STUDIES OF SEED-PLANTS 149 



soaked seeds, and especially some which have begun to germinate, 

 it will be found that most of the two halves taken to be the coty- 

 ledons like those of the bean are masses of stored food (really nu- 

 merous cells stored with food) and that between them, in the center of 

 the seed, are two delicate white cotyledons joined to the hypocotyl, 

 which is at the hilum end of the seed. Carefully separate the coty- 

 ledons from the food-masses (called endosperm), taking care not 

 to break off the hypocotyl. The embryo will thus be freed from 

 all other parts of the seed. Examine the parts of the embryo, 

 especially in seeds which have begun to sprout. Notice the 

 epicotyl. 



Examine a series of seedlings from castor-oil seeds planted in 

 soil ; some placed in a tumbler as in 81 ; and some kept on moist 

 paper. Find out how the embryo gets out of the seed-coat ; how 

 it comes out of the ground ; what becomes of the endosperm ; why 

 the hypocotyl remains bent so long ; development of the cotyledons ; 

 compare the seedlings with those of bean and squash previously 

 studied. Make a series of sketches showing stages in germination 

 of castor-oil seed. 



139. Corn Grain. (L) NOTE : By corn is here meant Indian 

 corn or maize. In the United States the word is always so under- 

 stood ; but in other countries the word is used in its original sense, 

 meaning grains of any cereals corn, wheat, oats, barley, rye. It 

 is called Indian corn because found under cultivation by the Indians 

 when America was discovered by Columbus. The name maize is 

 from the Indian name, and the scientific name is Zea Mays. 



Materials : dried grains or kernels of sweet, "field," and pop- 

 corn; dried ears of corn; "green" corn on the cob (fresh or in 

 formalin solution) ; some ears with husks ; very young ears showing 

 the attachment of the silk; grains of yellow "field" corn soaked in 

 water for several days ; sprouted grains in all stages of development 

 (may be preserved in formalin) . 



Examine specimens of ears of corn with and without the husks 

 removed. The central axis or cob is really the mature form of a sort 

 of flower-stalk on which there were as many flowers as there are 

 grains on the ear. Each individual flower which forms a grain has 

 only the pistil, the petals and sepals being absent and the stamens 

 in separate flowers in the tassels at top of the corn plant. Since each 

 pistil develops into a grain, this is therefore a fruit in the botanical 

 sense ( 212) ; and each flower produces one fruit containing one 

 embryo. In the bean each flower produces one fruit (the pod), but 

 this fruit happens to have several seeds, each with an embryo, that 



