Glossary — Plant Kingdom Key Terms — Notes | NoteTube

Term	Definition	Context
Thallus	Undifferentiated plant body lacking true roots, stems, and leaves	Algae, liverworts
Gametophyte	Haploid (n) phase of plant life cycle; produces gametes by mitosis	All plant groups
Sporophyte	Diploid (2n) phase; produces spores by meiosis	All plant groups
Alternation of generations	Cyclic alternation between haploid gametophyte and diploid sporophyte	Universal in plants
Antherozoid	Flagellated male gamete (sperm) of bryophytes and pteridophytes	Bryophytes, Pteridophytes
Archegonium	Flask-shaped female sex organ containing the egg	Bryophytes, Pteridophytes, Gymnosperms
Protonema	Filamentous, algae-like juvenile stage of moss gametophyte, developing from spore	Mosses (Bryophyta)
Gametophore	Upright, leafy adult stage of the moss gametophyte	Mosses (Bryophyta)
Prothallus	Small, heart-shaped, independent gametophyte of pteridophytes	Pteridophyta
Gemma (pl. gemmae)	Multicellular, haploid asexual propagule in Marchantia gemma cups	Marchantia (liverwort)
Homosporous	Producing only one type of spore	Most pteridophytes
Heterosporous	Producing two types of spores (mega and micro)	Selaginella, Salvinia
Megaspore	Large spore → female gametophyte	Selaginella, Salvinia, seed plants
Microspore	Small spore → male gametophyte	Selaginella, Salvinia, seed plants
Pollen tube	Tube grown by germinating pollen grain to deliver sperm to egg	Gymnosperms, Angiosperms
Double fertilization	Two fusion events in angiosperms — embryo (2n) + endosperm (3n)	Angiosperms only
Endosperm	Triploid (3n) nutritive tissue in angiosperm seeds; formed by triple fusion	Angiosperms
Embryo sac	7-celled, 8-nucleate female gametophyte of angiosperms	Angiosperms
Fucoxanthin	Brown accessory pigment of Phaeophyceae	Brown algae
Phycoerythrin	Red accessory pigment of Rhodophyceae; absorbs blue-green light	Red algae
Laminarin	Food reserve polysaccharide of brown algae	Phaeophyceae
Floridean starch	Food reserve polysaccharide of red algae; similar to amylopectin	Rhodophyceae
Agar	Sulphated galactan polysaccharide from red algae; used as culture medium	Gelidium, Gracilaria
Algin	Alginic acid from brown algae cell walls; used as industrial thickener	Phaeophyceae
Living fossil	Organism that has remained morphologically unchanged for millions of years	Ginkgo, Cycas
Naked seed	Seed not enclosed in fruit; characteristic of gymnosperms	Gymnosperms
Dioecious	Having separate male and female individuals (plants)	Cycas, Ginkgo
Monoecious	Both male and female reproductive structures on same plant	Pinus