. Plant studies; an elementary botany. Botany. 296 PLANT STUDIES reduction of the exposed surface may be accurately regu- lated to suit the need (see §38). 139. Reduced leaves.—In regions tliat are rather per- manently dry, it is observed that the plants in general pro- duce smaller leaves than in other regions (see Fig. 173). That this holds a direct relation to the dry conditions is. Yiv. 173. Leaves from t lie common bass^vood (7^(7/(0. fallowing the effect of environ- ment; those at the right being from a tree growing in a river bottom (meaophyte conditions) ; those at the left being from
. Plant studies; an elementary botany. Botany. 296 PLANT STUDIES reduction of the exposed surface may be accurately regu- lated to suit the need (see §38). 139. Reduced leaves.—In regions tliat are rather per- manently dry, it is observed that the plants in general pro- duce smaller leaves than in other regions (see Fig. 173). That this holds a direct relation to the dry conditions is. Yiv. 173. Leaves from t lie common bass^vood (7^(7/(0. fallowing the effect of environ- ment; those at the right being from a tree growing in a river bottom (meaophyte conditions) ; those at the left being from a tree growing upon a dune, where it is exposed to intense light, heat, cold, and wind. Not only are the former larger, but they are much thinner. The leaves from the dune tree are strikingly smaller, much thicker, and more compact.—After Cowles. evident from the fact that the same i>lant often jiroduces smaller leaves in xerophytic conditions than in moist con- ditions. One of tlie most striking features of an arid region is the abseiK'O of large, showy leaves (see Fig. 172). These reduced loaves are (jf various forms, such as the needle leaves of pines, or tlie tlircad-likc^ leaves of certain sedges and grasses, or the nari'nw leaves "witli inrolled margins such as is common in many heath plants. The. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Coulter, John Merle, 1851-1928. New York, D. Appleton and Company
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