1918] BUCHHOLZ—PINUS 189 
Pinus Laricio, between the upper and lower tier of this stage, and 
also made a detailed study of the order and manner of develop- 
ment of walls in the proembryo, a thing which had confused many 
previous investigators. 
Coulter (8) and CouLTER and CHAMBERLAIN (9) described 
some of the early stages in the developing embryo, and, like Stras- 
BURGER, denied the existence of a true apical cell stage. They also 
stated that the lower tier of the proembryo may develop into a 
single embryo, or that the vertical rows of cells frequently become 
separated to form 4 embryos. One of these may even divide by a 
vertical wall and the 2 daughter embryonal cells become organically 
separated (8), developing subsequently as 2 separate embryos on the 
end of the same suspensor. This would give us a very fluctuating 
program of possibilities in the development of the early embryo of 
Pinus. 
SAXTON (33), in a study of the embryo of Pinus pinaster, gives 
some of the stages in the development of the embryo between the 
proembryo and the ripe seed. He concludes that an apical cell 
stage exists, which develops several segments, and in one case 
shows an embryo which he estimates as one of 30 cells, which still 
has an apical cell. He describes as anomalous some of the ordinary 
stages, and his account is rather incomplete, in many respects less 
adequate than that of STRASBURGER (38), to which he does not 
refer. Saxton also finds that “the cotyledon primordia are 
‘ exactly equal and equivalent in their origin.”’ 
Investigation 
MATERIAL AND METHOD 
The cones of Pinus Banksiana were collected from the dunes 
near Miller, Indiana, during the summers of 1914 and 1916, at 
weekly intervals during the latter part of June, July, and August. 
Cones of P. Laricio were secured from the parks in Chicago in 1914 
and 1916, and from Richmond, Indiana, in 1915. P. sylvestris 
was also secured with the Richmond collections, and P. echinata 
was collected at Conway, Arkansas, during the summers of 1914 
and 1915. 
