BSc Botany Unit 1: Archegoniates and Bryophytes

This set of vocabulary flashcards covers the fundamental concepts, structures, and characteristic features of Archegoniates and specific Bryophytes (Riccia, Marchantia, Anthoceros) as outlined in the Unit 1 Botany syllabus.

Archegoniates

A group of plants (Bryophytes, Pteridophytes, and Gymnosperms) characterized by possessing a multicellular female reproductive organ called the archegonium.

Archegonium

A flask-shaped multicellular female reproductive organ consisting of an elongated upper portion called the neck (cervix) and a swollen base called the venter containing the egg cell.

Embryophytes

An alternative name for archegoniates because the zygote develops into a multicellular embryo that is nourished and protected within the archegonium.

Bryophytes

Known as the "Amphibians of the Plant Kingdom," these are plants that can live on land but remain dependent on water for reproduction/fertilization.

Gametophyte

The dominant, haploid ($n$) phase of the bryophyte life cycle which is the prominent, long-lived, and independent plant body.

Sporophyte

The diploid ($2n$) phase of the bryophyte life cycle that is small, short-lived, and dependent on the gametophyte for nutrition.

Thallus

A simple, undifferentiated plant body that lacks true roots, stems, and leaves, and shows no vascular differentiation.

Rhizoids

Unicellular or multicellular hair-like structures located on the ventral surface of bryophytes used for attachment to the soil and water absorption.

Cuticle

A waxy layer on the surface of bryophytes that reduces water loss through evaporation, serving as an adaptation for terrestrial life.

Hepaticopsida

The class of bryophytes commonly known as liverworts, characterized by a liver-shaped thallus; includes the genera Riccia and Marchantia.

Dichotomously branched

A growth pattern where the plant body repeatedly forks into two equal branches, as seen in the thallus of Riccia and Marchantia.

Mid-dorsal groove

A shallow depression running along the middle of the upper (dorsal) surface of the Riccia thallus.

Oogamy

A type of sexual reproduction where the female gamete (egg) is large and non-motile, while the male gamete (sperm/antherozoid) is small and motile.

Riccia Sporophyte

The simplest sporophyte among the studied bryophytes, consisting only of a capsule and lacking both a foot and a seta.

Areolae

Diamond-shaped air pores on the dorsal surface of the Marchantia thallus used for gas exchange.

Gemmae Cups

Cup-shaped structures located on the dorsal surface of Marchantia that contain gemmae (multicellular bodies) for asexual reproduction.

Dioecious

A plant condition where male and female reproductive structures are produced on separate individuals, as seen in Marchantia.

Antheridiophore

The specialized upright stalk on a male Marchantia plant that bears the male sex organs (antheridia).

Archegoniophore

The specialized upright stalk on a female Marchantia plant that bears the female sex organs (archegonia).

Foot

The basal attachment structure of a sporophyte (present in Marchantia and Anthoceros) that anchors it to the gametophyte.

Seta

The stalk portion of a sporophyte that connects the foot to the capsule; it is absent in Riccia but present in Marchantia and Anthoceros.

Anthocerotopsida

The class of bryophytes known as hornworts, which includes the genus Anthoceros.

Mucilage cavities

Internal cavities in the Anthoceros thallus that house symbiotic nitrogen-fixing cyanobacteria like Nostoc.

Pyrenoid

A proteinaceous structure found within the single large chloroplast of Anthoceros cells, involved in starch synthesis and carbon fixation.

Meristematic base

A region of actively dividing tissue at the base of the Anthoceros sporophyte that allows for its characteristic continuous growth.

Columella

A sterile central column of tissue that runs through the length of the capsule in the Anthoceros sporophyte.

Elaters

Hygroscopic structures found within the capsule of certain bryophytes, such as Anthoceros, that assist in the dispersal of spores.