Licorice Fern

Cody Cruz (CC)

external image cool%20fern%20lolololz.jpgexotic-ferns-davenham-malvern-169788.jpg
(21) (DA)

Classification/Diagnostic Characteristics

Domain: Eukarya
Kingdom- Plantae
Phylum- Pteridophyta
Class- Pteridopsida
Order- Polypodiales
Family- Polypodiaceae
Genus- Polypodium
Species- Polypodium Glycyrrhiza

- Ferns are vascular plants meaning they can transport water and food throughout their bodies.
- Vascular system comprised of two types of tissues; xylem and phloem.
- The xylem conducts water and minerals from the soil to different parts of the plants.
- The phloem conducts products of photosynthesis from where they are produced to where they can be used and stored.
- Contain rigid structural support from lignin, which is found in the cell walls of tracheids.
- Vascular plants like ferns have branching sporophytes, which can produce more spores than an unbranched body

-Stems (the rhizome is an underground stem that has stringy roots)
-Roots that can be differentiated from the rhizome
-Leaves (frond are large leaves that play a crucial part in photosynthesis and reproduction; fiddleheads are made up of young fronds that are tightly coiled)
(11) (E.S.S.)

The licorice fern is identifiable by its long, pointed-triangular fronds (leaf of a fern) that are evergreen. They range from 10 to 70 cm in size. The leathery leaves are pinnately,divided once divided, with a light brown stripe. The rhizome (root-like structure) is scaly with a reddish-brown covering and has a sweet inside that tastes like licorice. The sori (seed-like sack) are oval to round located in a single row on both sides o the main vein on the underside of the leaf. The sori, sack of spores, do not have an indusium which is a membrane that covers the sori.[1] (SM)
Fern Plant Anatomy
Fern Plant Anatomy

Relationship to Humans

Ferns have been used for both indoor decoration and outdoor gardens and landscaping. A major value of ferns is in biological research, since they have retained such a primitive life cycle.

Several ferns also are known as invasive species and weeds. The immature leaves of the ostrich fern are eaten in the USA and the Huperzia serrata fern provides an alkaloid that has been significant in the control of epilepsy. In addition, aquatic nitrogen-fixing ferns in the genus mosquito fern are used in parts of Asia as green manure for rice fields and in India to feed cows for increased milk production. (10) (JF)

No ferns are grown as crops, however, the leaf buds of some ferns are harvested commercially to be canned. Moreover, ferns are often used in floral arrangements. Historically, fern spores were used as flash powder for photographers and were also used to coat rubber gloves. (7) (SJ)

Today, some herbalists are suggesting that ferns can be used as treatments for ulcers, rheumatism, intestinal infections, and other ailments as well. (9) (Shwetha)

One way that ferns hold a relationship to humans is its ability to maintain arsenic For example, the Chinese brake fern grows well in arsenic soil by accumulating large amounts of arsenic in its fronds, the portion of the fern that is above ground. As a result, humans grow brake ferns to "clean-up" soil that is contaminated with arsenic. (18) (MC)

Habitat and Niche
Fern species live in a wide variety of habitats, from remote mountain elevations, to dry desert rock faces, to bodies of water or open fields. Ferns can succeed in places where various environmental factors limit the success of other plants. Some ferns are among the world's most serious weed species, There are four particular types of habitats that ferns are found in: moist, shady forests; crevices in rock faces, acidic wetlands including bogs and swamps, and tropical trees.
Licorice ferns primarily live in costal forest areas on the west coast of the United States. This area extends up into Alaska and below California. They tend to grow in living or fallen tree branches, and on rock slabs. (LC) 15

Predator Avoidance

Since some ferns can grow in environments others can't, like acidic wetlands, they can accumulate toxic chemicals that could hurt and potentially kill their predator if consumed. When a predator sees that the fern can make it sick it will be less likely to consume it again.
Insects are a threat to ferns. A defense mechanism that ferns use is that they produce hydrogen cyanide immediately after an insect bites into it. They are also loaded with ecdysones, hormones that promote molting. (TM)

Nutrient Acquisition

Ferns acquire their nutrients through their vascular tissue system. Using the xylem, ferns can distribute water and mineral ions that were taken up by their roots, to all the cells of the stems and leaves. The water and mineral ions move through two types of conducting cells, trachieds and vessel elements. Ferns recieve their energy through the phloem. Phloem transports carbohydrates from photosynthetic sites (primarily leaves) to sites where they can be used or stored (sinks). The cells that make up the phloem are called sieve tube elements.

Reproduction and Life Cycle

What we know as ferns are the sporophytes of the plant. On the back of the sporophytes are sori which are clusters of sporangia. When environmental conditions are right the sporangium will release its spores. The spores will form a gametophyte which is where the sporophyte will sprout from. The gametophyte will have archegonium, which contains eggs and antheridium, which contains sperm. Once there is enough water on the gametophyte, the sperm will use the water to swim up a channel in the archegonium and to the egg. Fertilization will occur forming an embryo on the gametophyte which will grow into a sporophyte still attatched to the gametophyte. When the sporophyte matures it will become independent of the gametophyte and start all over.
The sori on the underside of a fern's leaf
The sori on the underside of a fern's leaf
(MDS) [2]


If you look more closely at the embryo, you would notice specialized placental transfer cells which are also often found in the respective maternal tissue. These cells aid the transfer of nutrients from the parent to the embryo through specialized ingrowths of the plasma membrane and cell wall. This structure can be compared to the function the umbilical cord serves between a human mother and her embryo. This multicellular embryo of land plants is not only unique; it is significant enough that this derived trait gives land plants the name embryophytes. (6) (PS)
Embyro of Fern
Embyro of Fern


Fern life cycle. [Source: http://www.sciencelearn.org.nz/Contexts/Ferns/Sci-Media/Animations-and-Interactives/Fern-life-cycle] (DM)

Growth and Development

Once the sporophyte reaches maturation it must recieve it's nutrients independently of the gametophyte. At this stage the fern must rely on its vascular system to receive it's enegy and nutrients in order to survive.


The fern seed contains an outer integument and megasporangial wall, which act as protection to the growing embryonic plant. The seeds can have between 1-3 integument layers depending on the fern. (11)(BB-V)

The epidermis the integument of young ferns and the covering material of its leaves. The epidermis is one cell thick. When the fern grows, the epidermis becomes the periderm, whic in turn becomes the bark of the tree. (20) (BS)


Ferns cannot move since they are plants. The only movement that occurs for a fern is the movement of sperm to the archegonium in early stages of reproduction, and the movement of nutrients throughout the plant's system.
[[http://www.biologie.uni-hamburg.de/b-online/library/webb/BOT311/FERNS/fern_reproductive_cycle.htm|[3] ]]

Sensing the Environment

Plants such as the fern do not have a nervous system like some animals do, but they can still sense and respond to their environment. For example, tropism, a directional response to a directional stimulus affects plants. A common example of this is phototropism, in which the stems grow towards light. This is caused by a differential growth of the stem. The cells on the stem surface have cells with blue-light receptors called phototropins. When the phototropins are stimulated by the corresponding wave of light, they induce growth, causing the plants to grow towards the light. (13) (AA)

Gas Exchange

Gas exchange occurs through transpiration. Carbon dioxide from the atmosphere will diffuse into leaves through openings called stomata and oxygen will diffuse out into the air through these same openings. In roots and stems this gas exchange occurs in lenticels.

A large surface area is required for gas exchange. Therefore, ferns utilize their spongy mesophyll, which is a collection of loosely arranged cells that create air spaces to increase surface area to volume ratio in order to facilitate gas exchange (3). The spongy mesophyll is covered by the cuticle, which is a water impermeable layer that contains scattered stomata. These strategies minimize desiccation - the process of becoming dried out (4) - but do not completely eliminate it.(5) (JLev)

Waste Removal

Ferns, like most plants, can get rid of water through a process called transpiration. Water vapor diffuses from the intracellular spaces of the leaves and through the stomata to the outside air. During photosynthesis oxygen is created and is not needed by the plant so it is known as a waste product. Plants give off the unneeded oxygen through transpiration as well.

Environmental Physiology

Ferns prefer areas with a great deal of sun exposure, rainfall, and high humidity, correlating to tropical and subtropical biomes. Such conditions must be kept daily as ferns are in need of constant moisture. The optimal growing temperature for a fern during the day is 72 F, and 60 F around night. The conditions for ferns vary among subspecies. (AC) [4]

Ferns, need a lot of moisture to survive, but they also need wind protection, as they are not very strong. Additionally, most ferns would not survive through a frost, so warmer temperatures are required. Finally, ferns survive in constant weather conditions! (19) (ES)

Internal Circulation

The transport system in ferns is that of the transport system in vascular plants. In the vascular system, two main tissues (bundles of similar cells) xylem and phloem conduct the pathways that distribute materials throughout the various parts of the plants. The xylem transport water and minerals from the roots of the fern upwards to the leaves while the phloem transport photosynthetic substances (food made from photosynthesis) from the leaves to the other organs. The xylem and phloem often flow in opposite directions. [8] (AY)

external image xylem1%5B1%5D.gif[5] (FZ)

Chemical Control

Review Questions

1. What are the two primary tissues involved in the internal circulation of ferns, and what are each of those tissues' roles in the process. (BH)
2. What is the role of sporophytes in the reproduction of ferns?(WSS)
3. What happens to the nutrients that ferns attain and how are the wastes removed? (JLau)


1. Hillis, David M. Principles of Life. Sunderland, MA: Sinauer Associates, 2012. Print
2. "Licorice Fern." Polypodium Glycyrrhiza. N.p., n.d. Web. 09 Dec. 2012.
3. http://www.uic.edu/classes/bios/bios100/lecturesf04am/lect11.htm
4. http://dictionary.reference.com/browse/desiccation?s=t
5. http://employees.csbsju.edu/ssaupe/biol327/lecture/transpiration.htm
6. Campbell, Neil A. and Jane B. Reece. 2008. Biology: Eighth Edition. Pearson Benjamin Cummings, San Francisco, California, USA.
7. http://www.biologyreference.com/Po-Re/Pteridophytes.html#b
8. http://www.wisegeek.com/what-are-vascular-plants.htm
9. http://science.jrank.org/pages/2689/Ferns-Importance-humans.html
10. https://www.cambridge.org/aus/catalogue/catalogue.asp?isbn=9780521728201&ss=exc
11. http://comenius.susqu.edu/biol/202/archaeplastida/viridiplantae/gymnosperms/pteridospermophyta/pteridospermophyta.htm
12."Ferns and Allies (Seedless Vascular Plants)." N.p., n.d. Web. 13 Dec. 2012. <www.austincc.edu/sziser/Biol%201409/.../Ferns%20and%20Allies.pdf>.
13. Hangarter, Roger P. "Plants In Motion." Plants In Motion. Indiana University, n.d. Web. 15 Dec. 2012.
15. http://bioweb.uwlax.edu/bio203/2011/korger_alex/geography.htm
18. http://fcit.usf.edu/florida/teacher/science/mod1/fern.html

19. http://www.aboutferns.com/what_is_a_fern.shtml

20. http://science.jrank.org/pages/3625/Integumentary-System-Plant-integumentary-system.html
21. http://www.yourlocalweb.co.uk/worcestershire/great-malvern/pictures/page2/
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