AUTUMNAL CLIMATOLOGY 
BOTANICAL GAZETTE [OCTOBER 
xomvaoavaa | over-favorable conditions, in the same degree 
asst | + | the autumnals claim possession of that less 
rama | t | suitable period during the closing days of 
Nam YEN | ‘3 | vegetative activity, and for similar reasons. 
presomp | BS Each group has been able on account of 
Cot es peculiar characteristics to work into and 
3 | Pepe | dS occupy these periods unsuited for plants of 
B ate, eo less xerophytic tendencies, as their periods 
SOM ge of growth and reproduction fitted into these 
bea ig seasons of the year, extremes in each case, 
as where the great majority of forms could 
aes e not succeed. As floral activity is more 
is —| definitely restricted than vegetative, which is 
8 ee largely accomplished in earlier periods, . 1S 
also evident that the problems of pollination 
ae ‘ and seed dissemination must have been no 
— | small factor in working out through selec- 
in a tion the floral restriction of these forms. 
a The following species extend over from 
'¢ | the serotinal aspect, but are rendered incon- 
a ern 8 spicuous by the overtopping layer of a few 
autumnal species: Verbena stricta, Carduus 
“a |= | undulatus, Ratibida columnaris, Meriolix 
es serrulata, Polygala alba, and Lygodesmia 
‘tno | ™~ | juncea. They become less and less conspl 
wes Cuous as the period advances. 
3 Ween As ruderals we may note Melilotus alba, 
f= | coming over from earlier aspects, Laciuca 
Sapte | canadensis, and Salsola tragus. ne a 
: * Conditions here are but the couetes 
"| and accentuation, during the early part 
; weap : = aspect at least, of those of oe siege 
: Sere: G less pronounced toward early September; and 
| | + | toward the middle of the month ~ 
wane ‘S| gradually into those more settled — 
"| | tions of early fall in which maturation ® 
