336 THE ORCHID REVIEW. [NOVEMBER, 1909. 
ornatissimum has appeared among the recent importations from the Philip- 
pines. The difference in colour and in the shape of the leaf are very well 
shown in the figures cited, but whether both are forms of a single species 
remains uncertain. The identity of the original Bulbophyllum (Cirrho- 
petalum) Mannii, and the real habitat of C. ornatissimum also remain 
doubtful. It would be interesting if any reader can throw further light on 
the matter. RR Ms 
THE PRODUCTION OF HORTICULTURAL VARIETIES. 
Tuis was the title of the second ‘‘ Masters’’ Memorial Lecture, delivered by 
Professor Hugo de Vries at the R.H.S. meeting held on September 28th, 
and although it contained no reference to Orchids, a few notes’ on the 
general principles involved should be of interest. 
The Lecturer remarked that if the facts of variation supported the 
argument for evolution, which was now generally admitted, the process by 
which variations arose became, in all its details, a most interesting and 
important subject of enquiry, for the laws governing the process are the 
same in both cases, though the details may and probably do differ. In 
‘* fixing’’ varieties which arise in gardens, where numerous closely allied 
forms grow in proximity, one has to contend against the difficulty of. cross- 
pollination, and especially so where the variations which it is desired to 
develop are only faintly indicated at first, as in the doubling of flowers or 
variegation of foliage. Only after careful selection do such variations 
become marked enough to make them worth cultivating as novelties. 
There are two distinct types of variation with which the horticulturist 
has to deal, the ‘‘constant’”’ and the ‘‘ever-sporting” variety, and the 
former Professor de Vries calls ‘‘ mutants,” because they arise suddenly and 
breed true to type when self-pollinated. Examples of mutants were 
furnished by white ‘‘ sports”’ of many flowers, and by ‘‘ dwarfed’ varieties, 
in which cases the florist’s work consisted solely in securing isolation. The 
occurrence. and extent of variegation depends largely upon the method of 
cultivation, and the extent of doubling may vary enormously, even on the 
same plant and at different seasons of the year. Small indications of 
possibilities appear first, and the florist has to isolate them and work them 
up by constant selection. 
The lecturer showed how variations had been produced under his own 
observation in plants whose history was known for many generations, and 
various examples were thrown upon the screen, among them being numerous 
examples of the genus Cinothera. He also showed many views of his 
experimental garden in Amsterdam, including the gauze cages under which 
the plants were cultivated so as to ensure the exclusion of insects likely to 
carry the pollen about. Thelecture was followed by a short discussion. 
