310 smith: upplication of the theory of 



The methods <»t' measurement were simple. They varied 

 u ith fche plant measured and will be given with the description 

 <<\ ilir results in each rase. 



II.— OBSERVATIONS. 



I. FLOWERING SHOOT OF AGAVE AND FUEGE(EA. 



\- is well known, these plants grow for a, number of years 

 without flowering, storing up in the I hick leaves a large reserve 

 of food, 



At Mir cud <>t' this period of vegetative activity a. flowering 

 -hoot is produced, which grows out to form a large terminal 

 inflorescence. The production of the inflorescence exhausts the 

 supply of reserve material, and when the flowers (and afterwards 

 the fruits) have appeared and matured, the whole plant dies. 



Several opportunities presented themselves of measuring 

 the rate of growth of the flowering shoot of species of Agave. 

 ■ oid Purcroea and the results of the more instructive rases arc 

 given in Plate I. 



In these cases the measurements were made in the following 

 waj \ bamboo pole was placed firmly in the ground as 

 mar as possible to the growing shoot. A scaffolding having 

 been erected so that the top ofthe shoot could be easily readied 



-metre scale was placed so as to rest on the tip of 

 the growing shoot. The scale was placed horizontal by 

 me. nc of a spirit-level resting on it, and the height thus 



rked oil on the pole by means of a penknife or a sharp- 

 pointed lead pencil. 



The tips of the large sheathing bracts which terminate the 



dioot were Scarcely Or not at all injured Ity this process, and 



luocessive measurements of the same height never varied by 



more than "06 cms. Iii the case of the plant measured at 

 K.nidy . which was diffioult of access. Ih is error may have been 



edi d Measurements were made at intervals of t wo hours 

 and the shade reading of the drj and wet bulb thermometers 

 u i aken at the same < ime. 



