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Talks Afield About Plants And The Science Of Plants;
Talks Afield About Plants And The Science Of Plants Author:Liberty Hyde Bailey Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: alous. When all the sepals, all the petals, all the stamens, and all the pistils are alike, the flower is regular; when any or all of them are unlike, as in the ... more »pea and bean, or when a gamopetalous corolla is not equally lobed, as in the mint, it is irregular. In this connection it remains but to be said that flowers vary as widely in size and in appearance as they do in essential structure. The smallest of flowers is that of the little Wolffia which floats on ponds throughout most of the Northern States, the entire plant being smaller than an ordinary pin- head. The largest flower is that of the Raf- flesia, a parasitic plant of the Javan forests. They are sometimes over a yard across. Many flowers possess no colors other than green. The flowers of our grasses and cereal grains are green and usually inconspicuous, and the same may be said of the flowers of most forest trees. The manner in which the stems of flowering plants increase in diameter must next demand our attention. There are two general methods by which this increase takes place. If we cut off a corn-stalk (Fig. 43) we observe that there are many threads running through it lengthwise. A cross-sectionof the truuk of a palm would reveal a similar structure. Contrast with these stems a cross-section of an oak, as shown in Fig. 44. In this section there are conspicuous layers or rings of wood; the internal threads are not to be seen. The corn-stalk and the trunk of the palm increase in diameter by the addition in the interior of new threads which stretch out the surface of the stalk. These plants are inside growers or endogens. Fig. 43. Fig. 44. The trunk of the oak increases in diameter by the addition of new wood in layers near its surface. It is, therefore, an outside grower, or an exogen. In the Northern Un...« less