520 Retrospective Criticism. 



" 570. Soiving seeds in powdered charcoal has been tried in the Botanic 

 Garden at Munich with extraordinary success. Seeds of cucumbers and 

 melons sown in it germinated one day sooner than others sown in soil, and 

 plunged in the same hotbed ; becoming strong plants, while the others re- 

 mained comparatively stationary. Ferns sown on the surface of fine sifted 

 charcoal germinate quickly and vigorously; and it seems not improbable, that 

 this material may be found as useful in exciting seeds difficult to germinate, 

 as it is in rooting cuttings difficult to strike. 



" 571. Solving seeds in snoiv. This practice originated at Munich five or 

 six years ago,- and an account of it was given by M. Lucas in the Garten 

 Zeitung for 1841, and translated in the Gardener's Magazine for the same 

 year." 



According to Liebig, ammonia hastens and strengthens germination; and, 

 according to the same authority, charcoal and snow absorb ammonia from the 

 atmosphere ; this may be great part of the benefit. 



" 575. Selecting the shoot. The wood of the present or of the past year is 

 almost invariably chosen for cuttings. In the case of plants which are not 

 difficult to strike, a portion of the young shoot is cut off at any convenient 

 distance from the branch from which it proceeded, and of such a length as 

 may be considered most convenient for forming a plant. Thus in the case of 

 willows, gooseberries, currants, &c, from 9 in. to 18 in. are considered a 

 suitable length ; and the points of the shoots of these and other kinds of 

 easily-rooting plants are cut off, as not being sufficiently ripened to have 

 strong buds, or as containing too many small buds. In plants somewhat 

 difficult to strike, lateral shoots are chosen, and these are often drawn or 

 ' slipped ' out of the wood, so as to carry with them the axillary formation 

 of the bud and the vessels of the leaf," &c. 



The plexus of vessels at the heel of the shoot, or insertion of the branch in 

 the stem, causes a peculiar activity of life there ; and both buds and roots are 

 much more easily formed and in greater quantity there than in any other 

 place of the shoot. The insertion of the branch resembles, in this respect, the 

 collar of the stem. (577.) If the heel of the gooseberry or currant cutting is 

 taken out completely by breaking off, not cutting, it is better than taking off a 

 piece of the old wood. 



" 578. The time of taking off cuttings depends much on the nature of the 

 plant to be propagated," &c. 



Cuttings of growing succulent wood have vitality most active, and strike 

 root most quickly ; but, from the unripened state of the wood, are most apt to 

 die, and require to be kept more close and moist. There is danger in both 

 extremes, and both must be guarded against in such as are difficult to strike. 



" 580. The number of leaves which are left upon the cutting." When the 

 season is hot and warm, and little time to attend to keeping moist, succulent 

 cuttings, such as pinks, are most certain to strike, by paring close below the 

 uppermost joint, and cutting off above close to the joint, leaving none of the 

 leaves uncut, except those beginning to develope. Such a cutting is a mere 

 joint in a vital active, not ripened, state, and will stand a great deal of heat ; 

 if covered with a hand-glass in sunny weather, or in a hotbed frame in cold 

 weather, they seldom or never fail. Excitement of heat, not preservation, is 

 all that is wanted. 



"581. The lower ends of stout cuttings of plants somewhat difficult to 

 strike, such as the orange, are sometimes cut directly across, so as to rest on 

 the bottom of the pot, and sometimes they are, in addition, split up for an inch 

 or two, and the wound kept open with a wedge. This has been found by 

 long experience greatly to facilitate the rooting of such cuttings, probably by 

 increasing the surface by which absorption of moisture takes place, and at the 

 same time insuring only a moderate supply of moisture ; and perhaps, creating 

 a greater demand for the action of the leaves to cicatrise the wound with 

 granulous matter." 



When cuttings are tardy to strike, and have callosities formed, heat has a 



