Vol. XXIII. No. 7.] 



POPULAR SCTEl^CE NEWS. 



103 



^onje, Barnj, aijd Gardeij. 



VEGETABLES AND FRUITS. 



Among the infinite variety of forms into 

 which the diflerent parts and organs of plants 

 are developed, we find some of our choicest 

 and most valuable food products. The leaves 

 of many plants, like the lettuce, chicory, 

 dandelion, parsley, etc., are largely consumed 

 as salad or cooked as "greens." In celery, 

 we do not eat the leaf, but an abnormally 

 thickened petiole, or leaf-stalk, and asparagus 

 heads are the young shoots, gathered before 

 they develop into branches. 



It is highly necessary for the preservation 

 of a plant that its seeds should be spread 

 widely over the ground, and we find that the 

 fully developed seeds of many plants are sur- 

 rounded by a pericarp of substances attrac- 

 tive and palatable to animals. In the apple 

 and quince, the calyx leaves and receptacle 

 become altered and fleshy, to form the edible 

 part of the fruit. The strawberry is not a true 

 berry at all, for the fruit is not a ripened pistil, 

 but an enlarged and fleshy receptacle, or ex- 

 tremity of the flower-stalk, thickly dotted over 

 with the minute ripened ovaries containing the 

 seed, and usually mistaken for the seeds them- 

 selves. The fig, also, consists of such an en- 

 larged receptacle, but it has been, as it were, 

 turned inside out, and the seed-like ovaries are 

 on the inside. A ripened rose-hip shows the 

 .same structure in a lesser degree. Mulberries 

 and pineapples consist of the ripened pro- 

 ducts of many flowers, placed on a common 

 receptacle, which is itself a part of the edible 

 mass. The Gaultheria, or chcckerberry, is 

 not a berry, but tlie thickened calyx of the 

 flower, which encloses a dry pod containing 

 the seed. 



The true berry is a permanently closed, 

 ripened, fleshy pistil, inclosing the seeds. 

 Familiar examples are the grape, currant, 

 and cranberry, as well as the orange, pump- 

 kin, and gourd. The peach, plum, etc., are 

 known as drupes, or stone-fruits, in which 

 the inner part' of the pericarp, or ripened 

 pistil, is hard and bone-like, enclosing the 

 seed, while outside of this is the fleshy edible 

 layer. The raspberry and blackberry are not 

 true berries, but are composed of a number of 

 little drupes, or drupelets, placed together 

 upon an elongated receptacle. In the rasp- 

 berry, the drupelets are readily detached from 

 the receptacle, but, in the blackberry, the 

 whole coheres strongly together, and the re- 

 ceptacle is eaten with the rest of the fruit. 

 A nut is a stone-fruit, or drupe, in which the 

 fleshy part is absent. The true seed is in- 

 closed within the shell, forming the edible 

 part. 



There are others plants in which the ripened 

 pistil opens at maturity, freeing the seeds 

 within. The pea and bean are familiar ex- 

 amples. The undeveloped seeds of the former 



delight our appetite as green peas, while the 

 unripened pistil and seeds of the bean arc 

 boiled together, and appear as "string beans." 



The modifications of roots also furnish 

 many valuable vegetables. Most of these, 

 however, are not true roots, but subterranean 

 stems, as is shown by the presence of buds, 

 or scars where buds have previously formed 

 and dropped off". The so-called roots of gin- 

 ger and sweet-flag are mereh' thickened por- 

 tions of a subterranean stem, called the 

 rhizoma, or root-stock. Tubers, like the 

 potato and Jerusalem artichoke, (which, by 

 the way, is not an artichoke, and did not 

 originate in Jerusalem), are the enlarged 

 buds of these subterranean branches, in which 

 a large proportion of starch has been depos- 

 ited. Examples of a similar tendency to 

 form tubers have been observed in the stems 

 of the potato-plant above the ground. 



A bulb, like the onion, is formed by the 

 enlargement of the leaves of an underground 

 stem, as shown by the scales or layers of 

 which it is composed. Solid bulbs, or corms, 

 are not true bulbs, but an enlarged under- 

 ground stem. In the turnip, beet, and radish, 

 the upper part of the root itself shares in the 

 enlargement, so that these vegetables are of a 

 compound nature. The object of these under- 

 ground enlargements is, evidently, to lay up a 

 store of nourishment for the plant during the 

 succeeding season. The cauliflower furnishes 

 an example of the use of the undeveloped 

 flowers of a plant as an article of food, and in 

 the true artichoke the thick, fleshy plant- 

 scales are utilized in the same manner. 



We have thus seen that there is hardly any 

 portion of a plant which may not be so modi- 

 fied .as to become food for man. We have 

 also seen that the strawberry, raspberry, and 

 blackberry are not really berries, but that the 

 squash and pumpkin are; while the potato, 

 onion, and flag-root are not true roots. These 

 are only a few of the interesting lessons taught 

 by the science of botany — a science not only 

 extremely fascinating in itself, but one which 

 requires no expensive apparatus for its study, 

 and for which every field, forest, and roadside 

 freely furnishes a profuse supply of material 

 for experiment and study. 



SILICA IN PLANTS. 



Silica is a more familiar term for silicic 

 acid, of which common sand is principally 

 composed. It is one of the most abundant 

 substances in nature, and forms a large pro- 

 portion of the earth's crust. It is also dis- 

 tinguished by its insoluble and refractory 

 character, all of the acids (except hydrofluo- 

 ric) having no action upon it, although when 

 melted with the caustic alkalies potash and 

 soda, it unites with them to form soluble 

 compounds. Strangely enough, there is a 

 modification or form of silicic acid which is 

 soluble in water, and this form often occurs 



in the waters of liot mineral springs ; but it 

 can only be artificially prepared in the labo- 

 ratory by a rather difficult process. 



And yet the delicate plant has the power to 

 dissolve this refractory substance as it occurs 

 in the earth, and incorporate it into its body. 

 The stems of the grasses and cereals are 

 strengthened by a very thin coating of silica, 

 regularly arranged in plates. Some of the 

 rushes, such as the Equisetum, or horse-tail 

 rush, contain so much silica that they are 

 used for scouring and polishing purposes. 



How the plant absorbs the silica from the 

 soil is a difficult matter to explain, although 

 it is no more wonderful than many other 

 chemical reactions which take place within 

 its cells. But in this connection we would 

 call attention to a form of fraud, which is 

 sometimes perpetrated upon farmers, where 

 artificial fertilizers are offered for sale con- 

 taining a large proportion of infusorial earth, 

 or finely divided silica, which, it is claimed, 

 is of great benefit to the growing plants bv 

 furnishing silica in a readily assimilable form. 

 In fact, every soil contains a superabundance 

 of this substance, and the process of assimila- 

 tion is a strictly chemical one ; no matter how 

 finely divided the silica may be, the plant 

 must first act upon it and render it soluble 

 before it can make use of it. P'armers will 

 do well to avoid all "silicated" fertilizers, and 

 spend no money for an element which is 

 abundantly present upon every farm in the 

 world. 



A BOTANICAL PUZZLE. 



A LITTLE greenish-yellow ffower grows 

 abundantly in New England, around old farm 

 houses, and, although originally introduced 

 from Europe, has, to some extent, escaped 

 from cultivation and become naturalized. It 

 is the Euphorbia Cyparissias, or cypress- 

 spurge, and is, apparently, one of the most 

 innocent and simply con.structed flowers im- 

 aginable, but in reality it is a snare and a de- 

 lusion to the amateur botanist, who is 

 extremely fortunate if he can analyze it by 

 any other method than the one so familiar to 

 students of "tracing liack." 



The flowers occur in umbel-like terminal 

 clusters, apparently composed of perfect flow- 

 ers, with calyx, corolla, stamens, and a central 

 pistil, but, in fact, this deceptive little blossom 

 is a compound flower, without calyx or 

 corolla, and entirely monujcious in its nature. 

 What seems to be the pLstil is a separate 

 flower, mounted on its own receptacle, and 

 represented by the pistil alone, while the cir- 

 cle of stamens surrounding it, also have each 

 a separate pedicel, or stalk, and are them- 

 selves distinct flowers, with all the organs 

 suppressed but a single stamen. The corolla 

 and calyx are nothing but an involucre of 

 bracts resembling petals and sepals, and, 

 taken altogether, the plant seems e.spocially 



