100 THE UNIVERSITY SCIENCE BULLETIN. 



the primary cortex in all regions of stem above region V, and on 

 certain sides of the stem in regions below, on sides where the 

 parenchyma has not been destroyed by the formation of cork 

 within, and no doubt so much anomalous phloem is necessary to 

 store and to transfer the food, made in the photosynthetic tissue 

 of the stem, for use in the rapid formation of the many anomalous 

 xylem-phloem zones. The photosynthetic products can be trans- 

 ferred readily from the parenchyma of the primary cortex through 

 the starch sheath and pericycle to the anomalous phloem. The 

 products of photosynthesis may also travel from one anomalous 

 zone to another because of the anastomosis of these phloem zones 

 (fig. 29, g'), and finally to the phloem of the primary vascular 

 strands, whence presumably it would go to the nutrition of the 

 seeds later in the season. 



The anomalous structure found in the Chenopodieae occurs in 

 all the Chenopodiaceae having considerable growth in thickness, 

 and is found in the Nyctagineae and the Amarantaceae, according 

 to Solereder ('08), in his review of the anatomical features of 

 Chenopodieae. He quotes from Morot the following statement 

 regarding the course of the development of the anomaly: "Sec- 

 ondary rings or arcs of meristem (the latter anastomosing re- 

 ticulately) arise in centrifugal succession in the pericycle (in- 

 ternally to the bast fibers, where these are present) and produce 

 secondary vascular bundles as well as conjunctive tissue of varying 

 structure. The xylem portions of these secondary vascular bun- 

 dles always arise on the inner, the bast portions on the outer side 

 of the secondary meristem. " 



According to Morot (fide Solereder, '08), the appearance of the 

 anomaly in transverse sections of the stem varies greatly between 

 two main types, relatively to the nature of the meristem, and of 

 the tissue intervening laterally between the bundles in each ring 

 of secondary bundles. In the first type the broad, woody rings 

 alternate in the radial direction with rings of tissue having thin 

 cell walls; the woody zones are traversed by medullary rays of 

 varying breadth, the cells of which have thin or lignified cell 

 walls. The rings of tissue with thin cell walls consist of phloem 

 portions of the vascular bundles associated with variable amounts 

 of a tissue, which Morot terms "parenchymatous conjunctive 

 tissue." In the second type, which occurs more commonly than 

 other types, the vascular bundles are arranged concentrically, 

 spirally, or irregularly, and the bundles are imbedded in tissue, 

 which Morot terms " prosenchymatous interfascicular tissue." 



