114 Trans. Acad. Sci. of St. Louis. 



Funiculus and Adjacent Parts. 



Under this head I shall discuss the hilum, the hilar groove, 

 micropyle, funiculus, arillus, and arilloid processes (Zwillings- 

 hocker, tuberculi gemini). 



Elsewhere the statement was made that the Malpighian 

 cells curve toward the funiculus and that a double row is 

 formed. According to some writers one row belongs to the 

 testa, the other to the funiculus. I have considered both rows 

 as a part of the testa. In each row alight line occurs. The 

 outer row shortens toward the edges where it meets the 

 funiculus ; the inner shortens toward the tracheid island. 



A section cut across the hilar groove shows a character- 

 istic bundle of tracheids, the so-called " tracheid island " of 

 Tschirch andOesterle (267). It is oval in outline, connecting 

 at the upper end with the hilar groove (Nabelspalte of the 

 Germans). The tracheids vary in length, being short in the 

 upper and lower parts and much longer in the center. The 

 island is surrounded by several rows of thin-walled cells. 

 The parenchyma in the hilar region has greatly increased and 

 frequently consists of three differentiated parts, rather loosely 

 arranged: (1), thin-walled parenchyma cells, a continuation 

 of the nutrient laj^er; (2), thicker-walled, star-shaped paren- 

 chyma with numerous large intercellular spaces from which 

 the air is not easily expelled; (3), thin-walled, elongated 

 parenchyma surrounding the tracheid island ; these cells elon- 

 gate tangentially at the lower end. In Mucuna pruriens 

 twenty rows of these cells occur below the island. 



A cross section through the funiculus of Mucuna pruriens 

 shows a well-developed fibro-vascular bundle in the center, 

 which consists of phloem and xylem. The elements of the 

 bundle differ in amount in various parts of the funiculus, and 

 in different seeds. This is true of the species studied by 

 Dahmen (43), — Pisum sativum, Vicia Faba, Orobus niger, 

 and Lupinus luteus. The phloem consists of the usual sieve 

 cells and their accompanying elements. The xylem in all 

 species thus far studied consists of spirally thickened tra- 

 cheids. The bundle is surrounded by a parenchyma sheath. 

 The epidermal cells above the rim have their outer walls 



