AN ENCYCLOPEDIA OF HORTICULTURE. 



101 



Guatteria continued. 



ornamental stove evergreen trees or shrubs, all natives 

 of the warmer parts of the New World. Flowers yellowish- 

 white, greenish, or dusky ; peduncles one-flowered, axillary 

 or lateral, solitary or fasciculated. Leaves feather-nerved, 

 alternate, entire, exstipulate. Guatterias thrive in a com- 

 post of loam, peat, and sand. Propagation is readily 

 effected by cuttings, inserted in sand, under a glass, in heat. 

 Probably G. Ouregou is the only species in cultivation. 

 G. Ouregou (Ouregou). 



ped 

 lar, 



uncles axillary, short, two to 



four ; calyx segments triangular, pointed ; petals rusty-velvety, 

 obovate, interior longer ; carpids ovoid. I. obovate-oblong, 

 cuspidate, cuneate at the base, shining above, glabrescent be- 

 neath ; veins prominent. Caribbean Islands. A tall tree. SYN. 

 Anona chrysopetala. 



GUAVA. See Fsidium pyrifenun. 

 GUAZUMA (name of Mexican origin, employed by 

 Plumier). Bastard Cedar. SYNS. Bubroma and Diuro- 

 glossum. ORD. Sterculiacece. A genus containing about 

 five species of ornamental stove evergreen trees, natives 

 of the tropical regions of both hemispheres. Flowers 

 small; cymes axillary, shortly pedunculate. Leaves un- 

 equally dentate, often oblique. The species thrive in a 

 compost of peat and loam. Cuttings of ripened shoots 

 root freely in sand, under a glass, in heat. 

 G. ulmifolia (Elm-leaved), fl., petals yellow, with two purple 

 awns at the apex. August. A. 40ft. to 60ft. A wide-spreading 

 tree, not unlike the Elm, with leaves that sleep hanging quite down, 

 whilst the petioles remain entirely stiff and straight. West 

 Indies, 1739. SYN. Bubroma Guazuma. 



GUELDER ROSE. See Viburnum Opulus. 

 GUERNSEY LILY. See Neriue samiensis. 



GUETTARDA (named in honour of John Etienne 

 Guettard, 1 71 5-1 78G, member of the Academy of Sciences 

 at Paris, who published, in 1747, a catalogue of the 

 plants growing in the vicinity of Estampes). Including 

 Cadamba and Laugeria. ORD. Rubiacece. A genus 

 containing about fifty species of ornamental stove ever- 

 green shrubs or small trees, natives chiefly of tropical 

 America. Flowers sessile and unilateral along the branches 

 of the peduncles, and solitary in the forks ; corolla salver- 

 shaped, with a cylindrical tube, and from four to nine 

 oval-oblong lobes ; peduncles axillary, bifid. Leaves 

 ovate or lanceolate. Guettardas succeed best in peat and 

 loam mixed. Propagated by cuttings, inserted in sand, in 

 heat. 



G. odorata (sweet-scented).* fl. reddish, nearly lin. long, villous 

 on the outside, very sweet-scented at night; cymes bifid. Sum- 

 mer. I. oval, acute at both ends. A. 6ft. to 10ft. Tropical 

 America. 1818. Shrub. 



G. rugosa (wrinkled). A synonym of G. scabra. 



G. scabra (scabrous), fl. white ; peduncles compressed, villous, 

 almost four times longer than the petioles. I. obovate, mucronate, 

 coriaceous, scabrous above, reticulated and pubescent beneath ; 

 stipules lanceolate, acuminated, caducous. West Indies, 1818. 

 Tree. SYN. G. rugosa. 



G. speciosa (showy), fl. white, exquisitely fragrant, partaking 

 much of the scent of cloves, large ; cymes pedunculate, velvety, 

 much shorter than the leaves. June and July. I. broad, ovate or 

 obovate, downy beneath. Branches horizontal, forming a large 

 shady head. h. 30ft. Tropical Asia, 1771. Tree. (B. B. 1393.) 



GUEVINA (the native name). SYN. Quadria. ORD. 

 Proteacece. A monotypic genus. The species is a 

 greenhouse evergreen tree, succeeding in a peat and 

 loam soil. Propagated by cuttings, inserted in sand, 

 under a glass. 



G. Avellana (nut). /. white, hermaphrodite, geminate, pedi- 

 cellate, disposed in rather long axillary racemes ; perianth tube 

 cylindrical ; limb ovoid, recurved. June. fr. coral-red when 

 ripe, about the size of a cherry. Seed edible, largely used by the 



Chilians. I. alternate, impari-pinnate ; leaflets dentate. A. 40ft. 

 hili, 1826. This tree is hardy in the 

 South-west of England. 



. . , 



(in its native country). Chili, 



GUICHENOTIA (named in honour of Antoine 

 Guichenot, a French gardener and traveller). Including 

 Sarotes. ORD. Sterculiacece. A genus containing about 

 half-a-dozen species of greenhouse shrubs, confined to 

 extra-tropical Australia. Flowers nodding, solitary, or 



Guichenotia continued. 



shortly racemose; calyx five-lobed; petals five, small and 



scale-like. Leaves narrow, entire, with revolute margins. 



Guichenotias succeed in a loamy-peat soil. > Propagated 



by cuttings. The two species here described are probably 



the only ones yet introduced. 



G. ledifolia (Ledum-leaved). fl. white ; racemes several-flowered ; 

 calyx scarcely membranous, tomentose, the three prominent ribs 

 on each sepal giving it a rigid, striate appearance. Spring. /. on 

 very short petioles, oblong-linear, obtuse, mostly lin. to IJin. 

 long ; margins much revolute, wrinkled, thick, and soft ; stipules 

 similar, but usually rather shorter and more sessile. 1868. SYN. 

 Lasiopetalum Baueri, of gardens. 



G. macrantha (large-flowered), fl. purple, large, pendulous, in 

 racemes of two or three. March. 1. resembling those of G. 

 ledifolia. 1847. (B. M. 4651.) 



GUILANDINA. Included under Ccesalpinia. 

 GUILIELMA (named in honour of Queen Frederica 

 Guilielma [Wilhelmine] Carolina of Bavaria). ORD. 

 Palmce. A genus (included, by Bentham and Hooker, 

 under Bactris) containing three species of elegant stove 

 palms, confined to the tropical regions of South 

 America. Flower - spike branched. Fruit ovate, about 

 the size of a peach, produced in large pendulous 

 bunches. Leaves pinnate, hairy; leaflets and footstalks 

 spiny. Trunk slender, marked with circular scars, and 

 armed with exceedingly sharp spines. For culture, see 

 Bactris. 



G. speciosa (showy).* I. 2ft. to 4ft. long, pinnate ; pinnae about 

 1ft. long, lin. wide, apex broader, bifid, deep green nerves on the 

 upper sides clothed with slender black bristles ; petioles broadly 

 sheathing at the base, thickly armed with slender long black 

 sharp spines. Stem tall, densely spiny, slender. Amazon. SYN. 

 Bactris Gasipate. 



G. utilis (useful), fl. monoecious. Seeds edible, having the 

 flavour of chestnuts. I., young ones broad and bifid, bristling 

 with short spines, which spring from the ribs or veins, the 

 ridges of the upper surface and the costa beneath being the 

 parts furnished with them ; mature ones forming a handsome 

 pinnate head ; petioles densely spiny. Trunk slender, spiny. 

 Costa Rica, 1873. (G. C. 1873, 1271.) 

 GUINEA PEACH. See Sarcocephalus. 

 GUM AMMONIAC. See Dorema Ammoniacum. 

 GUM CISTUS. See Cistus ladaniferus. 

 GUM ELEMI. The gum-resin of Amyris Flu- 

 mieri (which see), &c. 



GUMMING. See Gummosis. 



GUMMOSIS, or GUMMING. Recent observations 

 on this highly contagious disease have shown that it is 

 caused by a fungus, which has been named by Professor 

 Oudemans Corynevm Beijerinckii. The mycelium of this 

 fungus appears to develop a ferment which penetrates 

 the adjacent cells and transforms the cell -walls, the 

 starch granules, and other cell contents into gum, 

 whether these cells belong to the host plant or to the 

 fungus. The ferment of the Coryneum can penetrate 

 into living cells e.g., those of cambium and can 

 modify their protoplasm so that the cells that they 

 afterwards produce by division form a tissue with new 

 properties. This tissue is the pathological wood 

 parenchyma. Sooner or later, this tissue begins, in turn, 

 to secrete the ferment, and to change into gum. The 

 quantity of ferment so formed is greater than the 

 amount originally present in the diseased cells. Gum- 

 ming can be propagated from diseased to healthy 

 places without mycelium extending from one to the 

 other. The action resembles the propagation that albi- 

 notic parts exercise on healthy ones. It is conjectured 

 that the channel of propagation is the phloem, and 

 that the contagion is the ferment. In other cases, the 

 mycelium of the Coryneum is the exciting cause of 

 Gumming. A similar disease produces gum arabic, gum 

 tragacanth, and, probably, many resins and gum resins, 

 "One point concerning the spread of this disease seems 

 c l ear the fungus itself cannot penetrate the bark : there 

 must be some abrasion or laceration of the latter before 

 thn gorm tubes can enter. These injuries may clearly 



