Lycopodium obscurum
Encyclopedia
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 Canada
. Newfoundland
is in the northeast corner of its range. It grows in the understory
of temperate coniferous and deciduous forests
, where it is involved in seral
secondary succession
, growing in clonal colonies some years after disturbance has occurred.
, however its main stem is actually a subterranea
n, creeping rhizome
, which grows about 6 cm below ground. Several aerial shoots branch off of the rhizome, which also branch dichotomously
several times, giving L. obscurum its distinctive appearance. Fertile shoots possess sessile strobili, borne at the tops of their main axes and sometimes at the tips of dominant lateral branches. The leaves are microphylls, each containing only a single vein and measuring less than 1 cm long. Two types of microphylls are formed, green trophophylls that cover most of the aerial shoots, and yellow to tan sporophyll
s that form the strobili, and contain the sporangia. L. obscurum reproduces sexually
via spores and also vegetatively
, through its rhizome.
The gametophyte
of L. obscurum is disc shaped prothallus, measuring an average of 1.5 cm. It closely resembles other gametophytes of genus Lycopodium, so it cannot be identified by gametophyte alone. Doing so would be difficult nonetheless, as this type of gametophyte grows only underground, years after a disturbance has taken place. Therefore, the compact soil caused by repeated human traffic would disturb these areas and L. obscurum spores would not germinate, and put pressure on living gametophyes and attached sporophytes.
Every year, a main rhizome produces one aerial shoot, but in the case of a plant with multiple main rhizomes a new shoot is produced from each. The age of a shoot corresponds to the layers of compressed microphylls in its stem, caused by growth halting each winter, the same way as tree rings are formed. Shoot morphology
can also be used to estimate their ages. First year shoots are unbranched and usually do not penetrate the soil surface. Second year shoots undergo rapid growth, usually reaching near their final heights, and forming several systems of lateral branches. Branching occurs only in the second, and sometimes third years. Strobili can be formed as early as the second growing season, but usually begin to be produced in the third. Strobilus production can continue through the fourth year, and shoots die in either the fourth or fifth year.
from the wild for use as Christmas
greens for wreaths, as well as the use of its spores for flash powder
. While flash powder is now practically obsolete, the harvest of L. obscurum has caused it to become threatened in several areas, leading Indiana and New York to declare it protected by state law
. When harvesting legally, it is recommended to cut the shoots using shears to minimize rhizome damage, alternate sites every year, and select only individuals possessing stribili with open sporophylls. This ensures that immature shoots are not harvested, and will be allowed an attempt at reproduction.
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...
. It is a close relative of other treelike 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...
such as L. dendroideum
Lycopodium dendroideum
Lycopodium dendroideum is a clubmoss native to the northeastern United States. It is part of a complex of species colloquially known as groundpine and which was originally all lumped under the species Lycopodium obscurum. This species was known as L. obscurum L. var...
and L. Hickeyi. It is distributed from Alabama
Alabama
Alabama is a state located in the southeastern region of the United States. It is bordered by Tennessee to the north, Georgia to the east, Florida and the Gulf of Mexico to the south, and Mississippi to the west. Alabama ranks 30th in total land area and ranks second in the size of its inland...
to the east coast of the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
, and north into Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
. Newfoundland
Newfoundland and Labrador
Newfoundland and Labrador is the easternmost province of Canada. Situated in the country's Atlantic region, it incorporates the island of Newfoundland and mainland Labrador with a combined area of . As of April 2011, the province's estimated population is 508,400...
is in the northeast corner of its range. It grows in the understory
Understory
Understory is the term for the area of a forest which grows at the lowest height level below the forest canopy. Plants in the understory consist of a mixture of seedlings and saplings of canopy trees together with understory shrubs and herbs...
of temperate coniferous and deciduous forests
Temperate deciduous forest
A temperate deciduous forest, more precisely termed temperate broadleaf forest or temperate broadleaved forest, is a biome found in North America, southern South America, Europe, and Asia. A temperate deciduous forest consists of trees that lose their leaves every year...
, where it is involved in seral
Seral community
A seral community is an intermediate stage found in ecological succession in an ecosystem advancing towards its climax community. In many cases more than one seral stage evolves until climax conditions are attained...
secondary succession
Secondary succession
Secondary succession is one of the two types of ecological succession of plant life. As opposed to the first, primary succession, secondary succession is a process started by an event that reduces an already established ecosystem Secondary succession is one of the two types of ecological...
, growing in clonal colonies some years after disturbance has occurred.
Description
Lycopodium obscurum is known for the treelike appearance of its sporophyteSporophyte
All land plants, and some algae, have life cycles in which a haploid gametophyte generation alternates with a diploid sporophyte, the generation of a plant or algae that has a double set of chromosomes. A multicellular sporophyte generation or phase is present in the life cycle of all land plants...
, however its main stem is actually a subterranea
Subterranea (geography)
Subterranea refers to underground structures, both natural and man-made . Some subterranea include:* Bunker* Casemate* Catacombs* Caves** Ice caves* Cave dwellings, Cave house* Cave temple* Cellar* Cenote* Dungeon...
n, creeping rhizome
Rhizome
In botany and dendrology, a rhizome is a characteristically horizontal stem of a plant that is usually found underground, often sending out roots and shoots from its nodes...
, which grows about 6 cm below ground. Several aerial shoots branch off of the rhizome, which also branch dichotomously
Dichotomy
A dichotomy is any splitting of a whole into exactly two non-overlapping parts, meaning it is a procedure in which a whole is divided into two parts...
several times, giving L. obscurum its distinctive appearance. Fertile shoots possess sessile strobili, borne at the tops of their main axes and sometimes at the tips of dominant lateral branches. The leaves are microphylls, each containing only a single vein and measuring less than 1 cm long. Two types of microphylls are formed, green trophophylls that cover most of the aerial shoots, and yellow to tan sporophyll
Sporophyll
A sporophyll is a leaf that bears sporangia. Both microphylls and megaphylls can be sporophylls. In heterosporous plants, sporophylls bear either megasporangia , or microsporangia...
s that form the strobili, and contain the sporangia. L. obscurum reproduces sexually
Plant sexuality
Plant sexuality covers the wide variety of sexual reproduction systems found across the plant kingdom. This article describes morphological aspects of sexual reproduction of plants....
via spores and also vegetatively
Vegetative reproduction
Vegetative reproduction is a form of asexual reproduction in plants. It is a process by which new individuals arise without production of seeds or spores...
, through its rhizome.
The gametophyte
Gametophyte
A gametophyte is the haploid, multicellular phase of plants and algae that undergo alternation of generations, with each of its cells containing only a single set of chromosomes....
of L. obscurum is disc shaped prothallus, measuring an average of 1.5 cm. It closely resembles other gametophytes of genus Lycopodium, so it cannot be identified by gametophyte alone. Doing so would be difficult nonetheless, as this type of gametophyte grows only underground, years after a disturbance has taken place. Therefore, the compact soil caused by repeated human traffic would disturb these areas and L. obscurum spores would not germinate, and put pressure on living gametophyes and attached sporophytes.
Identification
Identifying L. obscurum in the wild can be difficult without prior study, because it is not only relatively rare, but shares much of its morphology with L. dendroideum and L. Hickeyi. However, it can be identified with the naked eye by observing its leaves. Below its first branch, the microphylls of L. obscurum are tightly packed to the axis, while those of L. dendroideum are fully spread down to the soil. The leaves on lateral branches of L. dendroideum and L. Hickeyi are evenly shaped and distributed, while they are pressed into the horizontal plane in L. obscurum, with the underside leaves being much shorter than all others.Growth Pattern
The rhizome of L. obscurum typically produces only one upright shoot per year and grows in a single direction. In the beginning of a growing season, the rhizome grows a few centimeters and then forms one branch at a 90°, alternating sides each year, which remains only millimeters in length. It then grows another couple of centimeters and then again branches off to the same side to form an aerial shoot. The rhizome branch produced each year is usually very weak and dies the next, but sometimes becomes a new main rhizome. This happens if the plant is especially productive, or more frequently if the tip of the main rhizome is damaged so that it cannot grow. When a new main rhizome is formed, it makes a second 90° turn so that it is growing in the same direction as the rhizome from which it came. All underground branching occurs parallel to the ground, so upright shoots must then orient themselves appropriately in order to emerge from the soil.Every year, a main rhizome produces one aerial shoot, but in the case of a plant with multiple main rhizomes a new shoot is produced from each. The age of a shoot corresponds to the layers of compressed microphylls in its stem, caused by growth halting each winter, the same way as tree rings are formed. Shoot morphology
Morphology (biology)
In biology, morphology is a branch of bioscience dealing with the study of the form and structure of organisms and their specific structural features....
can also be used to estimate their ages. First year shoots are unbranched and usually do not penetrate the soil surface. Second year shoots undergo rapid growth, usually reaching near their final heights, and forming several systems of lateral branches. Branching occurs only in the second, and sometimes third years. Strobili can be formed as early as the second growing season, but usually begin to be produced in the third. Strobilus production can continue through the fourth year, and shoots die in either the fourth or fifth year.
Uses and Conservation
Historically, L. obscurum has been harvestedHarvest
Harvest is the process of gathering mature crops from the fields. Reaping is the cutting of grain or pulse for harvest, typically using a scythe, sickle, or reaper...
from the wild for use as Christmas
Christmas
Christmas or Christmas Day is an annual holiday generally celebrated on December 25 by billions of people around the world. It is a Christian feast that commemorates the birth of Jesus Christ, liturgically closing the Advent season and initiating the season of Christmastide, which lasts twelve days...
greens for wreaths, as well as the use of its spores for flash powder
Lycopodium powder
Lycopodium powder is a yellow-tan dust-like powder historically used as a flash powder. It is composed of the dry spores of clubmoss plants, various fern relatives principally in the genera Lycopodium and Diphasiastrum...
. While flash powder is now practically obsolete, the harvest of L. obscurum has caused it to become threatened in several areas, leading Indiana and New York to declare it protected by state law
State law
In the United States, state law is the law of each separate U.S. state, as passed by the state legislature and adjudicated by state courts. It exists in parallel, and sometimes in conflict with, United States federal law. These disputes are often resolved by the federal courts.-See also:*List of U.S...
. When harvesting legally, it is recommended to cut the shoots using shears to minimize rhizome damage, alternate sites every year, and select only individuals possessing stribili with open sporophylls. This ensures that immature shoots are not harvested, and will be allowed an attempt at reproduction.