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Botany unit 3 Cheat Sheet (DRAFT) by

This is a draft cheat sheet. It is a work in progress and is not finished yet.

Pterid­ophytes (chapter 17)

Pterid­ophyte charac­ter­istics
They are vascular (they have roots, stems, and leaves)
The cells are cylind­rical or elongated, and network throughout the plant
Xylem moves water and ions (positive and negative) around the plant
Phloem moves organic molecules, like sugars, around the plants
The sporophyte is the dominant phase in the life cycle

Pterid­ophytes (chapter 17)

Club mosses - the Lycophytes
Selagi­nella is the only genus of the family Selagi­nel­laceae
Most are found in tropical areas, and a few (seven genera) are found in the US and Canada
The club mosses are homosp­orous
Selagi­nella has an herbaceous sporophyte that bears microp­hylls. Its sporop­hylls are arranged in strobili
Selagi­nella has a ligule (small, scalelike outgrowth) with unisexual gameto­phytes
The club mosses have sporangia, which are modified leaves (or leaf-like organs) that bear the spore-­pro­ducing sporangia
Each sporophyte of Selagi­nella has a single sporangium
In the US and Canada, nonpho­tos­ynt­hetic sporop­hylls are grouped into strobili (cones) at the ends of the aerial branches
Megasp­oro­phylls produce megasp­orangia
Spores of club mosses bring bisexual gameto­phytes about during germin­ation
Micros­por­ophylls produce micros­por­angia
Megasp­orangia and micros­por­angia occur in the same strobilus
The sperm of Selagi­nella require water to swim to the archegonia and fertilize the eggs. Fertil­ization occurs after the gameto­phytes have been shed from the strobilus
Isoetes, the quillw­orts, is the only genus of the family Isoetaceae
Isoetes is hetero­sporus

Pter­ido­phytes (chapter 17)

Ferns - the Monilo­phytes
The phylum Monilo­phyta is made up of the ferns and horsetails
There are four major lineages of the Monilo­phytes: the Psilot­opsida, the Maratt­iop­sida, the Polypo­dio­psida, and the Equise­topsida
Ferns are either euspor­angiate or leptos­por­ang­iate, in terms of the structure and method of develo­pment of their sporangia
In a euspor­angium, the parent cells (or initials) are located at the surface of the tissue from which the sporangium is produced
Leptos­por­angia come from a single superf­icial parent cell, which divides transv­ersely or obliquely
Sporangia are stalked, and each has a special layer of unevenly thick-­walled cells called an annulus
The leaves, or fronds, of the Polypo­dio­psida are called fronds. The fronds are megaph­ylls, and they're the most conspi­cuous part of the sporophyte
The ferns are the only seedless vascular plants to have well-d­eve­loped megaphylls
The fronds are compound; the lamina is divided into pinnae (leafl­ets), which are attached to the rachis (extension of the leaf stalk)
In almost all ferns, the young leaved are circinate (coiled), and they're referred to as "­fid­dle­hea­ds"
Circinate venation refers to the type of leaf develo­pment in which leaves of young ferns are curled
In many genera of ferns, young sori are covered by specia­lized outgrowths of the leave called the indusia (singular: indusium)
The sporangia occur in clusters called sori (singular: sorus)
Gameto­phytes typically develop rapidly into a flat, heart-­shaped structure called the prothallus
The water ferns are hetero­spo­rous, leptos­por­angiate ferns
The rhizomes of the water ferns grow in the mud, in damp soil, or often with the leaves floating on the surface of the water
The leaves of Marsilea resemble the leaves of a four-leaf clover
Azolla and Salvinia are small ferns that float on top of the water

Gymnos­perms: chapter 18

Conife­rophyta (the conifers)
Cycado­phyta (the cycads)
Ginkgo­phyta (ginkgo, or maidenhair tree
Gnetophyta (the gnetop­hytes)


Charac­ter­istics of gymnos­perms
Seeded, vascular plants
There are extinct and living gymnos­perms
The extinct gymnos­perms are the seed ferns and the cordaites
There are four phyla of living gymnos­perms. They are: Conife­rophyta (the conifers), Cycado­phyta (the cycads), Gingko­phyta (the gingko, or maiden­hair, tree), and Gnetophyta (the gnetop­hytes)
Their seeds and ovules are exposed on sporop­hylls (modified leaves)
Microg­ame­top­hytes (male gameto­phytes) develop as pollen grain. Water isn't required as a medium for transp­orting the sperm to the egg
Pollin­ation is when the pollen grain (partly developed microg­ame­top­hyte) is transf­erred bodily to the vicinity of a megaga­met­ophyte (female gameto­phyte) within an ovule