[botany lec] spores and cones

Sporophylls

Modified leaves that produce sporangia (which become spores)

Homosporous plants

Most ferns and its relatives (except Selaginella)

Heterosporous plants

All seed plants (angiosperm and gymnosperms) and some seedless plants.

Spores

something that is present in bryophytes (Moss, liverworts, hornworts) and ferns and its relatives

Calyptra

a maternal structure that protects the sporophyte offspring from dehydration, and positively impacts sporophyte survival and fitness in mosses.

Capsule

part of the moss that stores the spores

Operculum

part of the moss that is a cap-like covering that detaches to release spores

Leafy and Thalloid liverworts

two basic groups of liverworts

leafy liverworts

Group of liverworts that resemble a moss; its gametophyte consists of thin blades on a slender stipe

Thalloid liverworts

In this group of liverwort, gametophyte is flat and ribbon-like or heart-shaped and bilaterally symmetrical - this shape is called a thallus

Gemmae cups

small, intact, complete pieces of plant that are produced in a cup on the surface of the thallus and develop into gametophytes through asexual reproduction

Pseudoelaters

surround the spores and help propel them further in the environment

Columella

small column of tissue

Ferns

mostly homosporous, reproduce using spores contained in sori (sorus), Lightweight and easily disperse by water and wind. Protected inside a sporangium

Sori

clustered/aggregate sporangia, contains and produce spores

Indusium

thin membranous covering a sorus

Sporangium

an enclosure in which spores are formed.

Sporophylls

sporangium-bearing leaves

Strobili

terminal cone-like structures which bears the sporangium containing sporocytes

Cones

this is found in most species of gymnosperms

Microspores (male gametophytes) and megaspores (female gametophytes)

Kinds of spores produced by gymnosperms

Pollen cones (male strobili)

consists of papery or membranous scales called microsporophylls, arranged in spiral or whorls.

Microsporangia

develop in pairs towards the bases of the scales; it -houses the microsporocytes which undergo meiosis to produce microspores which eventually develop into pollen

Pollen grain

immature male gametophyte; produces pollen tube which slowly grows to the nucellus where the archegonia develop

Megaspores

are produced in megasporangia located within ovules at the bases of the seed cone scales, called megasporophylls.

Megasporangium

Each ovule has within it a ________ containing the nucellus and a single megasporocyte

Integument

thick layers surrounding the ovule, one of which becomes the seed coat

Micropyle

tubular channel or pore

Nucellus

food source of the growing gametophyte

hornwort

what kind of liverwort is this?