126 ^ot wepther the latter raethc^ f>nsv'ers very well and does no hr?rra, 

 rrovicled thpt it is not overdone, and at the same time sufficient 

 wa-ter is <?iven to soak down to the ref^ion of the root-tips, ?or, 

 if the letter are allowed to ffet too dry, so that they die, then 

 when water does reach them they rot and often cause the de^'th of* 

 the rilants. The watering of the more delicate species is nn art 

 that cnnnot he explained by vrords, and cpn only be acquired by 

 exr^erience. 



This p-enus, ps at present understood, is so vast and contains 

 so rapny species that are undescribed, althoufrh elready under culti- 

 vation, besides a lerp;e number that t am certain j'"et remain to be 

 discovered, th^t the monograrhs of the present day are quite use- 

 less "for distinpnjiishinf closely allied species, for many are so 

 sinilar in generpl p.'^r.earpnce that, when seen separately, two 

 srecies are liable to be (and often ?re) mistakenly supposed to be 

 identical. So that npmes under Avhich some of these rlants are 

 found in :?ardens pre often entirely wrong, -^s an instance I may 

 cite a '^Isnt cultivpted in g-^'Tdens and also described in Berger's 

 monorr8T>h of this a'enus ps bein;f^ ^'-. cprinons. It is not that plant, 

 however, but a smaller species allied to it, v?hich I last jerr 

 described in the Journal of the Linnean Society, Vol. XLV^ p. 36, 

 under the n^me of -1. p-ranulstum. Sometimes, also, synonyms are 

 menu'^actured by nurserymen, especiallj'" those on the Continent, who 

 seem only concerned in the selling of their plants, without taking 

 the trouble of identifying'^ them. As en instance of this, LI. 

 concinnum (5'ig. 49) may be quoted. This is one of the prettiest 

 and neatest of the steraless grou'^ that I have seen, and forms an 

 excellent contrast to its eouplly chprmine- ally, i-i. calcareum. 

 It has a rosette of short, blunt, somevhat clavate leaves, beauti- 

 fully marked with slir'htly raised, v^hite, wart-like spots. It 

 was described bv mvself in the "^srd. CJhron. for 1916, Vol. I^, p. 

 204, from a nl?nt formerly in the collection of i-'-r. ^. Siisha and 

 now in my possession, of which '^Ig, 49 is a life-size representa- 

 tion that, unfortunately, does not give a p-ood idea of the beauty 

 of the plf^nt, colour being absent. Aftenrards I learnt that it 

 had been figured by Winter in his ^eue und v/enig bekante i'flanzen 

 Deutsch Sud-'.-'est Af ricp , p. 38, f. 56 (l914), as being i»-. calcar- 

 eum, from which it is vevj distinct; and nov: it is being sold by 

 Continental nurserymen under the name of M. Schvvantesii. i^rom 

 some cause ouite unknown to me, I find that during some yeprs the 

 coloration of the leaves is much brighter and more pleasing than 

 in others. Possibly a difference of sunlight may produce this 

 effect. -'. calcareun also varies, but with me its leaves are 

 usually of a beautiful T>urplish tint. This confusion of names is 

 not to be v;ondered at in the present state of our knov^ledge, and 

 only when the undiscovered species of this genus have net rly been 

 exhausted, and a really vrarkable monograph of it made, can we 

 hone to remedy it. N. E. Brown 



(To be continued.) 



Mesembrvanthemum and some new (zenevs separated from it, 

 Gsrd. Chron. HI. 70 : 138. 1921. 

 (Continued from pape 125.) 

 138 



Whilst writing this, I have in flov/er two distinct species 

 from the Transvaal, so much alike in foliage that, if seen 

 senarately in different collections, v;hen out of flower, would 



