ROCHEA 



ROCK GARDENS 



1539 



place to induce perfect aud early maturity. During 

 winter the plants may be kept in a sunny frame or cool, 

 light greenhouse, with only sufficient water to prevent 

 shriveling. 



A. Clusters usually 2-flowered. 

 jasmlnea, DC. (CrrfssuZa Jas»itnea,Ker-Gawl). Stem 

 herbaceous, 4-12 in. high, decumbent, branched, flower- 

 ing part erect: Ivs. fleshy, oblong-oval, %-% in. long, 



2136. 



Rose Acacia— 



Robinia hispida 



(X y^.) 



1-2 lines wide: fls. white, tinted with crimson, sessile, 

 not fragrant, Wo. in. long. B.M. 2178. — Hybrids with B. 

 coccinea are figured in A.F. 5:433. 



AA. Clusters many-flowered. 



coccinea, DC. (Kalosdnthes coccinea. Haw. Crdssula 

 coccinea, Linn.). Plant robust, shrubby, 1-2 ft. high: 

 Ivs. very closely imbricated, 1-13>^ in. x %-l in.: fls. 

 bright scarlet, 13^-2 in. long, fragrant, borne in sum- 

 mer. Cape. Gn. 46, p. 360. B.M. 495. 



R. falcdta, DC. See Crassula falcata. p^ -^^ Barclay. 



ROCK-BRAKE. See Cryptogramma. 

 ROCK-CRESS. Arabis. 



ROCK GARDENS. Figs. 2137-40. Nature in time will 

 make a garden even on the unbroken surface of a rock, 

 by clothing it with lichens, algae and mosses of many 

 exquisite forms having much variety and often striking 

 brilliancy in coloring. If there are soil-filled cracks and 

 pockets then ferns and flowering plants will find a place. 

 At low elevations, however, these flowering rock-plants 

 are comparatively few, for soil accumulates rapidly and 

 strong-growing herbs, shrubs and trees, aided by favor- 

 able climatic conditions, soon cover the rock surface or 

 furnish so dense a shade that only mosses, lichens and 

 ferns will thrive. 



The ideal rock or alpine gardens are within that region 

 on mountain summits between the limits of tree growth 

 and the edge of perpetual snow, and in the correspond- 

 ing regions toward the poles, where the plants are pro- 

 tected from the rigors of a long winter by blankets of 

 snow and are quickened into a short period of rapid 

 growth by a comparatively low summer temperature. 

 Here, where there are deep, cool, moist rock crevices 

 and pockets filled with fragments of broken stone and 

 porous decayed vegetable matter, are the favorable con- 

 ditions wherein the real alpine plants can multiply their 

 neat and dainty cushions, tufts and rosettes of dense 

 and matted foliage and their abundance of exquisitely 

 formed and brilliantly colored flowers. A successfully 

 grown collection of these plants in contrast with ordi- 

 nary garden flowers would be like a collection of cut 

 gems as compared with one of rough minerals and 

 rocks, for they have an exquisiteness of finish and 

 depth of coloring that gives them as uniqxie a place in 

 the vegetable kingdom as they have in the plan of na- 

 ture. Surely there are men and women who, if they 

 knew these plants well, would be fired with an ambition 

 to excel in their cultivation ; and in so doing they may 

 enter a comparatively untrodden path if they will limit 

 their work chiefly to the alpines of this continent. They 



are represented in the New England mountain region 

 by such species as Arenaria Groenlandica, Loiseleuria 

 procumbens, Silene acaulis, Diapensia Lapponica, 

 Arctostaphylos alpina, Vaccinium cwspitosum, Saxi- 

 fraga rivularis, Veronica alpina, Geuni, radiatum, 

 var. Peclcii, Sibbaldia procumbens, Mhododendron 

 TjdpponicitiH, liryunthus taxifolia, Primula farinosa, 

 tidxifnKja njijxisiltfdlin, Aizoon and aizoides, Aster 

 polyphyllus and Woodsia glabella; and in the Rocky 

 Mountains and Pacific Coast Ranges by Erigeron uni- 

 florus, lanatus and ursinus, Actinella Brandegei and 

 andiflora, Artemisia borealis, scopulorum and al- 

 pina, Senecio Soldanella, Fremontii, pe- 

 trceus, uniflorus and wernerUefolius , Crepis 

 nana, Campanula uniflora. Primula Parryi 

 and suffruticosa, Androsace Chamajasme and 

 septentrionalis , Gentiana prostrata, frigida, 

 Newberryi, Parryi and simplex. Phlox bry- 

 oldes and ccpspitosa, Polemonium confertum, 

 Cassiope Mertensiana, Bryantlius JJreweri, 

 Draba streptocarpa, Parryi and nudicaulis, 

 Arabis Lyallii and platysperma, Smelowskia 

 calcycina. Lychnis niontana and Kingii, Ca- 

 landrinia pygmcea, Clnytonia megarrhizaf 

 Spraguea umbellata, Dryas octitpctala , Gcum 

 Kossii, Saxifraga chrysantha and liryoplxira ,. 

 Cysopteris alpina, Aplopappus pyg)naus, Lyallii and 

 acaulis, Omphalodes nana, Y&r. aretioides , Chionophila 

 Jamesii, etc. (Not all of these names are accounted for 

 in this work. They may be found in the Current Man- 

 uals of North American Plants.) 



The uncultivated American plants in this class are quite 

 as numerous and attractive as are the European species 

 that have been long cultivated there. Here alpines have 

 been but little cultivated. A very few easily grown 

 European kinds, like Aubrietia deltoidea, Achillea to- 

 mentosa, Camjianula Carpatica and Arabis albida, 

 are ofi'ered by American nurserymen and cultivated in 

 the open border. On a few private places small rock 

 gardens have been established, or advantage has been 

 taken of favorable local conditions to cultivate some 

 additional species, and in one or more botanic gardens 

 considerable collections have been at times maintained, 

 chiefly in frames. Generally what have passed for rock 

 gardens have been rockeries — mere piles of cobbles 

 raised from the surface of turf or piled against dry 

 banks in such a manner as rapidly to disperse instead 

 of slowly conserve all soil moisture. Even the most 







2137 A rockery bordering a lawn 



self-assertive weed fails to thrive in such a garden. A 

 little better than this was the rock garden at the 

 World's Fair, in which was the alpine plant exhibit 

 of the Royal Botanic Garden of Berlin, comprising 103 

 species, of which only 23 were alive in August. 



In general, we have a smaller rainfall, less humidity 

 and a larger proportion of sunny days than in England' , 

 to which we must look for the best instruction in tl '- 

 cultivation of alpine plants. This must be regarded iu 



