258 DR J. M. MACFARLANE ON THE 



how to gauge results accurately, need not deter us from attempting in the future to 

 grapple with it. My attention was drawn to it by observing the resisting power of 

 Montbretias during the past winter (1890-91). In the note above referred to in the 

 Gardeners' Chronicle I shortly drew attention to it, and the sequel will best be understood 

 by quotation of the passage : — 



" The behaviour of Montbretia Pottsii, Tritonia aurea, and M. crocosmcejiora in the 

 Edinburgh Garden during the past winter seems suggestive. The corms of the first 

 appear scarcely to have been injured. Those of the hybrid have been largely killed off, 

 at least to the extent of 60 per cent., while Tritonia — never hardy in exposed ground — 

 has survived only where it is planted against, and can creep along, the outer side of a hot- 

 house wall." 



Confirmatory evidence api3eared, curiously enough, in the same Number. A corre- 

 spondent, after a visit to Van Houtte's nurseries at Gend-Brugge, wrote: — "The 

 Montbretias, about 6 inches below ground, were mostly frozen ; the most hardy variety, 

 Pottsii, was unharmed." Another correspondent wrote : — " Montbretia Pottsii has sur- 

 vived, though M. crocosmcejiora has almost if not altogether died out." 



Philesia buxifolia is a hardy plant, and resists well our winter colds. Lapageria 

 rosea requires the temperature of a cool hothouse to flourish, while the hybrid succeeds 

 if kept protected from frost and the more cutting winds. In the southern counties of 

 Britain it lives and flowers out of doors. 



An extremely important line of investigation, alike on theoretical and practical 

 grounds, is suggested by these relations to climatic surroundings, and a solution of the 

 problems involved can only be successfully attained by utilisation of our botanic gardens, 

 and the establishment in these, or in some special institute, of experimental biological 

 departments. 



As somewhat akin to the above may be mentioned the growth-forms and growth- 

 periods of Carduus Carolorum and its parents. C. palustris is a biennial which forms 

 during the first season a short root and stem system with a close-set rosette of leaves. 

 In the succeeding season the stem elongates greatly, develops a branched mass of capitula, 

 and when these have shed their fruits the whole plant dies away. In C. heterophyllus an 

 extensive system of creeping perennating rhizomes is formed which annually send up leaf- 

 and flower-stalks. From the axil of a hypogeal scale a bud grows out, or several may arise 

 in a season, which run horizontally underground, often to a length of twelve to thirty inches, 

 from the flowering shoot. These, as well as the old rhizome portion, persist after the 

 aerial stem has died away. In C. Carolorum there is a curious combination of both growth 

 forms, with the practical outcome that the plant is perennial like the latter parent, though 

 in a weaker and less perfect manner. At the base of many flowering shoots a bud or buds 

 arise in the axil of a hypogeal leaf, and these grow outwards and upwards, sometimes 

 attaining a length of from three to ten inches. The parent part in most cases dies away, 

 but the lateral shoots continue the growth. A very similar state of things is encountered 

 in Montbretia crocosmcejiora and its parents. 



