894 



LAWSONIA 



' produ 



glubrous shnib, with branches spinv or not. Important 

 generic characters are : calyx 4-parted: petals 4: stamens 

 8: capsule globose, 4-celled, rupturing irregularly. 



&lba, Lam. Henna Plant. Lvs. opposite,"oval-lanceo- 

 late, entire, short-stalked : fls. panicled. Native to In- 

 dia, the Orient, N. Afr. Naturalized in West Indies. 



LAYERING. Figs. 1248-1253. Layering is the pro- 

 cess by which a part of a plant stem in i 

 roots while still attached to and notirWli 

 plant, so that it may be able to iii.iiniiiii n: umIc |,.'inlent 

 growth. The tendency, under l.i ,-ns, to 



produce roots from the cambium , ,. i |-;irt of 



the stem is manifested by many ].l:iiii , . -im . iilh in the 

 tropics. It may be noticed in the spitiis c.f Fi<us culti- 

 vated in the greenhouse, in Epigiea and if 7i us Toxicoden- 

 dron in the woods, in tomato vines in the garden, in 

 grape canes lying on the ground, and frequently in young 

 apple tr.-fs wlun tli.- trunk 1., r..iii,< .•,,v,]v,l with" earth 



ith 



those plants which du not ruul readily Iruiu cuttings. 



The mode of root-production is essentially the same 

 in either case. The right conditions as to moisture, 

 temperature, food supply, etc., seem to stimulate the 

 formation of one or more growing points in the cambium 

 zone. The multiplying cells force their way through the 

 bark, and if favorable soil contact is secured, supporting 

 roots are soon developed. The same results may come, 

 sometimes more readily, from or near a callus formed in 

 the effort to liial a cut surface. It is wln-n the food sup- 

 ply is dclici.iit ..r tic- cell artinn is s,. slow that the de- 

 tached |,art w.iul.l pcrM, l.ef.. re supporting roots could 

 be establislie.l, il,al r..,,tiin; wl,ile tlie parts are still at- 

 tached tu and nourished by the parent plant need be 

 employed. 



The different methods of Layering are simply matters 

 of detail adapted to the varying natures of the plants to 

 be dealt with. Usually branches are selected of rather 

 young wood, which can easily be brought under the soil 

 and which, when rooted, can be removed without damage 

 to the old plant. The most favorable season is generally 

 the spring or time of most rapid cell growth. 



1348 A layer nolUied at the 



METHODS cjp L.\YEKING 

 f lioired branch— 

 Bark ruptured. 

 Bark ringed. 

 Trees Axn I Tongue cut. 

 Shrubs 1 Tip Layered. 



Mound- or siool-layer. 

 I rotted or aerial layer. 

 Vivii-a AMn ( Ifimple laiirr. 

 Trench la,,,,: 

 [ Serpentine h, ,,,■,•. 



As shown in Fig. 1248. a suitable lir;iii. Ii i- 

 ground and held in place by a forked pi]i, -<■ 



Case 



LAYERING 



tion of it is covered with 2 or ."! inches of rich earth, the 

 end being bent to an upright position and fastened to a 

 stake. The bend and consequent rupture of the bark 

 may be all that is needed to obstruct the movement of 

 food-material and cause the development of roots at this 



point. If not, a tongue may be cut not deeper than one- 

 third of the thickness of the branch from below upwards 

 and near a bud or node. In Fig. 1249 a layered branch 

 is shown with a ring of bark removed, a good practice 

 with thick, hard-barked species. 



For many low-branched shrubs, mound- or stool-layers 

 are prepared (Fig. 1250), as follows: In the spring, head 

 the bush back to a series of stubs, which will produce a 

 large number of vigorous young shoots. By midsummer, 

 in some cases, or the following spring, a niound of earth 

 is thrown around the old stool and the base of the new 

 shoots, and from these latter abundant rooting is se- 

 cured, so that by the following autumn or spring they 

 may be separated and set in nursery rows. 



When a branch cannot be brought to the ground, 

 sometimes the earth is brought to the branch by clasp- 

 ing the halves of a broken or specially made pot arotind 

 a tongued or girdled branch and filling in earth and 

 sphagnum moss to retain the nmisturc; or the mie.s may 



1250. Mound 





In Fin 



.1 in tu the level of the dotted line. 

 -h'.wn wliat is often called the serpen- 

 tine layer, ni wbicli the cane is bent, portions being 

 covered and the intervals left above the ground. It is 

 said that by this means the tendency of the sap to flow 

 to the extremity and there make the strongest growth, 

 is overcome, and even rooting secured the whole length 

 of the cane. This method is often used with quick-grow- 

 ing vines like clematis and wistaria, from which it is 

 possible to secure a succession of layers from the an- 

 nual growth during spring and early summer. 



All of the foregoing operations will be found more 

 readily successful in the more moist situations ; more 

 MI ■! .vviul in the nearly saturated atmosphere of the 

 -"iith. rn states, for instance, than in the comparatively 

 dry conditions of the prairie states. g. c. Mason. 



