June, 1902.] 



Rosette Plants of Ohio. 



291 



Salsif}', and Parsnip of the garden. The natural tendency of the 

 rosette plant, in these cases, to store up food for the second 3-ear's 

 growth is taken advantage of by gardeners and a valuable food 

 plant results. 



In the temperate zone, under the favorable conditions for plant 

 growth that obtain in our State, not many perennials find it advan- 

 tageous to retain the rosette habit beyond the critical period in 

 their life history which lies between the sprouting of the seed and 

 the establishment of a strong, underground stem or root system. 

 At this period the rosette is replaced by an aerial, flowering stem 

 as, for example, with the Canada Thistle, Carduus arvensis. This 

 fact is noted by Prof. Lyster H. Dewey in Bulletin 27, Div. of 

 Bot., U. S. Dept. of Agr. He says : " Canada Thistle is usually 

 first introduced into new localities by the seed. The seed germi- 

 nates and a rosette of leaves lying almost flat on the ground is first 

 formed. * * The following year a flowering stalk branching at 

 the top grows up to a height from one to three feet (20 to loocm. ) 

 rarely higher." 



Fig. I. tr, close rosette of Oiiagra biennis ; d, open rosette of Geranium 

 carolinianum ; c, perpetual rosette of Tetraneuris acaulis. 



The perennials which retain the rosette habit throughout their 

 life histor}' may be termed perpetual rosettes. In Ohio they are 

 few in number and are mostly scapose or acaulescent plants as the 

 Dandelion, Taraxacum taraxacum ; English Daisy, Bellis peren- 

 nis ; lyakeside Daisy, Tetraneuris acaulis ; and Plantain, Plantago 

 sp. 



One group of perpetual rosettes, however, is not acaulescent, 

 having solved the problem of being low rosette plants and at the 

 same time having aerial flowering stems. This is accomplished 

 by the plant sending out lateral branches from the axils of its 

 rosette leaves. These lateral branches grow outwards and up- 

 ^vards, flowering and fruiting freely but not enough to exhaust 



