291 the described species afresh, and althoufrh in the main my conclu- 

 sions remain the same with regard to synonymy, I have mede some 

 important modifications in conseouence of the greater amount of li- 

 ving material I have been able to examine, and more especially on 

 account of some very important information I have received from 

 Dr. J. Mulr concerning these plants. 



Dr. ^'-uir has made the very interesting discovery that under 

 natural conditions some (nerhans most) of the species exist in tv/o 

 different forms that are connected v/ith each other by a series of 

 intermediate forsm, so thet although the two ends of the series are 

 very different in general appearance they cennot be disti.lguished 

 as distinct varieties, ^r. ^uir states J "-^t one end of the series 

 is a harder, smaller and d-^rk^r green plant, often v/ith some tinge 

 of broA'm or red, with less juice; at the other a lighter green, 

 softer and much larger form, '^hey may both equally well beer flow- 

 ers, and the smaller form seems a complete example therefore. In 

 the same locality both mey be found, the smaller, harder type in 

 more exposed and on shallov/er soil, for example, on a flat rock or 

 where there is less moisture, '^e softer, juicer form further away, 

 under the shelter of a shrub, in deeper soil or where moisture is 

 retained longer. Sometimes the harder, smaller form seem merely 

 younger. In cultivation (in So^+h •'^■f rice ) the harder form gradually, 

 even after a year or two years, seems to change into the other form. 

 But the harder fonn is more resistant to climatic changes; for 

 example, frost congeals the juices of the softer fonn, which dies, 

 v^ilst the harder form survives (see also a note under G, lf=tum). 

 The bevelling and hooks at the ends of the leaves of some species 

 exist in miniature in the harder form and are therefore often not 

 so noticeable as in the more juicy forms. J% specimens of G. 

 Muirfi, of vjhich I had both extreem.e forms, and of v/hich the smaller 

 and harder form had remained as such since 1924, has now (June 1926) 

 during the past fev; weeks undergone a change and become greener and 

 juicer and are quickly assuming the other form. 



An illustration of these two extreme forms is given in "^'ig. 122, 

 reproduced from, ^he "hardeners' Chronicle, 1921, Vol. UOL p. 327, 

 vrhere I thought the plant might be G. pustulatum, which I had not 

 then seen, but noe that ^ know that species, I fjnd it is distinct 

 end I have named the plant figured G. erectum. -*■ there called at- 

 tention to th^ remarkable differnce between the plants represented 

 growing together in lii e same pot and raised from seeds taken from 

 the same seed-r,od, but did not then understand the significance of 

 it. Dr. loir's discovery throws light upon it, but does not com- 

 pletely explain the reason for it. x\t the present time both the 

 plans represented in J'ig. 132 are indistinguishable from one another. 

 Did one of the plants obtain most of the v.'ater supplied to that 

 pot at the expense of the other plant and so partly starve the lat- 

 ter, or is ther some other explanation? At any rate, i^r. ^Riir's 

 discovery clearly supports the view it vail be found I have taken 

 under G. latum, that all the figures of Salm %ck's that I have 

 quoted under the species that its variety cultratum represent only 

 individual forms of one and the same species, especially as it is 

 confirmed by the fact that in my own green house one plant of 

 G. latum is actually transforming itself into the variety cultratum, 

 but v.-hether it v;ill perpetually retain the curvature of its leaves, 

 by which alone that variety is distinguished from typical G. latum, 

 remains to be seen. 



Dr. i!uir believes (and in this I quite agree with him) that 

 the early botanists, v^o did not know of this variation, were misled 



