8 THE UNIVERSITY SCIENCE BULLETIN. 



four miles southeast of Pratt, Kan. When gathered it was placed 

 in a two per cent formalin solution. The specimen is ordinary in 

 size, and is fresher than those commonly found in the early fall, 

 due, no doubt, to the unusually frequent summer rains. 



METHOD OF PROCEDURE. 



The methods of anatomical study employed by Stevens ('11) 

 were followed. Microchemical tests were made on sections cut 

 free-hand with the razor. Microtome sections of all sizes of stem 

 and root were made, and sections were made of five regions of 

 stem and root imbedded in both paraffin and celloidin. Region I 

 (fig. 29, m") of the stem was cut within 5 mm. of a young branchlet 

 tip; region II (fig. 29, o") within 1 to 3 cm. of a young branchlet 

 tip; region III (fig. 29, h") from a branchlet of medium size; 

 region IV (fig. 29, r") from the base of a main branch; and region 

 V (fig. 29, s") from the main axis, 7 cm. above the root, where the 

 diameter is approximately 1.5 cm. The sections of the five re- 

 gions of root correspond in size to the five regions of stem. The 

 general drawings mapping out tissue regions were made from 

 material not imbedded, but the detail drawings were made for the 

 most part from material imbedded in paraffin, but in a few in- 

 stances in celloidin. All drawings were made with the use of the 

 projectoscope. 



THE STEM. 



The main axis of the stem in my specimen is 15 cm. long; it 

 varies in diameter from 2 cm. close to the root to 1 cm. where the 

 last branches go off. From this main axis arise uniformly twelve 

 erect branches, which are not straight but irregularly zigzag, and 

 which are diffusely branched to fill out the globose contour of the 

 plant. The bases of the two uppermost main branches unite to 

 form the tip of the main axis of the stem. The branching habit 

 of a main branchlet is shown in fig. 1. The stem has a glabrate 

 surface, and a light green color with a purple tinge; but parts of 

 the main axis and the large branches are colored a light brown. 

 Due to a well-developed vascular system and collenchyma tissue 

 of the ribs, even the branchlets are very resistant to breaking. 



The zones of tissue for the five regions of stem are mapped out 

 in figs. 2, 3, 4, 5 and 6; the detail of the tissue for the first four 

 upper regions of stem is found in figs. 7, 8, 9, 10, and 11. The tis- 

 sues of the five regions of stem, from the epidermis to the pith, 

 inclusive, are described in the following paragraphs. Discussions 



