> a. a, ¥ ) , ae fo ia 
p ee) fe he 4 ' “4 can 
qs _ . t : y 
eas 8 
Os Lhe External Form of Plants. — 121 
these are replaced by small secondary sfzkelets, as in some 
grasses. The individual flowers may also be less or more 
crowded, according to the greater or less elongation of the 
rachis. A spike with a thick fleshy rachis, and enveloped 
in a large bract growing at its base, as in Arum or Calla, is 
e termed a sfadix, and 
the enveloping bract 
a spathe. A deciduous 
spike with weak ra- 
Am X\ chis [and unisexual 
| flowers] is a cathin 
or amentum (Fig. 
Be N 
y 
J en ~ « “s 
we f Pr SINS 
1 CAC > y 7, nam 3 
exh) a0 MN 
@ Y 4s GMS 
2 Za WR 
2 os 40 (ip ES ‘ ‘~~ f 
GH ; yy or 9 a BA \ Wy 
CTR TD UN AS a lll y 
O23 a ee a 
RY BS AH SS: 
Sik = 6, — 
“0 Cov Gh \ <—— 
in 3 
CxS wy Mw 
2 a 
Fic. 222. — Simple Fic. 223.—Catkin or Fic. 224. —Cone of 
spike of Verbena amentum of the oak. the Scotch fir. 
- officinalis. 
223) ; while a cone (Fig. 224)! or strobilus is a spike in which 
the rachis and bracts have become partially lignified [or 
the bracts are membranous]. ; . 
The raceme is distinguished from the spike by its separate 
* [The cone of Coniferze is here referred to as an inflorescence, as is 
also the case in some of the best English text-books ; according to the 
most recent investigations, however, it is not a collection of flowers, but. 
a fruit or ‘pseudocarp’ resulting from a single flower. In the hop we 
have an instance of a true strobilus with membranous bracts. —ED. ] 
