botany 4

Alteration of generation

The life cycle of plants that alternates between a diploid sporophyte generation and a haploid gametophyte generation.

Antheridium

The male reproductive organ in lower plants, producing sperm.

Archegonium

The female reproductive organ in lower plants, containing a single egg.

Calyptra

A hood-like structure covering the developing sporophyte in some lower plants, typically formed from the archegonium.

Capsule

The part of the sporophyte that contains spores; also called sporangium.

Dioecious

Having male and female reproductive structures on separate individuals.

Diploid

Containing a full set of chromosomes (2n).

Elaters

Elongated cells found in the sporangia of liverworts and hornworts that twist and untwist with changes in humidity, aiding in spore dispersal.

Enations

Tiny, flap-like photosynthetic structures found spiraling around the stem of whisk ferns.

Endodermis

A layer of cells in the vascular tissue of plants, sometimes providing insulation.

Fertilization

The fusion of sperm and egg to form a zygote.

Foot

The basal part of the sporophyte that attaches to the gametophyte and absorbs nutrients.

Gametophyte

The haploid generation in the plant life cycle that produces gametes (sperm and eggs).

Gemmae

Small, multicellular asexual reproductive structures found on the thallus of some liverworts.

Haploid

Containing half a set of chromosomes (n).

Heterospory

The production of two different types of spores, microspores (male) and megaspores (female).

Homospory

The production of only one type of spore, which develops into a bisexual gametophyte.

Hyphoids

Single-celled, thin tissue structures found in mosses.

Megaphyll

A large leaf with complex venation, characteristic of ferns and seed plants.

Megasporangia

Sporangia that produce megaspores.

Megaspore

A large haploid spore that develops into a female gametophyte.

Megasporocyte

A diploid cell within the megasporangium that undergoes meiosis to produce megaspores.

Megasporophyll

A modified leaf or leaf-like structure that bears megasporangia.

Meiosis

A type of cell division that reduces the number of chromosomes by half, producing haploid cells.

Mesophyll

The tissue in the interior of a leaf, containing chloroplasts for photosynthesis.

Microatmosphere

A localized climate created by dense plant growth, influencing moisture and temperature.

Micropyle

A small opening in the ovule through which pollen can enter for fertilization.

Microsporangia

Sporangia that produce microspores.

Microspore

A small haploid spore that develops into a male gametophyte.

Microsporophyll

A modified leaf or leaf-like structure that bears microsporangia.

Mucilage

A viscous fluid produced in the pores of hornwort thalli that houses nitrogen-fixing bacteria.

Non-vascular plants

Plants that lack vascular tissue (xylem and phloem).

Ovule

A structure in seed plants containing the female gametophyte and egg, which develops into a seed after fertilization.

Phloem

Vascular tissue in plants that transports sugars and other organic compounds.

Pollen cones

Male strobili (cones) in gymnosperms that produce pollen.

Pollen grain

The male gametophyte of seed plants.

Pollen tube

A tube that grows from a pollen grain to deliver sperm to the ovule.

Prothallus

The gametophyte stage of ferns and some other seedless vascular plants.

Protonema

A thread-like or plate-like structure formed after spore germination in mosses and some liverworts, from which the gametophyte plant develops.

Resin

An aromatic and anti-septic secretion in some plants, like pines, that prevents fungal growth and insect attacks.

Rhizoids

Single-celled or multicellular root-like filaments that anchor non-vascular plants to the substrate and absorb water and nutrients.

Rhizome

An underground horizontal stem that can produce new shoots and roots.

Seed cones

Female strobili (cones) in gymnosperms that contain ovules and produce seeds.

Seedless vascular plants

Plants that possess vascular tissue but do not produce seeds.

Sori

Clusters of sporangia on the underside of fern fronds.

Sporangium

A structure in which spores are produced.

Spore

A haploid reproductive cell that can develop into a new organism without fusion with another cell.

Sporophyte

The diploid generation in the plant life cycle that produces spores.

Sporophyll

A modified leaf or leaf-like structure that bears sporangia.

Stomata

Pores on the surface of leaves and stems that regulate gas exchange.

Strobili

Cone-like structures composed of sporophylls arranged in a spiral or whorl; found in some seedless vascular plants and gymnosperms.

Thallus

A flattened, undifferentiated plant body, characteristic of some liverworts and hornworts.

Vascular tissue

Tissues in plants (xylem and phloem) that transport water, nutrients, and sugars.

Whorls

An arrangement of leaves, branches, or flowers in a circle around a stem at a single node.

Xylem

Vascular tissue in plants that transports water and minerals from the roots to the rest of the plant.

Zygote

A diploid cell formed by the fusion of sperm and egg.