Biology/Ecology

Feeding Type

This category refers to the basic way by which an organism obtains its food/energy for metabolism.

A photoautotroph makes its own food (organic carbon compounds) using carbon dioxide and energy from the sun.
A heterotroph obtains its food/organic carbon compounds from the environment (e.g. by eating other organisms or remnants of organisms).
A mycoheterotroph is a special type of heterotroph, which obtains its organic carbon compounds from fungi. This term is used for plants that have parasitic mycorrhizal associations with fungi (the plants derive their nutrients from fungi and the fungi generally receive nothing in return).

Note: for some organisms the feeding type may differ depending on the life cycle stage. In these cases, a dash is used to show which feeding type is associated with which life cycle stage or type of organism. For example, there are some plants, such as Dendrolycopodium dendroideum, that are mycoheterotrophs in the gametophyte stage but are photoautotrophs in the sporophyte stage. In this example, the feeding type would be listed as: Photoautotroph–sporophyte, Mycoheterotroph–gametophyte.

Other organisms may utilize more than one feeding type, but the different feeding types can’t be clearly assigned to distinct life cycle stages. In this case, all of the feeding types used by the organism are simply listed. For example, some plants, such as Comandra umbellata, make their own food via photosynthesis, but also obtain some of their food by parasitizing other plants. The feeding type for this organism is listed as: Photoautotroph, Heterotroph.

The following sources were consulted for this data category:

Dyer, B.D. 2003. A Field Guide to Bacteria. Cornstalk Publishing Associates (Cornell University Press). Ithaca, NY. 355 pages.
Leake, J.R. 1994. Tansley Review No. 69. The biology of myco-heterotrophic (‘saprophytic’) plants. New Phytol. 127: 171-216.
Nickrent, D. 2015. The Parasitic Plant Connection website. The Strange and Wonderful Mycoheterotrophs webpage. 2015. Last updated 30-July-15. Department of Plant Biology, Southern Illinois University Carbondale. Available from: http://parasiticplants.siu.edu/Mycotrophs/Mycotrophs.html.

Feeding Group

Other Ecological Roles

Type of Reproduction

Number of Mating Types/Unique Gametes

Names of Mating Types/Gametes

Sex Determination

Reproductive Organization

Type of Spores/Gametophytes

As part of a plant’s life cycle, haploid spores are produced by diploid plants (sporophytes). The spores germinate to give rise to haploid plants called gametophytes. The gametophytes have specialized structures that produce sperm and eggs. In some species, the gametophytes are bisexual (they have male and female structures on the same plant) in other species, the gametophytes are unisexual (male or female). Whether the gametophytes of a vascular plant are unisexual or bisexual normally depends on the type of spore that is produced as described below.

Species of vascular plants that have one type of spore (homosporous plants) produce bisexual gametophytes.
In species of vascular plants that have two types of spores (heterosporous plants), one type, known as the megaspore, is much larger than the other and gives rise to a female plant (called a megagametophyte). The other type of spore, the microspore, is much smaller and germinates to form a male plant (called a microgametophtye). As their names would suggest, megagametophytes tend to be larger than microgametophytes.

Horsetails (Equisetum species) are an exception — they produce one type of spore, which may give rise to male gametophytes or female gametophytes. And, if the eggs of a female gametophyte are not fertilized within a certain period of time, the female gametophyte will grow male structures, becoming bisexual (Duckett, 1970).

Data were obtained from the following sources:

Duckett, J. G. (1970), Sexual behaviour of the genus Equisetum, subgenus Equisetum. Botanical Journal of the Linnean Society, 63: 327–352. doi:10.1111/j.1095-8339.1970.tb02311.x
Haines, A. 2003. The Families Huperziaceae and Lycopodiaceae of New England. A Taxonomic and Ecological Reference. V.F. Thomas Co. Bowdoin, ME. 100 pages.
Johri, B.M. and P.S. Srivastava (eds). 2001. Reproductive Biology of Plants. Narosa Publishing House.
Niklas, K.J. 1997. The evolutionary biology of Plants. The University of Chicago Press. Chicago.
Raven, P.H., R.F. Evert, and S.E. Eichhorn. 1992. Biology of Plants, Fifth edition. Worth Publishers.New York. 791 pages.