IRISH GARDENING 



^S7 



metabolism, calcium-oxolate crystals, resins and 

 alkaloids remain to be thrown off with the falling 

 leaves. 



In 1882, M.M. Guig-nard and Van Tieghem re- 

 turned to the study of Gymnocladus, but began their 

 investigation in the middle of June. They found that 

 no cork is tormed at the base of the leaflets. It is not 

 worth while to heal the wound on the leaf-stalk which 

 is itself to fall in a day or so. The suberised layer was 

 formed at the base of the main petiole by the middle 

 of June: then a layer of meristem, the " phellogen " 

 or cork cambium originates below it and the absciss- 

 layer above it, before the end of June. This layer 

 spreads inwards from the epidermis through the cell- 

 ular tissue of the bast and wood-bundles. It consists 

 not of two, but of three layers of cells of which the 

 middle row is absorbed. The two remaining rows, 

 still living and turgid, swell outwards with rounded 

 surfaces, and so create a strain which snaps the fibres 

 and vessels. These observers also induced leaf-fall 

 artificially at midsummer by placing a cut branch in a 

 box filled with moist air, and they found that after the 

 fall of the leaf the cellular tissue of the vascular 

 bundles whose ends are exposed on the leaf-scar 

 becomes " merismatic," i.e., undergoes cell division, 

 forms cork, and penetrates and fills up the ends of the 

 vessels. 



It is well to bear in mind that prolonged drought 

 will induce leaf-fall much as does a frost, and that a 

 layer of cork is formed below the prickles on old stems 

 of rose or bramble, and below twigs in some plants 

 which shed these branches as others shed their leaves. 

 On the other hand, if a branch be broken through 

 early in summer its leaves wither but do not fall, no 

 absciss-layer being formed. Coppiced oaks or the 

 clipped beeches or hornbeams in the hedges of nursery 

 gardens also retain their leaves, as if the energy and 

 material used up in the formation of callus to heal 

 the wounds caused by pruning-knife or shears left none 

 for the formation of the usual absciss-layers. The poll- 

 ard hornbeams of Epping Forest, which used to retain 

 their withered foliage through the winter, have, since 

 the Forest was taken over by the Corporation of 

 London, and lopping has been stopped, been gradually 

 regaining the deciduous character of " spear" trees. 



Everyone must have noticed the successive fall of the 

 leaflets and the leaf-stalks in the ash or horse-chestnut, 

 the thick-ended petioles being aptly known by children 

 as " bones," since they are by no means unlike the leg- 

 bones of birds. There is, however, another interesting 

 little point in connection with leaf-fall which is, perhaps, 

 less familiar, well illustrated in the photographs, by 

 Mr. Johnson, this is the order in which the leaves fall 

 from the twig. In the beech this is hasipetal, i.e., the 

 younger leaves at the apex of the twigs fall first. 

 In the linden, the poplar, and apparently in the 

 majority of trees the fall takes place acropetally, 

 i.e., the older leaves at the base of the twigs fall 

 first. 



It is well to notice that here again we have order and 

 not chance : that nature has, as we often find, two or 

 more ways of bringing about the same result ; and that 

 even in such an apparently simple matter as the fall of 

 the leaf there is room for a good deal more research. 



A Book on Bulbs 



ANEW work on bulb culture.* By such a skilful 

 compiler of books as Mr. John Weathers is 

 especially welcome at the present time. The 

 volume is a bulky one (471 pages), it contains 342 

 illustrations by the author, and is produced in the 

 excellent style that characterises all Mr. Murray's 

 publications. The book proper opens with descriptive 

 chapters on the structure and physiology of bulbs, 

 tubers, and other subterranean storage organs followed 

 by other chapters on the cultivation, propagation, 

 forcing, lifting, storage, &c., of "bulbous" garden 

 plants. The term " bulb" is meant to include not only 

 true bulbs, but tubers, corms, rhizomes, and similar 

 underground structures. The bulk of the book (pages 

 55 to 458) is devoted to descriptions of all the bulbous 

 plants commonly grown in gardens and arranged in 

 alphabetical order for convenience of reference. 



On page 32 is given a list of "bulbous" plants that 

 may be grown in the open garden. It contains about 

 ■75 genera; most of these will flourish in an\- well 

 drained soil if deeply dug or trenched and well 

 manured. Indeed, as the author points' out, some, like 

 tuberous sunflowers, doronicums, hemerocallis, &c. 

 will grow in any but the very worst sour and swampy 

 soil, so vigorous is the action of their roots. Advantage 

 may be taken of such coarse or free-growing plants to 

 improve soil that is generally regarded as poor and 

 infertile. They will find not only nourishment in it, but 

 owing to the action of their rapidly spreading roots 

 they bring about a much better condition of the 

 impoverished soil after a season or two of growth. 

 For true bulbous plants anything savouring of wet, 

 heavy, clayey soil is unsuitable. On page 34 is given 

 a list of 114 genera of "bulbous" plants that are 

 usually grown under glass, and each of these also are 

 fully described in the descriptive portion of the work. 

 We can confidently say that this is the most complete 

 work on bulbs from the point of view of the gardener 

 that is at present available to the general reader. 



•The "Bulb Book," by John Weathers. London: John Murr.-iy, 

 price 15s. 



Hollyhocks. 



The hollyhock is one of our most stately and pic- 

 turesque border plants, but unfortunately it is \e.vy sub- 

 ject to a peculiar " rust" caused by a parasitic fungus. 

 This disease is the cause of much harm, and seriously 

 interferes with its more general cultivation. Holly- 

 hocks require a rich, deep soil, well drained and culti- 

 vated to enable them to form those glorious tall spikes 

 of flowers so familiar to all of us. The usual method of 

 raising hollyhocks is by seeds. These are sown thinly 

 in June or July in drills one foot apart. The seedlings 

 are left until the following spring, when they may be 

 transplanted to their permanent quarters in the border. 

 In cold, wet districts the seeds are sown in pans or 

 boxes, and the seedlings afterwards transferred to pots 

 and wintered in a cold frame until planting-out time. 

 Hollyhocks require attention during growth. The soil 

 must be kept hoed and mulched with half-rotten manure 

 and the plants watered if the season is very dry. 



