GRAMINE&. 249 



sepals, the third sepal having entirely aborted. Rudiments of 

 this third sepal are present in some of the gramineae. 



405. Other members of the grass family. — To the gramineae 

 belong also the wheat, barley, corn, the grasses, rice, etc. It 

 is one of the most important families from an economic stand- 

 point, furnishing a great variety of food for man and other 

 animals. The gramineae, while belonging to the class mono- 

 cotyledons, are less closely allied to the other families of the 

 class than these families are to each other. For this reason 

 they are regarded as a very natural group. 



Exercise 67. 



406. The wheat (Triticum sativum vulgare). — The wheat plant may be 

 studied as an alternate for the oat plant. 



The entire wheat plant. — Study the entire wheat plant, and compare with 

 the oat plant. Are the stems of the wheat single or are stools formed? 

 Since a germinating grain of wheat forms at first but a single stem, how are 

 the stools formed ? Examine young wheat plants to determine this. 



The inflorescence. — The " head " of wheat forms a single spike: Sketch a 

 spike. Remove a few of the spikelets, and note the jointed and zigzag char- 

 acter of the axis (rachis) of the spike ; note the attachment of the spikelets. 



The spikelets. — Note the empty glumes at the .base • ^determine how many 

 flowers there are in a spikelet. How many flowering glumes and palets are 

 there to each flower ? In a mature head of wheat determine how many of 

 the flowers in a spikelet ripen grain, and how, many are sterile? Are there 

 any of the spikelets which are completely sterile? Where are they located? 



Using a head of wheat at the time of flowering, .spread apart the members 

 of a flower with the aid of dissecting needles, and sketch the parts of the 

 flower, showing the glume, palet, -the three stamens, and the t pistil with the 

 plumose styles. Endeavor to find the lodicules. (See the description of the 

 oat flower for comparison.) 



Sketch an empty and a flowering glume to show the " nerves" and awns. 

 Compare the grain of wheat with a grain of corn. (See paragraph g.) 



Material. — Entire stools of young, fresh plants (may be obtained at any 

 time during autumn, winter, or spring) ; mature plants in flower (if they can- 

 not be obtained fresh they may be dried, preserving at the same time some of 

 the flowering heads in alcohol or formalin) ; ripe heads of wheat. 



