Plant Kingdom – Key Vocabulary

Vocabulary flashcards covering principal terms and concepts from the Plant Kingdom lecture.

Artificial classification system

An early plant‐classification approach that grouped species using only a few easily observed external or vegetative characters, giving all traits equal weight and often separating closely related taxa.

Natural classification system

A system that arranges plants according to overall natural affinities, employing both external and internal features such as anatomy, embryology and chemistry.

Phylogenetic classification system

A modern scheme that orders organisms by evolutionary relationships and common ancestry, frequently supported by fossil, molecular and other data.

Numerical taxonomy

Computer-assisted classification that assigns numbers to many observable traits so each character receives equal importance when clustering organisms.

Cytotaxonomy

The use of cytological data—chromosome number, structure and behaviour—for solving taxonomic questions.

Chemotaxonomy

Classification based on the chemical constituents (e.g., secondary metabolites) present in plants.

Chlorophyceae

The green‐algae class containing chlorophyll a & b, cellulose walls and starch/pyrenoid storage; includes Chlamydomonas, Volvox, Ulothrix.

Phaeophyceae

The brown‐algae class, mostly marine, with pigments chlorophyll a, c and fucoxanthin; stores mannitol or laminarin; includes kelps such as Laminaria.

Rhodophyceae

The red‐algae class rich in r-phycoerythrin, mainly marine, storing floridean starch; examples are Porphyra and Polysiphonia.

Isogamous reproduction

Sexual reproduction involving fusion of morphologically similar gametes, which may be either motile or non-motile.

Anisogamous reproduction

Fusion of two dissimilar gametes, typically differing in size although both may be motile.

Oogamous reproduction

Sexual process in which a large non-motile female gamete (egg) fuses with a smaller motile male gamete.

Pyrenoid

A protein- and starch-containing storage body located inside the chloroplasts of many green algae.

Bryophytes

Non-vascular land plants (mosses and liverworts) whose dominant phase is a haploid gametophyte that needs water for fertilisation.

Liverworts

A group of bryophytes with dorsiventral thalloid bodies; reproduce asexually via gemmae; e.g., Marchantia.

Mosses

Bryophytes exhibiting a protonema stage followed by upright leafy shoots; have a more elaborate sporophyte; e.g., Funaria, Sphagnum.

Protonema

The first, filamentous, juvenile stage of a moss gametophyte that arises directly from a spore.

Gemma

A small, green, multicellular asexual bud formed in gemma cups of liverworts that detaches to grow into a new plant.

Pteridophytes

First vascular land plants (ferns, horsetails, club mosses) with dominant sporophytes bearing true roots, stems, leaves and sporangia.

Strobilus

A cone-like structure made of compact sporophylls that bear sporangia, found in some pteridophytes and gymnosperms.

Homosporous plant

A species that produces only one type of spore, which typically develops into a bisexual gametophyte.

Heterosporous plant

A plant that forms two distinct spores—microspores and megaspores—giving rise to male and female gametophytes, respectively.

Gymnosperms

Seed plants with exposed (‘naked’) ovules and seeds; include conifers such as Pinus, Cycas and Ginkgo.

Mycorrhiza

A mutualistic association between plant roots and fungi that enhances nutrient and water uptake, common in gymnosperms like Pinus.

Angiosperms

Flowering plants whose ovules are enclosed within ovaries that develop into fruits; divided into monocotyledons and dicotyledons.