GERMINATION OF TREES AND SHRUBS 



329 



moss germinated 4 per cent. Germination is liypogaeous. Radi- 

 cle pushes down, followed in a few days by appearance of plum- 

 ule. Stem smooth, leaves of plumule distinctly veined, 3-lobed,, 

 lobes curled in at first; numerous hairs on the veins of the 

 upper surface ; on lower surface scattered hairs. 



Acer saccJiarum Llarsh. Sugar or Rock Maple. The seeds 

 M'^ere collected for the department of botany, November 8, 1917, 



Fig. 101. 



Fig. 102 Fig. 103 



-Trichomes from leaf of Acer nir/rum. DrawTi by C. M. King. 



Fig. 102. — Acer nigrunv seedling, showing cotyledons, plumule and radicle. 

 Drawn by C. M. King. 



Fig. 103. — Seedlings of Acer negundo, sliowing cotyledons, plumule and 

 radicle. Drawn by C. M. King. 



by Mrs. Tuttle, Osage, Iowa. They were placed for stratifica- 

 tion in humus in cold frame and covered with straw-filled manure 

 on November 11, 1917. The seeds were taken from the bed 

 JMarch 14 and planted in humus in the gi'eenhouse. The first 

 seed germinated March 24, 1918, germination in all 80 per cent. 

 Germination is epiga?ous. The smooth, grayish and slightly 

 curved caulicle first pushes out. The cotyledons, which are 



