. Essentials of biology presented in problems. Biology. some of our worst weeds in this way. The burdock and clotbur are famihar examples. In both the mass of httle hooks is all that re- mains of an involucre. Thus the whole fruit cluster may be carried about and seeds scattered. In many of the Com- posites, as in the cockleburs and beg- gar's-ticks, the fruits are provided with strong curved projections which bear The coekiebur. Note the curved many Smaller hooklike barbs. ^°^^- 'Pappus. — Probably the most im- portant adaptations for dispersal of seeds are those by which the fruit is fitted
. Essentials of biology presented in problems. Biology. some of our worst weeds in this way. The burdock and clotbur are famihar examples. In both the mass of httle hooks is all that re- mains of an involucre. Thus the whole fruit cluster may be carried about and seeds scattered. In many of the Com- posites, as in the cockleburs and beg- gar's-ticks, the fruits are provided with strong curved projections which bear The coekiebur. Note the curved many Smaller hooklike barbs. ^°^^- 'Pappus. — Probably the most im- portant adaptations for dispersal of seeds are those by which the fruit is fitted for dispersal by the wind. That much-loved and much-hated weed, the dandelion, gives us an example of a plant in which the whole fruit is carried by the wind. The parachute, or pappus, is an outgrowth of the ovary wall. Many other fruits, notably that of the Canada thistle, are provided with the pap- pus as a means of getting away. In the milkweed the seeds have developed a silky outgrowth which may carry them for miles. In New York city the air is sometimes full of the down from these seeds, which is brought from far over the meadows of New Jer- sey by the prevailing westerly wind. Dehiscent Fruits and how they Scatter Seeds. — One of the many meth- ods of getting rid of seeds is seen in dry fruits. These simply split to allow of the escape of the seeds. Examples of common fruits that split open (dehiscent) are seen. DandeHon heads; the middle one a mass of ripe fruits ready to be scattered by the wind. Photo- graphed by 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 Hunter, George William, 1873-1948. New York, Cincinnati [etc. ] American Book Company
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectbiology, bookyear1911
