1932] Garden Pea and White Sweet Clover 81 



coats were tested with phloroglucin and HCl acid and then heated 

 to test for a paragalactan substance. No action. This would indi- 

 cate a pentose substance in the hardest part of the seed coat. 



With the above observations in mind, nearly mature and mature 

 white sweet clover seeds which were very impermeable to stains were 

 treated as above with HCl acid solution. When tested with iodine and 

 sulphuric acid and chloroiodide of zinc the domes took a very deep 

 blue color, indicating as in the garden pea the presence of a pentose. 

 The light line and the portion covering the domes were unattacked, 

 except slightly. The light line does not readily yield to hydrolysis. 



The work of Coe and Martin was confirmed as to the distance a 

 stain will penetrate a hard seed in white sweet clover. The domes 

 were readily stained to the light line but no trace of stain passed 

 into the light line. 



Pammel and others have indicated a light line in Garden Peas 

 in about the position it is commonly found in the Leguminosae. Tun- 

 mann shows a light line in the shape of a cap over the end of the 

 cell. In this work no distinct light line was observed in the Garden 

 Pea. Testing by immersion in stains showed that the impermeable 

 portion of the pea is in the cutin, since stains do not pass through 

 the cutinized layer. 



I wish to express my appreciation of the encouragement and help- 

 ful suggestions given me by Dr. J. N. Martin of the Iowa State Col- 

 lege while I pursued this work. 



Summary 



In sweet clover and garden peas the Malpighian layer of cells 

 begins to thicken very much about a week after fertilization. Thick- 

 enings are in ridges leaving crevices between. 



Sweet clover develops a light line which is more impermeable to 

 water than the outer part of the cell. The pea does not have this 

 region but in some cases had an impermeable cutin. 



Pectin is deposited in the cells around the micropyle at about the 

 time of fertilization in the garden pea. 



The outer portion of the Malpighian cells of sweet clover and gar- 

 den peas is a hemi-cellulose, very likely some form of pentose. The 

 inner portion is cellulose. 



