The Selaginellaceae

The Spike Moss Family

Selaginella	Selaginella Strobili

The Selaginellaceae family is comprised of a single genus, selaginella. Within this genus, there are approximately 700 species, distributed throughout the world in a wide range of habitats. They are mainly tropical, with a few species extending into arctic regions of both hemispheres.

Vegetative Characters | Reproductive Characters | Diagnostic Characters | Economic Importance/Fun Facts | Evolutionary Adaptations and Relationships | Glossary of Terms | References and Links | Pictures

Vegetative Characters

• mostly terrestrial, herbaceous, and perennial plants
• under 2 cm tall
• dichotomously branching stems and roots
• microphylls about 0.5-1 cm long, spirally arranged, with a single unbranched vein
• microphylls on the upper side of the stem are smaller than those on the lower side
• microphylls overlapping on stem
• ligule present on each microphyll
• shoot is flattened with distinct ventral and dorsal sides

Reproductive Characters

• heterosporous; megaspores = female, microspores = male
• terminal strobili
• sporangia borne in or near the axils of well-differentiated sporophylls, usually on 4-sided strobili
• strobili with either megasporangia, microsporangia or both
• megasporangia usually with 4 megaspores
• microsporangia usually with more than 100 microspores
• megagametophytes partly protruding from the megaspore wall
• microgametophytes developing wholly within the microspore, the wall rupturing to release the sperm

Diagnostic Characters

• dichotomously branching stems and roots
• distinct terminal strobili
• heterosporous
• microphylls overlapping on stem
• single unbranched vein in microphyll
• ligule present on each microphyll

Economic Importance/Fun Facts

• This family is not significant economically
• Sometimes used as ornamentals - also certain desert species are sold as novilties as ressurection ferns, as the dried plant opens up when rehydrated.

Evolutionary Adaptations and Relationships

• Selaginellaceae are related only distantly to the other lycopod families, Lycopodiaceae and Isoetaceae
• heterospory and ligulate leaves are potential synapomorphies lnking Selaginellaceae and Isoetaceae
• some authors (O. Kuntze 1891-1898, vol. 2, pp. 824-827; W. Rothmaler 1944) have segregated other gerera than just Selaginella based on generic concepts established by A. Palisot de Beauvois (1805, pp. 95-114) who recognized four genera
• A.F. Spring (1850) combined the four genera into the broadly defined genus Selaginella

Glossary of Terms

References and Links

• http://www.wisc.edu/botit/systematics/family_index/Family_Pages/Family_Pages_S/Selaginellaceae.html
• http://www.botany.hawaii.edu/faculty/carr/selaginell.htm
• http://www.anbg.gov.au/projects/fern/taxa/selaginellaceae.html
• http://www.science.siu.edu/landplants/Lycophyta/images/Selaginella.kraus.JPEG
• http://www.wisc.edu/botit/img/bot/401/Lycophyta_(Microphyllophyta)/Selaginellaceae/Selaginella/LS%20strobilus%20MC%20.jpg
• http://caliban.mpiz-koeln.mpg.de/~stueber/thome/band1/tafel_021_small.jpg
• http://www.wisc.edu/botit/img/bot/401/Lycophyta_(Microphyllophyta)/Selaginellaceae/Selaginella/Prep%20slide%20Strobilus%20ls%20MC%20.jpg
• http://www.wisc.edu/botit/img/bot/401/Lycophyta_(Microphyllophyta)/Selaginellaceae/Selaginella/Sporangia%20MC%20.jpg
• http://www.wisc.edu/botit/img/bot/401/Lycophyta_(Microphyllophyta)/Selaginellaceae/Selaginella/Strobilus%20With%20Lycopodium%20.jpg
• Judd et al., 1999. Plant Systematics: a phylogenetic approach. Sinauer Associates, Inc. Sunderland, MA U.S.A.
• Wagner, Warren H. Jr. and Joseph M Beitel, 1993. Flora of North America. Oxford University Press. New York, NY U.S.A.

Pictures

Selaginella selaginoides	Prep slide Strobilus

Selaginelladissected strobilus	Selaginella and Lycopodium strobili

For questions or feedback, contact: Kelly McKay