AN ENCYCLOPAEDIA OF HORTICULTURE. 



245 



LEAP - ROLLERS. By this name are denoted 

 the larvae of insects belonging to several different or- 

 ders, and all of which may cause considerable injury to 

 the trees and shrubs in gardens. To herbaceous plants 

 they are less hurtful. The larvae dwell in tubes, formed 

 of the inrolled leaves, and are thus well protected against 

 assaults from without. Many of them have the habit, 

 when the plant on which they live is smartly shaken, 

 of crawling from the leaf-tube, and lowering themselves, 

 by a thread of silk, till the dreaded danger is past, 

 when they pull themselves up by the thread, and re- 

 enter the tubes. Advantage may be taken of this habit 

 to shake them on to a sheet laid below; and from this 

 they can be collected for destruction. The leaf is re- 

 tained in an inrolled form by means of numerous short 

 cables of silk, passing from surface to surface of the 

 roll. Sometimes, the silk is fixed before the leaf has 

 opened originally; but, in other cases, the larvae have 

 been seen at work fixing the threads and drawing the 

 leaf into position. In the smaller proportion of cases, 

 the inrolling of the leaf is due to swelling on one sur- 

 face, brought about by the irritation caused by the 

 action of the indweller or indwellers. The damage 

 done may be confined to suction of the tissues in the 

 interior of the tube, or these parts may be eaten away, 

 and the leaf may thus be killed. The leading forms of 

 Leaf -rollers are : (1) Moths, for the most part belonging 

 to the group of Tortrices. The insects seldom reach 

 lin. in spread of wings ; but they are at times so numerous 

 as to more than make up for their small size individually. 

 Their wings are generally rather broad, and are usually 

 dark or some shade of brown. Some species almost strip 

 trees of their foliage, e.g., Tortrix viridana on Oaks. 

 (2) The leaves of several of the cultivated Willows have the 

 margins rolled in to form tubes, the agents being larvae 

 of Sawflies of the genus Nematus, or else Gall-midges, 

 belonging to the Cecidomyidce. (3) Certain Mites also, 

 of the genus Phytoptus, roll the margins of the leaves 

 of some kinds of plants, so as to form narrow tubes, in 

 which they live for protection. Few cultivated plants 

 have the leaves rolled by these Mites; though Hawthorn 

 and Sloe occasionally have their leaves a good deal 

 injured in this way. 



LEAFSTALK. The (unexpanded) base of a leaf, 

 connecting it with the stem. 



LEAFY. Covered more or less with leaves ; of the 

 consistency of a leaf. 



LEATHER JACKET. A common name for the 

 grub of the Crane Fly (which see). 



LEATHER- WOOD. See Dirca palustris. 



LEAVENWORTHIA (named in honour of M. C. 

 Leavenworth, an American botanist, who died in 1862). 

 ORD. QruciferoR. L. Michauxii thrives in any ordinary 

 garden soil, and succeeds best when treated as a half- 

 hardy annual. Propagated by seeds, sown in the open 

 border, in spring. 



L. aurea (golden) is quoted by Dr. Asa Gray as a mere synonym ; 

 it is described, however, as having yellow flowers, so would be a 

 desirable variety, from a garden standpoint. 



L. Michauxii (Michaux's). fl. rosy-lilac, with a yellow eye, 

 freely produced on erect scapes. June. I. slender, lyrately- 

 pinnatifid, tufted, h. Sin. United States, 1868. (B. M. 5730.) 



LEBANON, CEDAR OF. See Cedrus Libani. 



LEBECKIA (said to be derived from the native 

 name of some of the species). ORD. Leguminosce. A 

 genus containing about twenty-four species of greenhouse 

 shrubs, all natives of Southern Africa. Flowers yellow, in 

 terminal, often unilateral racemes ; bracts and bracteoles 

 small and inconspicuous. Leaves linear-filiform, one to 

 three-foliolate. Branches unarmed, slender, or much- 

 branched and spinescent, glabrous or silky. Perhaps the 



, . , 



L. cytisoides (Cytisus-like). fl. bright yellow, 

 longish pedicels. May. 1. long-stalke.t, tr 

 linear-oblong, silky, canescent. h. 2ft. to 4ft. 



Lebeckia continued. 



only species now in gardens is L. cytisoides. Some of 

 the plants formerly included here are now placed under 

 Aspalathus, &c. For cultivation, see Aspalathus. 



large, on spreading 

 trifoliolate ; leaflets 

 (B. M. 1699, under 

 name of Crotalaria pulchella). 



LEBRETONIA. Included under Pavonia (which see). 



LECANIUM. Included under Trichomanes (which 

 see). 



LECANOPTERIS. Included under Polypodium 

 (which see). 



LECHENATTLTIA. See Leschenaultia. 



LECYTHIDEJE. A tribe of Myrtacece. 



LECYTHIS (from lecythos, an oil-jar; in allusion to 

 the shape of the seed-vessels). ORD. Myrtacece. A large 

 genus (sixty-four species have been described, but not 

 so many are entitled to specific rank) of stove trees, some- 

 times very large. They are confined to tropical mostly 

 Eastern America. Flowers often rather large, disposed 

 in simple or paniculate, axillary, terminal racemes ; calyx 

 segments and petals six, rarely four, the former imbri- 

 cated. Fruit coriaceous or woody, globular or cupuli- 

 form, furnished at top with a lid, which falls off when 

 the fruit is ripe. Leaves alternate, coriaceous, .entire 

 or serrate, dotted. Few of the species are -known to 

 cultivation. They thrive in a mixture of loam and sand, 

 and require a strong heat. Propagation may be effected 

 by cuttings of the ripened wood, inserted in sand, under 

 a glass. Under the name of Sapucai Nuts, the seeds 

 of L. Zabucajo are sold in our shops as a substitute for 

 Brazil nuts, to which they are far superior. 

 L. grandiflora (large-flowered), fl. 2in. in diameter ; petals deep 



red, very hard ; pedicels thick, shorter than the largest petal. 



April, fr. ovate, nearly globose, 4in. to Sin. in diameter ; seeds 



edible and very palatable. I. petiolate, oval, acute, quite entire, 



stiff, h. 60ft. to 80ft. Cayenne, 1824. 



LEDEBOURIA. Included under Scilla (which see). 

 LEDENBERGIA (a commemorative name). ORD. 

 PhytolaccacecB. A monotypic genus, the species being a 

 very ornamental-leaved stove climbing shrub. It thrives in 

 a compost of rich loam and leaf mould, and requires 

 ample drainage and plenty of pot room. Propagated by 

 cuttings, placed in sandy loam, under a hand glass, in 

 gentle bottom heat. 



L. roseo-aenca (rosy-bronze), fl. whitish, small, inconspicuous, 

 disposed in long, drooping, axillary racemes. I. large, alternate, 

 thick, obovate-lanceolate, dark shining coppery - green on the 

 upper surface, and bright rosy- violet colour beneath. Steins and 

 branches reddish-purple. Central America, 1869. (I. H. 591.) 

 LEDOCARPUM. A synonym of Balbisia (which 

 see). 



LEDUM (from Ledon, the ancient Greek name used 

 by Dioscorides for the Cistus). Labrador Tea. STN. 

 Dulia. ORD. Ericaceae. A small genus (four or five 

 species) of very ornamental, dwarf, hardy evergreen 

 shrubs, inhabiting the Frigid and Arctic regions of the 

 Northern hemisphere. Flowers white, disposed in many- 

 flowered terminal umbels; petals five, obovate, obtuse, 

 spreading; stamens five or ten, rarely six or seven, ex- 

 serted; pedicels bracteate at base. Leaves alternate, 

 shortly petiolate, linear or oblong; margins recurved, 

 entire, rusty underneath, coriaceous. Like most other 

 so-called American plants, the species succeed best in well- 

 drained beds of peat and leaf mould, to which sharp sand 

 or road grit should be added. Propagated by seeds, but 

 principally by layering, in sandy-peat soil, and by care- 

 ful divisions of established plants in autumn and winter. 

 Raising and establishing young plants takes some con- 

 siderable time to accomplish. When transplanting 

 Ledums, it is necessary to keep the ball of earth surround- 

 ing the roots as intact as possible. 



