EARTH-^^EGETABLES 43 



term to designate those garden esculents of which the nutri- 

 tive part grows in the earth. This edible part may be either 

 a root-tuber as in the sweet potato (Figs. 56, 57), a crown-tuber 

 as in the beet, turnip, radish, carrot, and parsnip (Figs. 41- 

 55), or it may be a stem-tuber as in the white potato and 

 the Jerusalem artichoke (Figs. 59, I-IV), or a bulb as in the 

 onion (Figs. 60, 61). A root-tuber consists entirely of a 

 swollen root gorged with reserve food. A crown-tuber bears 

 a crown of leaves more or less rosette-hke, thus showing it- 

 self to be part stem and part root. By the term "tuber" 

 botanists sometimes mean only a stem-tuber, but the word 

 is more conveniently applied in a general sense to all short 

 and much thickened roots or stems. A stem-tuber differs from 

 a root-tuber in having "eyes" or buds regularly arranged in 

 little pits along the sides; and from a crown-tuber in bearing 

 no foliage-leaves, but instead minute appendages, one below 

 each eye. If a stem-tuber be made to sprout, the buds will 

 grow into leafy branches. A bulb differs from a tuber in 

 consisting chieflj' of readily separable scale-like parts or 

 layers which are mostly succulent. 



As 'nail be seen from the chemical chart (page 114) the 

 very large percentage of water in earth-vegetables presents 

 a striking contrast to what we find in grains, nuts, and pulse. 

 Notice also, particularly in the roots, the comparatively 



white or rose-colored and five in number; and finally, outside of all, a 

 row of sepals, which are green, and five in number. G. a twig bearing 

 three leaves and two fruits of which one is shedding its leathery husk. 

 H, a single fruit. J, the same, with half the husk removed, to show the 

 nut which appears above with half its shell removed to reveal the seed 

 within. E. the seed, covered by its thin brownish coat. F, the embryo 

 gorged with food, shown after removal of the seed-coat. All more or less 

 reduced in size. (Baillon.) — The plant is a tree closely resembling the 

 peach tree in general form and in every part except the fruit. The 

 flowers, appearing in very early spring, before the leaves, are re- 

 markably beautiful. The fruit of the almond closely resembles a 

 green peach; it differs from the peach mainly in ha-sdng in place of the 

 hard-shelled "stone" a rather ,soft-shelled nut which is covered by a 

 leathery husk that commonly splits open when ripe. 



pistil and stamens which are known as the •'essmtwl organs," and the sepals 

 which constitute the calyx or outer floral envelope, it has an inner envelope 

 made up of petals distinctly different in appearance from the sepals. The 

 petals taken together constitute what is called the corolla, or "little crown" 

 of the flower, and form commonly the most conspicuous part. The calyx 

 and corolla taken together are called the perianth, especially if they are 

 closely similar in appearance. 



