TRILLIUM SP. 155 



of the Northeastern States and Canada" ascertain how one 

 not knowing the generic name of this plant would discover 

 the name and determine its classification. Determine for 

 yourself the specific name of the plant you have studied. 



ANNOTATIONS. 



In its superficial appearance Trillium is not a good 

 representative of the Monocotyledons. Most Monocotyle- 

 dons have parallel-veined leaves with sheathing bases, 

 but in this particular Trilliums are quite like the Di- 

 cotyledons. In flower and stem, however, it is a typical 

 Monocotyledon. 



In reproductive structures this plant shows a distinct 

 advance over the pine, in that there is here a true 

 "flower," i.e. groups of conspicuously colored leaves as- 

 sociated with the sporophylls. The calyx in flowers is 

 usually protective and the corolla generally supposed to 

 be a device for attraction of insects, though there 

 are many cases where the parts do not perform these 

 functions. The calyx or even foliage leaves may do 

 the work of attraction. The ovules (megasporangia) are 

 entirely enclosed by the carpels, and the microspores 

 in pollination are placed upon the specially prepared sur- 

 face of the carpel (stigma) instead of directly upon the 

 nucellus as in the pines. This necessitates much greater 

 elongation of the pollen-tube, which takes place in much 

 less time. In the pine the development of the pollen- 

 tube is accomplished in a period of twelve or thirteen 

 months, while in Trillium a very much greater distance 

 is traversed in a day or two, possibly in a few hours. 



In the pine the male gametophyte is very greatly 



