376 PROCEEDINGS OF THE ACADEMY OF [1885. 



September 8. 

 Dr. A. E. Foote in the chair. 

 Twelve persons present. 



Inflorescence of the Composite. — At the meeting of the Botan- 

 ical section, on the seventh inst., Mr. Thomas Meehan remarked 

 that it seemed obvious, by the rule in Asteraceous plants, or the 

 order Composite, that the order of anthesis was inversely to the 

 growth. But by a note of Prof. Asa Gray in his new synoptical 

 Flora of North America, referring to Liatris, it did not appear 

 to have received the marked attention of botanists. Among the 

 generic characters of Liatris, Dr. Gray gives flowering from the 

 top downwards, as in an inverted spike or raceme. He exhibited 

 specimens of Mulgedium, Lactuca, Erecthites, Gnaphalium, Aster, 

 Solidogo, Vernonia, Erigeron, Bidens, and Xanthium, all gathered 

 casually and hastily within a few yards of each other, to show 

 that the upper or terminal flower was the first to open, then the 

 upper flower on the next branch of the raceme or panicle, and 

 then the lower ones in succession. If in these plants the side 

 branches were arrested in their growth, and the terminal flowers 

 of the branchlets brought down in proximity to the main stem, 

 we had precisely the same kind of anthesis as in Liatris. If 

 Liatris had a branched panicle instead of a spicate inflorescence, 

 we should not notice an}' difference between it and other plants. 

 There were some other families of plants that presented a similar 

 order of anthesis, but it is so marked a character in Composite as 

 to make it well worthy of consideration in connection with the 

 peculiar construction of the flower heads. 



A remarkable reflection is that this completion of growth, and 

 their flowering down the stems backwards, ceases with the forma- 

 tion of the flower heads. Then the anthesis of the florets is with 

 and not reversely to the growth. In a sunflower, for instance, 

 any one may remember that the florets near the ray open first, and 

 continue to open spirally until the centre is reached. 



There were, however, exceptions in composite to the order of 

 anthesis in the flower heads. In Ambrosia the lower flowers on 

 the spike opened first, and they continued to open upwards as in 

 the raceme of any other order of plants. In the female plants of 

 Ambrosia artemisieefolia. being abundant this season (1885) the 

 truly racemose order of opening was the same as in the ordinary 

 monoecious plants. 



September 15. 



Mr. Charles Morris in the chair. 



Twenty-three persons present. 



