An elater is a

cell Cell most often refers to: * Cell (biology), the functional basic unit of life * Cellphone, a phone connected to a cellular network * Clandestine cell, a penetration-resistant form of a secret or outlawed organization * Electrochemical cell, a de ...

(or structure attached to a cell) that is

hygroscopic Hygroscopy is the phenomenon of attracting and holding water molecules via either absorption (chemistry), absorption or adsorption from the surrounding Natural environment, environment, which is usually at normal or room temperature. If water mol ...

, and therefore will change shape in response to changes in

moisture Moisture is the presence of a liquid, especially water, often in trace amounts. Moisture is defined as water in the adsorbed or absorbed phase. Small amounts of water may be found, for example, in the air (humidity), in foods, and in some comme ...

in the environment. Elaters come in a variety of forms, but are always associated with

plant Plants are the eukaryotes that form the Kingdom (biology), kingdom Plantae; they are predominantly Photosynthesis, photosynthetic. This means that they obtain their energy from sunlight, using chloroplasts derived from endosymbiosis with c ...

spore In biology, a spore is a unit of sexual reproduction, sexual (in fungi) or asexual reproduction that may be adapted for biological dispersal, dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores fo ...

s. In many plants that do not have seeds, they function in dispersing the spores to a new location.

Mosses Mosses are small, non-vascular flowerless plants in the taxonomic division Bryophyta (, ) '' sensu stricto''. Bryophyta ('' sensu lato'', Schimp. 1879) may also refer to the parent group bryophytes, which comprise liverworts, mosses, and ho ...

do not have elaters, but

peristome Peristome (from the Greek language, Greek ''peri'', meaning 'around' or 'about', and ''stoma'', 'mouth') is an anatomical feature that surrounds an opening to an organ or structure. Some plants, fungi, and shelled gastropods have peristomes. In mo ...

s which change shape with changes in humidity or moisture to allow for a gradual release of spores.

Horsetail elaters

In the

horsetail ''Equisetum'' (; horsetail) is the only living genus in Equisetaceae, a family of vascular plants that reproduce by spores rather than seeds. ''Equisetum'' is a "living fossil", the only living genus of the entire subclass Equisetidae, which ...

s, elaters are four ribbon-like appendages attached to the spores. These appendages develop from an outer spiral layer of the spore wall. At maturity, the four strips peel away from the inner wall, except at a single point on the spore where all four strips are attached. Under moist conditions, the elaters curl tightly around the spore. The wet spores tend to stick to each other and to nearby surfaces because of

surface tension Surface tension is the tendency of liquid surfaces at rest to shrink into the minimum surface area possible. Surface tension (physics), tension is what allows objects with a higher density than water such as razor blades and insects (e.g. Ge ...

. When conditions are dry, the spores no longer stick to each other and are more easily dispersed. At that time, the elaters uncoil to extend out from the spore and will catch air currents. The fact that they are extended only when conditions are dry means that successful spore dispersal is more likely.

Liverwort elaters

In the

liverwort Liverworts are a group of non-vascular land plants forming the division Marchantiophyta (). They may also be referred to as hepatics. Like mosses and hornworts, they have a gametophyte-dominant life cycle, in which cells of the plant carry ...

s, also known as Marchantiophyta xample ''Riccia'', ''Marchantia'' elaters are cells that develop in the

sporophyte A sporophyte () is one of the two alternation of generations, alternating multicellular organism, multicellular phases in the biological life cycle, life cycles of plants and algae. It is a diploid multicellular organism which produces asexual Spo ...

alongside the

s. They are complete cells, usually with helical thickenings at maturity that respond to moisture content. In most liverworts, the elaters are unattached, but in some leafy species (such as '' Frullania'') a few elaters will remain attached to the inside of the

sporangium A sporangium (from Late Latin, ; : sporangia) is an enclosure in which spores are formed. It can be composed of a unicellular organism, single cell or can be multicellular organism, multicellular. Virtually all plants, fungus, fungi, and many ot ...

(spore capsule). Ptilidium pulcherrimum Sporen

Hornwort pseudo-elaters

In the

hornwort Hornworts are a group of non-vascular Embryophytes (land plants) constituting the division Anthocerotophyta (). The common name refers to the elongated horn-like structure, which is the sporophyte. As in mosses and liverworts, hornworts have a ...

s, elaters are branched clusters of cells that develop in the

alongside the

s. They are complete cells, usually without helical thickenings (except in the

Dendrocerotaceae The Dendrocerotaceae is the only family of hornworts in the order Order, ORDER or Orders may refer to: * A socio-political or established or existing order, e.g. World order, Ancien Regime, Pax Britannica * Categorization, the process in w ...

References

* Bold, Harold C., Alexopoulos, Constantine J., & Delevoryas, Theodore. (1987). ''Morphology of Plants and Fungi'', (5th ed.). New York: Harper & Row. . * Campbell, Douglas Houghton. (1918). ''The Structure and Development of Mosses and Ferns'', (3rd ed.). New York: The Macmillan Company. * Kenrick, Paul & Crane, Peter R. (1997). ''The Origin and Early Diversification of Land Plants: A Cladistic Study''. Washington, D. C.: Smithsonian Institution Press. {{ISBN, 1-56098-730-8. * Smith, Gilbert M. (1938). ''Cryptogamic Botany, Volume II: Bryophytes and Pteridophytes''. New York: McGraw-Hill Book Company. Plant anatomy