Lycopodiopsida
Encyclopedia
Lycopodiopsida is a class of plants often loosely grouped as the fern allies
. Traditionally the group included not only the clubmosses and firmosses, but also the spikemosses (Selaginella and relatives) and the quillworts (Isoetes and relatives). However, the latter are now usually separated off into a separate class, Isoetopsida
.
Clubmosses are thought to be structurally similar to the earliest vascular plant
s, with small, scale-like leaves, homosporous spore
s borne in sporangia
at the bases of the leaves, branching stems (usually dichotomous), and generally simple form.
The Class Lycopodiopsida as interpreted here contains a single living order, the Lycopodiales, and a single extinct order, the Drepanophycales
.
DNA
produced the cladogram
shown below (reproduced here to genus level only), confirming the monophyly of the four genera, and their distance from Isoetes.
The genera fall into two distinct clades, but there is, as yet, no consensus as to whether to recognize them in a single family, Lycopodiaceae, or to separate them into two families: a more narrowly defined Lycopodiaceae and Huperziaceae.
The Family Lycopodiaceae
, as narrowly defined, comprises the extant genus, Lycopodium
, which includes the Wolf's-foot clubmoss, Lycopodium clavatum
, Ground-pine, Lycopodium obscurum
, Southern ground-cedar, Lycopodium digitatum, and other species. Also included are species of Lycopodiella
, such as the Bog clubmoss, Lycopodiella inundata
. Most of the Lycopodium favor acidic, sandy, upland sites, whereas most of the Lycopodiella favor acidic, boggy sites.
The other major group, the Family Huperziaceae
, are known as the firmosses. This group includes the genus Huperzia, such as the Shining firmoss, Huperzia lucidula, the Rock firmoss, Huperzia porophila, and the Northern firmoss, Huperzia selago. This group also includes the odd, tuberous Australasia
n plant Phylloglossum
, which was, until recently, thought to be only remotely related to the clubmosses. However, as the cladogram above shows, it is closely related to the genus Huperzia.
A powder known simply as lycopodium, consisting of dried spores of the common clubmoss, was used in Victorian theater to produce flame-effects. A blown cloud of spores burned rapidly and brightly, but with little heat. It was considered safe by the standards of the time.
Fern ally
Fern allies are a diverse group of seedless vascular plants that are not true ferns. Like ferns, a fern ally disperses by shedding spores to initiate an alternation of generations.-Classification:...
. Traditionally the group included not only the clubmosses and firmosses, but also the spikemosses (Selaginella and relatives) and the quillworts (Isoetes and relatives). However, the latter are now usually separated off into a separate class, Isoetopsida
Isoetopsida
The Isoetopsida is a class of the Lycopodiophyta. All living plants belong to the genus Selaginella in the Selaginellales or to Isoetes in the order Isoetales. In the past, members of this group have sometimes been placed in the class Isoetopsida, sometimes in the Selaginellopsida or Lycopodiopsida...
.
Clubmosses are thought to be structurally similar to the earliest vascular plant
Vascular plant
Vascular plants are those plants that have lignified tissues for conducting water, minerals, and photosynthetic products through the plant. Vascular plants include the clubmosses, Equisetum, ferns, gymnosperms and angiosperms...
s, with small, scale-like leaves, homosporous spore
Spore
In biology, a spore is a reproductive structure that is adapted for dispersal and surviving for extended periods of time in unfavorable conditions. Spores form part of the life cycles of many bacteria, plants, algae, fungi and some protozoa. According to scientist Dr...
s borne in sporangia
Sporangium
A sporangium is an enclosure in which spores are formed. It can be composed of a single cell or can be multicellular. All plants, fungi, and many other lineages form sporangia at some point in their life cycle...
at the bases of the leaves, branching stems (usually dichotomous), and generally simple form.
The Class Lycopodiopsida as interpreted here contains a single living order, the Lycopodiales, and a single extinct order, the Drepanophycales
Drepanophycales
Drepanophycales is an order of extinct plants of the Division Lycopodiophyta of ?Late Silurian to Late Devonian age , found in North America, China, Russia, Europe, and Australia. Sometimes known as the Asteroxylales or Baragwanathiales....
.
Order Lycopodiales
The classification of this group has been unsettled in recent years and a consensus is yet to emerge. Older classifications took a very broad definition of the genus Lycopodium that included virtually all the species of Lycopodiales. The trend in recent years has been to define Lycopodium more narrowly and to classify the other species into several genera, an arrangement that has been supported by both morphological and molecular data and adopted in numerous revisions and flora treatments. Starting from the four genera accepted by Øllgaard, a study based on chloroplastChloroplast
Chloroplasts are organelles found in plant cells and other eukaryotic organisms that conduct photosynthesis. Chloroplasts capture light energy to conserve free energy in the form of ATP and reduce NADP to NADPH through a complex set of processes called photosynthesis.Chloroplasts are green...
DNA
DNA
Deoxyribonucleic acid is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms . The DNA segments that carry this genetic information are called genes, but other DNA sequences have structural purposes, or are involved in...
produced the cladogram
Cladogram
A cladogram is a diagram used in cladistics which shows ancestral relations between organisms, to represent the evolutionary tree of life. Although traditionally such cladograms were generated largely on the basis of morphological characters, DNA and RNA sequencing data and computational...
shown below (reproduced here to genus level only), confirming the monophyly of the four genera, and their distance from Isoetes.
The genera fall into two distinct clades, but there is, as yet, no consensus as to whether to recognize them in a single family, Lycopodiaceae, or to separate them into two families: a more narrowly defined Lycopodiaceae and Huperziaceae.
The Family Lycopodiaceae
Lycopodiaceae
The Lycopodiaceae is a family of primitive vascular plants, including all of the core clubmosses. These plants bear spores on specialized structures at the apex of a shoot; they resemble a tiny battle club, from which the common name derives...
, as narrowly defined, comprises the extant genus, Lycopodium
Lycopodium
Lycopodium is a genus of clubmosses, also known as ground pines or creeping cedar, in the family Lycopodiaceae, a family of fern-allies...
, which includes the Wolf's-foot clubmoss, Lycopodium clavatum
Lycopodium clavatum
Lycopodium clavatum is the most widespread species in the genus Lycopodium of the clubmoss family Lycopodiaceae....
, Ground-pine, Lycopodium obscurum
Lycopodium obscurum
Lycopodium obscurum, commonly called ground pine or princess pine, is a species of clubmoss in the family Lycopodiaceae. It is a close relative of other treelike Lycopodium such as L. dendroideum and L. Hickeyi. It is distributed from Alabama to the east coast of the United States, and north into...
, Southern ground-cedar, Lycopodium digitatum, and other species. Also included are species of Lycopodiella
Lycopodiella
Lycopodiella is a genus in the clubmoss family Lycopodiaceae. The genus members are commonly called bog clubmosses, describing their wetland habitat. There are 38 species; the distribution is cosmopolitan, with centres of diversity in the tropical New World and New Guinea...
, such as the Bog clubmoss, Lycopodiella inundata
Lycopodiella inundata
Lycopodiella inundata is a species of club moss known by the common names inundated club moss, marsh club moss and northern bog club moss. It has a circumpolar and circumboreal distribution, occurring throughout the northern Northern Hemisphere from the Arctic to montane temperate regions in...
. Most of the Lycopodium favor acidic, sandy, upland sites, whereas most of the Lycopodiella favor acidic, boggy sites.
The other major group, the Family Huperziaceae
Huperziaceae
The family Huperziaceae is one of two families sometimes recognized in the order Lycopodiales, and contains two or three extant genera:*Huperzia ; 10-15 species; terrestrial....
, are known as the firmosses. This group includes the genus Huperzia, such as the Shining firmoss, Huperzia lucidula, the Rock firmoss, Huperzia porophila, and the Northern firmoss, Huperzia selago. This group also includes the odd, tuberous Australasia
Australasia
Australasia is a region of Oceania comprising Australia, New Zealand, the island of New Guinea, and neighbouring islands in the Pacific Ocean. The term was coined by Charles de Brosses in Histoire des navigations aux terres australes...
n plant Phylloglossum
Phylloglossum
Phylloglossum, a genus in the clubmoss family Huperziaceae, is a small plant superficially resembling a tiny grass plant, growing with a rosette of slender leaves 2-5 cm long from an underground bulb-like root...
, which was, until recently, thought to be only remotely related to the clubmosses. However, as the cladogram above shows, it is closely related to the genus Huperzia.
A powder known simply as lycopodium, consisting of dried spores of the common clubmoss, was used in Victorian theater to produce flame-effects. A blown cloud of spores burned rapidly and brightly, but with little heat. It was considered safe by the standards of the time.