. A text-book of botany for secondary schools. Botany. PERNS isr derive no nourishment from tliem (§ 41). This habit be- longs chiefly to the moist tropics, where plants may obtain sufficient moisture from the air without sending roots into the soil. 108. Sporophytes.—If an ordinary fern be examined, it will be discovered that it has a horizontal underground stem or rootstock (§ 27), ^\liich sends out roots into the soil, and one or more large leaves into the air (Fig. 179). These leaves. appearing to come directly from the soil, were once supposed to be different from ordinary leaves and were
. A text-book of botany for secondary schools. Botany. PERNS isr derive no nourishment from tliem (§ 41). This habit be- longs chiefly to the moist tropics, where plants may obtain sufficient moisture from the air without sending roots into the soil. 108. Sporophytes.—If an ordinary fern be examined, it will be discovered that it has a horizontal underground stem or rootstock (§ 27), ^\liich sends out roots into the soil, and one or more large leaves into the air (Fig. 179). These leaves. appearing to come directly from the soil, were once supposed to be different from ordinary leaves and were called frotuls ; but al- though the name is still used in connection with fern lea^-es, it is neither nec- essary nor ac- curate. These leaves are usu- ally compound, branchingeith- er pinnately or palmately. There are two peculiari- ties about fern leaves that should be noted. One is that in expanding the leaves seem to unroll from the base, as though they had been rolled from the apex downward, the apex being in the center of the roll. AVhen unrolling, this gives the leaves a crozier-like tip (Fig. 179). The other pecuharity is that the veins fork repeatedly (Fig. 180). This combination of unrolling leaves and forking veins is very characteristic of ferns. Probably the most important fact about the fern body. Fig. 179.—The habit of an ordinary fern (sporophyte), showing the horizontal rootstock sending out roots and leaves, and also the peculiar rolled tip of the developing 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
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectbotany, bookyear1906
