184 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I40 



1942. In contrast, two tip flushes may be of unequal length as in Con 

 T 2 where they were 11.5 cm. and 2.3 cm., or they may be of ap- 

 proximately the same length as seen in Con T i-ii to 1-14. One 

 branch of a peach tree (WPe 1-4), at the border of the District of 

 Columbia in Maryland, set three successive terminal buds before it 

 ceased growth for the season of 1944. The three tip flushes were, in 

 an outward direction, 12.5, 14.0, and 11. 5 cm. long. 



The matter goes farther. Terminal bud scale scars represent a 

 final step in the transition from growth slowdown to cessation of tip 

 elongation. Before the final stage, there are all degress of slowdown 

 from continuous growth to complete cessation one or more times dur- 

 ing a single season. With angiosperms, the evidence rests not only 

 upon periodic measurement and close observation but also upon the 

 lessened distance between leaf scars. With gymnosperms, especially 

 the pines, the evidence rests not upon leaf scars but upon a succession 

 of bare-needle zones. Details will be given later in this section. 



Correspondence of diameter flushes zvith tip flushes. — No mention 

 would be necessary if this were a one-to-one relationship. The fol- 

 lowing is a list of possible correspondence with a minimum of com- 

 plexity : 



1. One diameter flush to one tip flush. 



2. One diameter flush to two tip flushes. 



3. Two diameter flushes to one tip flush. 



4. Two diameter flushes to two tip flushes. 



5. Multiple diameter flushes to muhiple tip flushes. 



A few examples of each type are given below. 



1. Of this type, illustrations have been detailed previously. It is, no 

 doubt, the most prevalent. 



2. In consideration of the apparently high incidence of multiple tip 

 flushes under certain cUmates, one is surprised to learn, from all the 

 materials at hand, that single diameter flushes for multiple tip flushes 

 occur more rarely than multiple diameter flushes for single tip flushes. 



-2 tfs 



