The term "marcescent" is also used in mycology to describe a mushroom which (unlike most species, described as "putrescent") can dry out, but later revive and continue to disperse spores. Genus Marasmius is well-known for this feature, which was considered taxonomically important by Elias Magnus Fries in his 1838 classification of the fungi.
Benefits
In plants, marcescence is considered a juvenile characteristic because it is more common on younger trees and on the lower, more juvenile, parts of older trees. One possible advantage of marcescent leaves is that may deter feeding of large herbivores, such as deer and moose, which normally eat the twigs and their nutritious buds. Dead, dry leaves make the twigs less nutritious and less palatable.Marcescent leaves may protect some species from water stress or temperatures stress. For example, in tropical alpine environments a wide variety of plants in different plant families and different parts of the world have evolved a growth form known as the caulescent rosette, characterized by evergreen rosettes growing above marcescent leaves. Examples of plants for which the marcescent leaves have been confirmed to improve survival, help water balance, or protect the plant from cold injury are Espeletia schultzii and Espeletia timotensis, both from the Andes.
References
- Earl E. 1931. Marcescent leaves of certain species of Quercus. Botanical Gazette 92: 85-93.
- Hoshaw, R.W. and Guard, A.T. 1949. Abscission of marcescent leaves of Quercus palustris and Q. coccinea. Botanical Gazette 110: 587-593.
- Svendsen, Claus R. 2001. Effects of marcescent leaves on winter browsing by large herbivores in northern temperate deciduous forests. Alces 37(2): 475-482.
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Last updated on Saturday August 16, 2008 at 12:29:28 PDT (GMT -0700)
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