234 



The Botanical Gazette. [August, 



abandoned. There is much danger of new weeds being 

 introduced with the seeds or roots of plants received upon 

 the farm from the Patent Office and elsewhere. Those weeds 

 which give the most trouble are barn grass, rag-weed, purs- 

 lane and couch or witch grass. The number of species in 

 the College herbarium is 316, representing 66 orders. Inis 

 does not include several >pecies undetermined, nor the Com- 

 posite, Salices, Juncacea^, Cyperacea^, and Graminese, and 

 only a portion of the higher Cryptogams. The actual 

 number of species observed, aside from the families men- 

 tioned, is 455. 



OronOj Maine, i8j2. 



BRIEFER ARTICEES. 



Notes on the pollination of Helirtiithus .— Having had growing in my 



room for some months a specimerTof Hehanthus annuus, I have ob- 

 served its habits closely to see if I could find something new or in- 

 teresting. Nothing out of the ordinary was observed until it came to 

 bloom, which it did in March, bearing a single head. During this 

 period I observed it very closely, from the time of the opening of the 

 first disk floret until the last had withered away. Most of the flowers 

 behaved in the usual way, the style pushing out the pollen from the 

 stamen tubes and cross fertilization was insured by protandry. But in 

 a number I noticed movements, to me quite new and interesting. 

 The styles in these cases appeared as usual and soon spread their 

 tips for the reception of pollen. After standing in this way for about 

 two days I was greatly surprised to see that they were being drawn 

 back into the stamen tube. This they continued to do until they 

 finally disappeared. Then the stems were forced to one side and from 

 between the filaments were seen the bent styles slowly backing out, re- 

 sembling very much the extraction of the plumule from the acorn m 

 germination. This it continued to do until the entire style was with- 

 drawn, leaving the stamens wilted and collapsed lying upon the limb 

 of the corolla. Then the style assumed an erect position, spread its 

 tips and apparently stood waiting to receive pollen. This entire act 

 was accomplished in about a dozen cases; failed to more than draw 

 back into the stamen tube in about as many more; and in two the 

 style was broken in attempting to escape. All this was observed only 



in the outer circle of tubular flowers, which preceded the others by 

 about four davs. 



