104 Tram. Acad. Sci. of St. Louis. 



mately colors like the other parts of the cell-wall. The wide 

 line colors darker and more rapidly than the cell-wall below. 

 Fickel states that it is not cellulose but that this portion of 

 the cell-wall is lignified. In 8icyos the light line is not 

 licrnin nor is it cellulose, but it appears to be a cuticularized 

 substance. 



Labiatae. The following writers have studied the testa 

 and pericarp. Mattirolo (401); Junowicz (128); Holfert 

 (116); Guignard (354, 67-77. /. 104-129) \ Chatin 

 ( 313, 86-96. :pl. 6. f. 4-9. pi. 7. /. 1-2. pi. 8. f. 1-5) ; 

 Harz (99, 2:866-869). Further references may be found 

 in my paper on Euphorbia (416). 



The Malpighian cells in this order occur in the wall of the 

 ovary. Junowicz studied Lallemantia, and Mattirolo the same 

 genus. Dracoce2)halum parvifiorum belongs to the same tribe 

 as Lallemaiitia. It has two light lines, one just underneath 

 the outer row of cells of the pericarp, and one in the lower 

 part of the Malpighian cells. Junowicz found two light lines 

 in Lallemantia. With chlor-iodide of zinc the light lines and 

 remainder of the cell-wall color dark brown. With phloro- 

 glucin and hydrochloric acid, the light line colors in the 

 characteristic way ; the remainder of the cell-wall soon colors 

 in the same way. The whole cell- wall is lignified. The cell- 

 cavity of the Malpighian cell terminates in a number of 

 branched canals. With sulphuric acid and iodine the cell- 

 walls color deep brown, they slowly dissolve in concentrated 

 sulphuric acid. 



Convolvulaceae. Several writers have investigated the 

 testa of this order. Lohde (396); Strandmark (254) ; Mat- 

 tirolo (401); Harz (99, 2:751. /. 36-38); Holfert 

 (116); Kayser (386). 



The light lines in Convolvulaceae are very distinct. They 

 are shown and described by Kayser, Strandmark, Harz, and 

 Mattirolo. The hard seeds of Ipomoea Tuba are provided with 

 two lines, one occurring underneath the exterior wall. The 

 light line is followed by a somewhat darker band in which en- 

 larged pores and a central cell-cavity occur. The darkness is 

 due to contained air. Below this the cell-cavity enlarges. 

 On the addition of chlor-iodide of zinc, the light line colors 



