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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

If Jane was in room(B) while her mother Stella was in room (Y). Jane was cooking fish, her mother came to smell the good scent, By what process did her mother came to smell the scent
Neimar Reply
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Joseph
how many days do a bean seed take to germinate
Nando
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Yahaya Reply
genetic information
MG
Deoxyribonucliec acid (DNA) is the cell's hereditary material that contains instructions for growth, development and reproduction.
Joseph
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describe an experiment to show that plants require light for photosynthesis
Diyara Reply
What's an amoeba
Bigger Reply
An amoeba is a cell or an organism that has the ability to ulter it's shape.
Joseph
An amoeba has an irregular shape and it changes constantly,it's a unicellular organism belong to a group called protists it has a pseudopodia used for locomotion and ingestion...
Emmanuel
what is a zygote?
Darius Reply
zygote is a eukaryotic cell formed by a fertilization event between two gametes. The zygote's genome is a combination of the DNA in each gamete, and contains all of the genetic information necessary to form a new individual.
MG
A zygote is an organism formed after fertilization
Neimar
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Van
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Darius
Zygote is located inside the ovule, which is present in the ovary.
MG
zygote is a eukaryotic cell formed by a fertilization event between two gametes. The zygote's genome is a combination of the DNA in each gamete, and contains all of the genetic information necessary to form a new individual.
MG
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Aadan Reply
biology is the study of living n non living organism
Kelsia
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Kelsia
Biology is the branch of science that deals with the study of living and non living things
Neimar
Describe at least two major changes to the animal phylogenetic tree that have come about due to molecular or genetic findings.
Tamala Reply
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Ramreichon Reply
Which of the following is not a characteristics of all living organisms? A. Excretion B. Photosynthesis C. Reproduction D. Respiration
Abel
B.
Anastasiya
B photosynthesis
Survive
general equation for photosynthesis
Ojasope Reply
6CO2 + 6H2O + solar energy= C6H1206+ 6O2
Anastasiya
meaning of amino Acids
AJAYI Reply
An aminoacid is a base unit molecule for proteins. It s formed by a central Carbon, to which are attached: an amminic Group, a carbossilic Group, an H hydrogen, and an R group ( which varies for each different aminoacid). Glycin is the only aminoacid to have for an R group a simple H hydrogen.
Anastasiya
H NH2-C-COOH R this is the not ionized form but usually they are ionized, with NH+ and COO-
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The R group, the lateral Chain, is responsible for the characteristics of the aminoacid.
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* NH2+
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Van
a diagram of an adult mosquito
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what are white blood cells
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white blood cell is part of the immune system. that help fight the infection.
MG
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Mlungisi
Cells with a similar function, form a tissue. For example the nervous tissue is composed by cells:neurons and glia cells. Muscle tissue, is composed by different cells.
Anastasiya
white blood cells are components of blood that help the body fight diseases
Neimar
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Anastasiya
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Lish
Yes
ANDY
Please define mitosis for me
Juliet
mitosis is a process where a single cell divides into two identical daughter cells(cell division)
Sani
Kk
Juliet
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Sani
What about meiosis
Juliet
Meiosis is a process that produces gametes. From a single cell, 4 daughter cells (gametes) are formed.
Anastasiya
What is a tissue respiration
Juliet

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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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