41 



mean higher high tide The average height of the higher of two 

 unequal daily high tides over 19 years. 



mean low water The average height of the low water over 19 

 years. 



mean lower low water The average height of the lower of two 

 unequal daily low tides over 19 years. 



mean tide level A plane midway between mean high water and 

 mean low water. 



mesohaline Term to characterize waters with salinity of 5 to 

 187m, due to ocean-derived salts. 



mesophyte, mesophytic Any plant growing where moisture and 

 aeration conditions lie between extremes. (Plants typically found 

 in habitats with average moisture conditions, not usually dry 

 or wet.) 



mesosaline Term to characterize waters with salinity of 5 to 

 187™, due to land-derived salts. 



mineral soil Soil composed of predominantly mineral rather than 

 organic materials (see page 44). 



mixohaline Term to characterize water with salinity of 0.5 to 

 30°/oo, due to ocean salts. The term is roughly equivalent to 

 the term brackish. 



mixosaline Term to characterize waters with salinity of 0.5 to 

 307™, due to land-derived salts. 



mud Wet soft earth composed predominantly of clay and silt- 

 fine mineral sediments less than 0.074 mm in diameter (Black 

 1968; Liu 1970). 



needle-leaved deciduous Woody gymnosperms (trees or shrubs) 

 with needle-shaped or scale-like leaves that are shed during the 

 cold or dry season; e.g., bald cypress (Taxodium distichum). 



needle-leaved evergreen Woody gymnosperms with green, 

 needle-shaped, or scale-like leaves that are retained by plants 

 throughout the year; e.g., black spruce (Picea mariana). 



nonpersistent emergents Emergent hydrophytes whose leaves 

 and stems break down at the end of the growing season so that 

 most above-ground portions of the plants are easily transported 

 by currents, waves, or ice. The breakdown may result from nor- 

 mal decay or the physical force of strong waves or ice. At cer- 

 tain seasons of the year there are no visible traces of the plants 

 above the surface of the water; e.g., wild rice (Zizania aquatica), 

 arrow arum (Peltandra virginica). 



obligate hydrophytes Species that are found only in wetlands— 

 e.g., cattail (Typha latifolia) as opposed to ubiquitous species 

 that grow either in wetland or on upland— e.g., red maple (Acer 

 rubrum). 



oligohaline Term to characterize water with salinity of 0.5 to 

 5.0°/»o, due to ocean-derived salts. 



oligosaline Term to characterize water with salinity of 0.5 to 

 5.07™, due to land-derived salts. 



organic soil Soil composed of predominantly organic rather than 

 mineral material. Equivalent to Histosol (see page 44). 



persistent emergent Emergent hydrophytes that normally re- 

 main standing at least until the beginning of the next growing 

 season; e.g., cattails (Typha spp.) or bulrushes (Scirpus spp.). 



photic zone The upper water layer down to the depth of effec- 

 tive light penetration where photosynthesis balances respira- 



tion. This level (the compensation level) usually occurs at the 

 depth of 1% light penetration and forms the lower boundary 

 of the zone of net metabolic production. 



pioneer plants Herbaceous annual and seedling perennial plants 

 that colonize bare areas as a first stage in secondary succession. 



polyhaline Term to characterize water with salinity of 18 to 

 307m, due to ocean salts. 



polysaline Term to characterize water with salinity of 18 to 

 307 M , due to land-derived salts. 



saline General term for waters containing various dissolved salts. 

 We restrict the term to inland waters where the ratios of the 

 salts often vary; the term haline is applied to coastal waters 

 where the salts are roughly in the same proportion as found 

 in undiluted sea water (see page 25). 



salinity The total amount of solid material in grams contained 

 in 1 kg of water when all the carbonate has been converted to 

 oxide, the bromine and iodine replaced by chlorine, and all the 

 organic matter completely oxidized. 



sand Composed predominantly of coarse-grained mineral sedi- 

 ments with diameters larger than 0.074 mm (Black 1968) and 

 smaller than 2 mm (Liu 1970; Weber 1973). 



shrub A woody plant which at maturity is usually less than 6 

 m (20 feet) tall and generally exhibits several erect, spreading, 

 or prostrate stems and has a bushy appearance; e.g., speckled 

 alder (Alnus rugosa) or buttonbush (Cephalanthus occidentalis). 



sound A body of water that is usually broad, elongate, and 

 parallel to the shore between the mainland and one or more 

 islands. 



spring tide The highest high and lowest low tides during the 

 lunar month. 



stone Rock fragments larger than 25.4 cm (10 inches) but less 

 than 60.4 cm (24 inches). 



submergent plant A vascular or nonvascular hydrophyte, either 

 rooted or nonrooted, which lies entirely beneath the water sur- 

 face, except for flowering parts in some species; e.g., wild celery 

 (Vallisneria americana) or the stoneworts (Chara spp.). 



terrigenous Derived from or originating on the land (usually 

 referring to sediments) as opposed to material or sediments 

 produced in the ocean (marine) or as a result of biologic activity 

 (biogenous). 



tree A woody plant which at maturity is usually 6 m (20 feet) 

 or more in height and generally has a single trunk, unbranched 

 for 1 m or more above the ground, and a more or less definite 

 crown; e.g., red maple (Acer rubrum), northern white cedar 

 (Thuja occidentalis). 



water table The upper surface of a zone of saturation. No water 

 table exists where that surface is formed by an impermeable 

 body (Langbein and Iseri 1960:21). 



woody plant A seed plant (gymnosperm or angiosperm) that 

 develops persistent, hard, fibrous tissues, basically xylem; e.g., 

 trees and shrubs. 



xerophyte, xerophytic Any plant growing in a habitat in which 

 an appreciable portion of the rooting medium dries to the wilt- 

 ing coefficient at frequent intervals. (Plants typically found in 

 very dry habitats.) 



