. Outlines of botany for the high school laboratory and classroom (based on Gray's Lessons in botany) Prepared at the request of the Botanical Dept. of Harvard University. Botany; Botany. -i'A THE FVriT tlie Clematis aehene (Fiy. 2til), anil the tufted pappus in the case of the Dandelion (Fig- 263). The wing of the Maple key does not avail to carry the seed very far from the source, on the a,verage, as may he seen if we examine tlie neighhorliood of a ^laple tree when the seed- lings are coming up in the spring. Tlie seedlings are very numerous near the j^fii'tnt, very few at a distance of two
. Outlines of botany for the high school laboratory and classroom (based on Gray's Lessons in botany) Prepared at the request of the Botanical Dept. of Harvard University. Botany; Botany. -i'A THE FVriT tlie Clematis aehene (Fiy. 2til), anil the tufted pappus in the case of the Dandelion (Fig- 263). The wing of the Maple key does not avail to carry the seed very far from the source, on the a,verage, as may he seen if we examine tlie neighhorliood of a ^laple tree when the seed- lings are coming up in the spring. Tlie seedlings are very numerous near the j^fii'tnt, very few at a distance of two or three times the height of the tree. ISut one can- not fail to he struck with the successfid planting of the seeds. Although not originally covered by the soil, they stand in multitudes, rooted and growing, in spots wliere the grass was beaten down and matted befcu'c the fruits fell. Though bulky, the keys find their way into the grass through the aclion of tlie winds in driving the wings this M'ay and that, until the seed ends have been ^A'orked ^\•ell toward the moist sur- face of the soil. This example illustrates the fact, of common occurrence, that appendages of the fruit may serve both in dis- semination and in placing the seed in the position most likely to secure germination. 341. Tn connecition with this suliject, tin; luechaiiism of Kro- dium ( Fig. 271:1) for l)urying the fruit be mentioned. The elongated extremity of the fruit is hygrosi'opic ; that is, it absorbs vapor of water ra[)idly in damp weather, and exhales it in dry, the changes being accompanied by twistings and untwistings. As the fruit naturally falls with its weightier or seed end toward the earth, these hygroscopic movements, aided by backward-pointing Jiairs, cnalilc it to work its way through grass or other impediments toward the soil, and finally even partially to bury itself,. T,'.y Fruit of Erodium. On the left a sitigle ofir[)('l in damp ^veather; at the rip:ht, several car- pels in t
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectbotany, bookyear1901
