RELATIONSHIPS OF THE INDEFINITE INFLORESCENCES. 161 
physiological adaptation to circumstances. The factors first men- 
tioned are but the expression of these two fundamental causes. 
this point clear, it will be necessary to 
begins t v i 
leaves are formed one after the other; the lower ace being the 
older, are naturally the first to attain full development. As summer 
advances there comes a time — circumstances _ favourable, 
the well-known terminal raceme begins to be developed. If we 
examine the tip of the rik ‘ae the formation abe saver ral floral 
shoots, the chief point of interest which will be air ih is the 
relative length of the internodes. Near the growin will 
seen a number of very crowded nodes, some of which—‘‘ the highest” 
—bear modified leaves or bracts, in the axils of which the floral 
shoots are developing. Below these are similar nodes bearing the 
last-formed unmodified leaves. At the extreme apex the internodes 
are so short as to pe ——,. non-existent to the naked eye, but 
as we descend the s _— become longer and longer. The older 
the leaf the ae te inte Sieils. In this way the flowers and 
leaves are developed and matured in acropetal succes 
uch an inflorescence owes its form to the development o 
elongation of the internodes of not only the primary, but also the 
secondary floral axes, It is obvious thas t to fulfil both of these 
supply of vital energy over and above that required to carry on the 
various other functions of plant life. Further, the energy* required 
to produce a complicated inflorescence such as the panicle or the 
compound umbel must be greatly in excess of that required for the 
th 
herbs, such as Dipsacus sylvestris L., Epilobium angustifolium L., or 
Arundo Phragmites L., is able to command a far greater supply of 
vital energy than small A assay such as Draba aizoides L. or Silene 
acaulis L., ace e height does not exceed a few inches. 
magine the probable course of events in the case of 
species hone supplies of energy available for flower production are 
strictly limited. Alpines are of great interest as affording instances 
of such plants. Many such are only free from snow for a few weeks 
i 
reserves against the approaching winter. The chief object of such 
a plant is to reproduce itself: to flower and if — — its 
before it is again buried beneath the snow. It is easy to 
« sare word “energy” is used in this paper in the sense of “ the vi 
energy of a plant of which growth is the expression or result. ” Vide Bailey, 
poo hg of the Unlike, p. 25, &c. 
Journat or Borany.—Vou. 37. [Aprin, 1899.) M 
