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Ferns and other seedless vascular plants

By the late Devonian period, plants had evolved vascular tissue, well-defined leaves, and root systems. With these advantages, plants increased in height and size. During the Carboniferous period, swamp forests of club mosses and horsetails—some specimens reaching heights of more than 30 m (100 ft)—covered most of the land. These forests gave rise to the extensive coal deposits that gave the Carboniferous its name. In seedless vascular plants, the sporophyte became the dominant phase of the lifecycle.

Water is still required for fertilization of seedless vascular plants, and most favor a moist environment. Modern-day seedless tracheophytes include club mosses, horsetails, ferns, and whisk ferns.

Phylum lycopodiophyta: club mosses

The club mosses    , or phylum Lycopodiophyta , are the earliest group of seedless vascular plants. They dominated the landscape of the Carboniferous, growing into tall trees and forming large swamp forests. Today’s club mosses are diminutive, evergreen plants consisting of a stem (which may be branched) and microphylls ( [link] ). The phylum Lycopodiophyta consists of close to 1,200 species, including the quillworts ( Isoetales ), the club mosses ( Lycopodiales ), and spike mosses ( Selaginellales ), none of which are true mosses or bryophytes.

Lycophytes follow the pattern of alternation of generations seen in the bryophytes, except that the sporophyte is the major stage of the lifecycle. The gametophytes do not depend on the sporophyte for nutrients. Some gametophytes develop underground and form mycorrhizal associations with fungi. In club mosses, the sporophyte gives rise to sporophylls arranged in strobili, cone-like structures that give the class its name. Lycophytes can be homosporous or heterosporous.

 In the photo, seed-like strobili are arranged around the slender stalks of a club moss.
In the club mosses such as Lycopodium clavatum , sporangia are arranged in clusters called strobili. (credit: Cory Zanker)

Phylum monilophyta: class equisetopsida (horsetails)

Horsetails, whisk ferns and ferns belong to the phylum Monilophyta, with horsetails placed in the Class Equisetopsida. The single genus Equisetum is the survivor of a large group of plants, known as Arthrophyta, which produced large trees and entire swamp forests in the Carboniferous. The plants are usually found in damp environments and marshes ( [link] ).

 In the photo, bushy horsetail plants grow in water.
Horsetails thrive in a marsh. (credit: Myriam Feldman)

The stem of a horsetail is characterized by the presence of joints or nodes, hence the name Arthrophyta (arthro- = "joint"; -phyta = "plant"). Leaves and branches come out as whorls from the evenly spaced joints. The needle-shaped leaves do not contribute greatly to photosynthesis, the majority of which takes place in the green stem ( [link] ).

 Photo shows a horsetail plant, which resembles a scrub brush, with a thick stem and whorls of thin leaves branching from the stem.
Thin leaves originating at the joints are noticeable on the horsetail plant. Horsetails were once used as scrubbing brushes and were nicknamed scouring brushes. (credit: Myriam Feldman)

Silica collects in the epidermal cells, contributing to the stiffness of horsetail plants. Underground stems known as rhizomes anchor the plants to the ground. Modern-day horsetails are homosporous and produce bisexual gametophytes.

Questions & Answers

hello guys what's the difference between prokaryotes and eukaryotes
Nwachukwu Reply
deviation from mendelian
Ogali Reply
what is lethal allele
Ogali
Explain how chemical , bioligical and physical interaction between themselves and the non living components ?
Beyan Reply
what is Tissues
Faith Reply
Group of similar cells performing some related functions We have some type of tissues Connective Muscle Epithelial Nervous tissues
peter
group of cells that is called tissue.
Nikita
what is abiotic?
Williams Reply
state 2 abiotic factors that affect the rate of transpiration in plants?
Benenge
non living things
Chris
what is a cell
Esther Reply
structural and functional group is called cells
Nikita
what is contained in a smooth endoplasmic reticulum?
Bleyd Reply
sperm
Chris
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Jo
sorry i meant the structure within the smooth endoplasmic reticulum
Bleyd
ribosomes
Ogali
what is cell made of
Jo Reply
cytoplasm,cell wall and nucleus
Ogali
what is sponge
Joseph Reply
what is a photometer
Abigail Reply
what is respiration
Alao Reply
Is the release of energy from food substance in a living organism
innocent
What is cytoplasm
Nitta Reply
it is a gell like structure found in cell it contains the mitochondria, nucleus, lysosome etc
Ogali
in other words it's the material that contains the organelles of an organism
Nwachukwu
Parasitic adaptation of tapeworm
Angela Reply
Describe osmoregulator or osmoconformers and how these tools allow animals to adapt to different environment.
Alick Reply
describe the secondary function of a leaf to a plant.
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Source:  OpenStax, Biology. OpenStax CNX. Feb 29, 2016 Download for free at http://cnx.org/content/col11448/1.10
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