1892.] NATUKAL SCIENCES OF PHILADELPHIA. 449 



NOTES ON MONARDA FISTULOSA. 

 BY THOMAS MEEHAN. 



As stated in the class-books, Monarda fistulosa is a variable species. 

 A plant in my garden, originally from a shaded woodland in East- 

 ern Pennsylvania, blooms from midsummer continuously till frost. 



The midsummer heads are terminal. At the base of the common 

 peduncle is a pair of leaves with two axillary buds. These make 

 branches, and the earliest capitulum of the season stands regularly 

 in the fork made by these brasiches. 



But as these secondary branches grow and form pairs of opposite 

 leaves, only one of the axillary buds in the lower pair pushes into 

 growth. This one grows with so much vigor, that the capitulum is 

 pushed to one side, the common peduncle becomes lateral, and the 

 axillary branch becomes the leading stem. 



At the next node the same behavior prevails, but at the third 

 node both axillary buds develop, the strongest, however, assuming 

 leadership. 



The secondary branches of Monarda fishdosa, though apparently 

 forming a straight stem, are formed of axillary branches, which, 

 pushing aside the terminal common peduncles so as to make them 

 lateral, have taken the position of the leading short or central axis. 

 How this method of forming " extra axillary " inflorescence is 

 brought about, I have explained in another paper.^ 



The flowers are centripetal. It takes several weeks from the time 

 the central flowers of the capitulum open before those at the base 

 follow. At this date, October 26th, the flowers begin to open by 

 expanding the lobes of the corolla about sundown. Between 6 p. m. 

 and 9 p. m. twelve had opened. By daylight next morning, in the 

 head I had selected for observation, there were twenty-four. Eest 

 follows, and nothing more is done in this direction till nightfall 

 comes again. 



The manner of opening is exceptionally interesting. It is well to 

 examine a flower a day before it would naturally open. The long 

 hair on the upper lip may be almost termed a beard. By lightly 

 pulling this beard the flower bud is opened. The stamens are then 

 seen lying flat on the lower lip, with the lower linear lobe of this 



^Proceedings of Academy of Natural Sciences of Philadelpiiia, 1889, p. 58, 

 " On Corvdalis flavula." 



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