GRASS FAMILY 
187 
minute, usually perfect, arranged in spikelets consisting of a shortened 
axis (rachilla) bearing bracts, the lowest pair of bracts (glumes) empty, 
each succeeding bract (lemma) including a single flower and a 2-nerved 
bract (palea), the flower, lemma and palea together termed the floret. 
Spikelets arranged in panicles, racemes or spikes. Perianth none or 
represented by minute scales or lodicules. Stamens usually 3. Pistil 1, 
superior. Ovary 1-celled, 1-ovuled; styles and plumose stigmas 2. Fruit 
a grain enclosed in the lemma and palea. 
See figs. 11 and 12. Figure 11 shows a diagram of a grass spikelet. 
Figure 12 illustrates Wild Oat, Avena fatua L.. showing a panicle of 
flowers (a)*, a spikelet (b) and a 
flower (h). The spikelet consists of a 
lower or first glume (c) and upper or 
second glume (d) with 3 florets, each 
one of the florets showing its lemma 
(as at e) bearing an awn (as at f). 
The rachilla of the spikelet ends in a 
sterile point (g). The figure at (h) 
shows a single floret with the lemma 
removed, exposing the flower backed 
by its palea (i). Two lodicules (j) 
appear at base of the flower, which 
bears 3 stamens (k) and one ovary 
(1) with two stigmas (m). 
The Grass Family, consisting of 
5000 species, is the fourth largest 
family of seed plants. It is widely 
distributed in all parts of the earth 
from tropical savannahs, temperate 
plains and desert steppes to the arctic 
zones, and reaches in mountains the 
limits of phaenogamic vegetation. 
While not so rich in species as either 
Orchidaceae, Compositae or Legum- 
inosae, the Grass Family far sur¬ 
passes these and all other families in 
point of number of individuals, as well as in economic importance. 
Probably the grain of wild wheat was the first grass to be gathered for 
food by some wandering tribe of Mesopotamia or Palestine in prehistoric 
times. Its gathering from wild plants or from plants the result of ac¬ 
cidental sowing, led to its regular cultivation, the most important dis¬ 
covery, after the discovery of fire, made by the earliest of our primitive 
ancestors. Wheat, in particular, furnishes a food which can be stored 
for long periods without deterioration and which contains all the ingredi¬ 
ents necessary to maintain life indefinitely. The finding of wheat was a 
most important step in the emergence of man from a savage state; its 
use opened the way to the development of a settled life, to husbandry and 
the arts of civilization. (Cf. “A Grain of Wheat,” Pop. Science, Mo. 
82:33-45.) 
