124 Taylor — A Morphological and Cytological 



Acer pseudo-platanus was studied with respect to both the 

 vegetative and reduced counts, with the result that twenty-six 

 and fifty-two were found to be the ix and 2x numbers. The 

 root-tips of this species furnished especially favorable material 

 for counting, and no significant variations appeared (Figs. 

 63-66). 



The Sugar Maple, Acer saccharum, showed few and large 

 chromosomes, thirteen being the observed ix number (Figs. 

 69-71). 



Only one of the remarkable oriental maples, Acer carpini- 

 folium, will be noted here. This has, as the name indicates, 

 leaves resembling the Hornbeam, Carpinus. This condition 

 made it of interest to obtain a count, and the results indicate 

 that fifty-two is the probable somatic number in this case, as 

 in the last (Figs. 67, 68). The group was not shown to be 

 strikingly different cytologically, therefore, from the forms with 

 lobed leaves. 



Because the rapidity with which the pollen maturation of 

 the Silver Maple occurred in the fall was unexpected, the writer 

 failed to obtain reduction division material that would furnish 

 the ix count. In a pollen grain a countable anaphase polar 

 view was however obtained, the two plates giving in one case a 

 clear twenty-six and in the other a more uncertain twenty- 

 seven as the chromosome number (Fig. 73). Germination of 

 the seeds gave material for the 2x count, which was determined 

 to be between fifty-one and fifty-five, in all probability fifty- 

 two as in the preceding cases (Figs. 72, 75). The plates and the 

 individual chromosomes of this species are the smallest observed, 

 if the number involved is considered. In two roots of this 

 form, Acer saccharinum, cases were found where the chromosome 

 number, while too great to be exactly determined, approxi- 

 mated a 4X condition at metaphase (Fig. 74). Most of the 

 plates in these roots were of the normal type, indicating that 

 this was an individual cell variation, probably by lack of separa- 

 tion of the daughter groups at the metaphase of a former divi- 

 sion. A condition believed to be similar, but not so clear, was 

 observed in the pedicels of Acer negundo. 



The most perplexing situation presented, however, is that of 

 the Red Maple, Acer rnbrum. There is but one reference to the 

 cytology of this form, a sentence in Mottier's paper on Acer 



