8 



GRASSES OF IOWA. 



The organs or parts of grasses, as in other plants, are those 

 of vegetation and those of reproduction; to the first belong the 

 root, stem or culm, and leaves; to the second the stamens and 

 pistils. 



Roots. 



CrToss characters. — Grass roots are always fibrous. The more 

 or less strong underground rhizomes are often called roots; 

 they are not true roots, but are specially modified stems. 



Minute anatomy. — The purpose or func- 

 III tion of the roots is to obtain nutrient mater- 



ial from the soil and conduct these matters 

 through certain channels. It is important, 

 therefore, to consider the structure of the 

 roots from an anatomical standpoint. One 



Fig. 1. Brace roots of 

 Mexican corn grown on 

 college farm. (King.) 



Fig. 2. Blue grass and Its system of 

 roots. (King.) 



illustration will serve to show the struc- 

 ture, and for that purpose the corn plant 

 may be taken as a type.* 



The first root is early formed by the plant; 

 it exists in the seed. When appropriate 

 material, moisture, warmth and oxygen is 



*For literature see: J. W. Harshberger. Maize; A Botan- 

 ical and Economic Study. Oontr. Bot. Lab. Unl. Penn. 1: 

 75-302. 1893. Strasburger, Noil, Schencli and Schlmper 

 Lehrbucli der Botanili. .'i.'xS, 1894. J. Hach's Lecture on the 

 Physiology of Plants; English translation by H.Marshall 

 Ward. A Text-book of Botany. 858: M>\ f. G. Haberlandt. 

 Physiologlsche Pllanzenanatomio.550: :',« /. De Bary, Com- 

 parative Anatomy of the Vegetative Organs of the Phane- 

 rogams and Ferns; English translation by F. O. Bower 

 and D. H. Scott. 659: 241 f. 



