264 



ON PROPAGATION BY CUTTINGS. 



porous substances, of absorbing gases, an5 especially carbonic acid gas, to 

 the amount of many times their own bulk. Of all these, charcoal is one of 

 the most powerful in this respect, and it has been found that many plants 

 may be grown in powdered charcoal, if sufficiently supplied with w^ater, 

 more luxuriantly than in any other soil. The charcoal itself undergoes no 

 change, but it absorbs carbonic acid gas from the air ; this is dissolved by 

 the water, which is taken up by the roots, and thus it is introduced into the 

 system. In such cases the plant derives its solid matter as completely from 

 the atmosphere alone as if its roots were entirely exposed to it, for not a 

 particle of the charcoal is dissolved ; and it, therefore, affiDrds no nutriment 

 to the plants." ( Vegetable Physiology^ in a Popular Cyc. of Nat. Science^ 

 p. 117.) In the Gardeners Magazine lists will be found of cuttings of a 

 great many different species which had rooted in charcoal much sooner than 

 they usually do in sand or soil ; and from the most recent accounts it appears 

 that the practice is still carried on in Germany with success. "We would 

 therefore strongly recommend its introduction into British gardens. 



604. Propagation by joints and nodules. This mode of propagation is 

 founded on the principle, that every bud, whether visible or adventitious, 

 is capable of being made to produce a plant ; and it only differs from pro- 

 pagating by cuttings, in the buds or joints being taken off the plant with 

 a smaller quantity of nutritive matter attached to them. Plants are also 

 propagated by inserting the buds under the bark of other plants ; but this 

 mode, which is called budding, wUl form the subject of a separate section. 

 As bulbs are only buds, nature may be said to employ this mode of propa- 

 gation in the case of some species of bulb-bearing plants, such as JUium 

 and Z/ilium, in which the buds frequently drop from the stems on the soil, 

 and root into it. All the offsets of bulbs are of course buds, and may be 

 employed in propagation ; the nutriment to the young plant being supplied 

 from the scales, which eventually elongate into leaves, and the roots pro- 

 ceeding from the plate or base to which these scales are attached. The buds, 

 with the exception of bulbs, which are taken from the stems, branches, or 

 roots of plants, for the purpose of being rooted in the soil, always contain 

 a portion of the stem or root, to supply them with nourishment till they 

 are able, by the roots they form, to abstract it from the soil. In the case of 

 the vine, a joint is commonly taken; but in that of the potato, a single bud, 

 with a portion of the underground stem or tuber attached, is found sufficient. 

 There are very few plants, besides the vine and the potato, which are at 

 present propagated by rooting buds or joints in the soil, though there can 

 be no doubt that this mode is applicable to a great number of plants with 

 which it has not yet been tried. It is probable, also, that all or many 

 of those plants which can be propagated by cuttings of the roots might be 

 increased by small portions of these, so short as to be considered more in 

 the nature of joints than cuttings. For example, root-cuttings of the 

 common thorn and sea-kale are commonly made of several inches in length ; 

 and it is known that, if they are laid down lengthwise, and covered with 

 an inch of soil, they will produce roots at one end of the cutting and shoots 

 at the other. Now, by shortening the cutting to an inch, or half an inch, 

 and treating it in the same manner, it is probable the same result would 

 take place, though the plants produced might be weaker. It is true this 

 would be nothing more than propagating by very short cuttings ; but rooting 

 plants from joints may be so designated. The advantage of propagating by 



