asexual, motile spore common in algae for dispersal and propagation.

Pyrenoid

Protein–starch storage structure within chloroplasts of many green algae.

Gametophyte

Haploid, gamete-producing generation in plant life cycles (dominant in bryophytes).

Sporophyte

Diploid, spore-producing generation; dominant in pteridophytes, gymnosperms and angiosperms.

Antheridium

Multicellular male sex organ producing antherozoids in bryophytes and pteridophytes.

Archegonium

Flask-shaped female sex organ enclosing a single egg in bryophytes, pteridophytes and gymnosperms.

Liverworts

Group of bryophytes with dorsiventral thallus; reproduce via gemmae (e.g., Marchantia).

Mosses

Bryophytes with leafy gametophytes; life cycle includes protonema and leafy stages (e.g., Funaria).

Protonema

First, filamentous gametophytic stage emerging from a moss spore.

Gemmae

Multicellular asexual buds formed in gemma cups of liverworts for vegetative reproduction.

Peat

Partially decomposed Sphagnum moss accumulation used as fuel and packing material.

Sporophyll

Leaf-like structure bearing sporangia in pteridophytes and gymnosperms.

Strobilus

Cone-like aggregation of sporophylls (e.g., Selaginella, Pinus).

Prothallus

Small, green, thalloid gametophyte of pteridophytes arising from a spore.

Homosporous

Producing one kind of spore (e.g., most ferns).

Heterosporous

Producing two distinct spores: microspores and megaspores (e.g., Selaginella, Salvinia).

Seed Habit

Retention and protection of the female gametophyte and developing embryo on the parent plant; foreshadowed in heterosporous pteridophytes.

Mycorrhiza

Mutualistic association between a plant root and a fungus, common in Pinus roots.

Coralloid Roots

Cyanobacteria-harbouring, dichotomously branched roots of Cycas specialized for nitrogen fixation.

Pollen Grain

Highly reduced male gametophyte of seed plants formed within microsporangia.

Ovule

Megasporangium enclosed by integuments; develops into a seed after fertilisation.

Naked Seed

Seed not enclosed in fruit; characteristic of gymnosperms.

Dicotyledon

Angiosperm class whose embryos possess two cotyledons (e.g., beans, oak).

Monocotyledon

Angiosperm class with a single embryonic cotyledon (e.g., grasses, lilies).

Holdfast

Basal attachment structure anchoring many algae to a substrate.

Fucoxanthin

Brown xanthophyll pigment giving phaeophyceae their characteristic colour.

Floridean Starch

Reserve carbohydrate found in red algae, similar to glycogen in structure.

Laminarin

Storage polysaccharide of brown algae.

Mannitol

Sugar alcohol serving as reserve food in brown algae.

Algin

Commercial hydrocolloid extracted from brown algae for thickening/gel-forming uses.

Carrageen

Sulfated polysaccharide from red algae used in food and pharmaceuticals as a gelling agent.

Agar

Gel-forming substance from Gelidium and Gracilaria employed as microbial culture medium and in desserts.

Chlorella

Protein-rich unicellular green alga used as food supplement, even for space travellers.