88 BOTANY OF CROP PLANTS 



by examination of this unknown plant, we find now that there are "three 

 spikelets at each joint of the rachis," it must belong to the genus Hordeum 

 (barley). 



The "key" shows many of the characteristics of a group. Consider 

 Triticum (wheat), for example. One can see by the key that "spikelets fall 

 from the inflorescence without the glumes, which remain attached to the 

 rachilla; spikelets one-many- flowered; rachilla often produced beyond the 

 upper glume; grain with a longitudinal furrow; tuft of hairs at tip of ovary." 

 Furthermore, that the "inflorescence is a spike"; that there is "one spikelet 

 at each joint of the rachis," and the "glumes are not bristle-like, but broad," 



Spikelets falling from the inflorescence entire (glumes attached to grain), one- 

 flowered, or if two-flowered the lower one staminate; rachilla not pro- 

 duced beyond the flowers; grain without a longitudinal furrow; no tuft 

 of hairs at tip of ovary. 

 Flowers staminate and pistillate; borne in separate inflorescences on the 



same plant, i.e., monoecious (Fig. 57), Zea (maize or Indian corn). 

 Flowers perfect or staminate; when the staminate are present, borne in 

 same inflorescence with perfect. 

 Spikelets much compressed laterally (Fig. 75), Oryza (rice). 

 Spikelets cylindrical or somewhat compressed dorsally. 

 Lemma and palet thin and papery, much more delicate in texture than 

 the empty glumes (Fig. 71), Andropogon (sorghum, milo, broom 

 corn, etc.) 

 Lemma and palet, at least of perfect flower, never thin and papery, 

 parchment-like or leathery, hard and shiny, very different in color 

 and appearance from the glumes (Fig. 83), Chatochloa, Echinochloa, 

 Panicum, Pennisetum (millets). 

 Spikelets falling from the inflorescence without the glumes, which remain 

 attached to the rachilla; spikelets one to many-flowered; rachilla often 

 produced beyond the upper glume (Fig. 47) ; grain with a longitudinal 

 furrow (Fig. 34); tuft of hairs at tip of ovary (Fig. 34). 

 Inflorescence a panicle (Fig. 45), Avena (oats). 

 Inflorescence a spike. 

 One spikelet at each joint of rachis. 



Glumes bristle-like (Fig. 55), Secale (rye). 

 Glumes not bristle-like, broad (Fig. 28), Triticum (wheat). 

 Three spikelets at each joint of rachis (Fig 49), Hordeum (barley). 



■ Key to Small-grain Seedlings^ 



iThis key is taken verbatim from Carrier. The "collar" is a narrow 

 band, usually of different color from the sheath and blade, at the junction of 

 leaf and blade. The "claw-like appendages" are the auricles. 



