72 MINNESOTA BOTANICAL STUDIES. 



cotyledons are oval ; when fully open they have a petiole 2 mm. 

 long and blade 8 mm. long and 5 mm. broad, very slightly 

 notched at the apex. When they first emerge from the seed 

 coat the leaves are not over 5 mm. in length. 



The first foliage leaves are opposite ; they are petiolate, nar- 

 rowly ovate, serrate, slightly heart-shaped at base and more 

 nearly entire than the later leaves which are alternate, long- 

 petioled, serrate and frequently more or less two- or three- 

 lobed or parted. Usually about the close of the second sea- 

 son the well-known peculiar characteristic leaves make their 

 appearance. 



MAGNOLIACE^E. 

 Liriodendron tulipifera LINN. 



The seeds of the " tulip tree " germinate in from four to six 

 weeks after planting. The wing-like pericarp remains in the 

 soil. 



The cotyledons when they first appear are about 7 mm. long 

 and 5 mm. broad, almost sessile, ovate-oblong in shape. Before 

 the first leaf appears each cotyledon has developed a distinct 

 petiole 2 or 3 mm. long, while the blade is about 12 mm. in 

 length. 



The foliage leaves are alternate. The first is broadly ovate- 

 oblong, petiolate, emarginate, with entire margin. The second 

 and third resemble the first. The characteristic leaves appear 

 toward the close of the first season or not till the second year. 

 The epicotyl is extremely short, 12 mm. long. Succeeding 

 internodes are likewise short. 



CALYCANTHACE^E. 

 Butneria florida (LINN.) KEARNEY. 



This is the familiar "sweet-scented shrub" commonly culti- 

 vated in the eastern United States. It is native from Virginia 

 to the Gulf of Mexico. The seeds require a month or more to 

 germinate. The cotyledons are rolled longitudinally about 

 each other in the seed and remain rolled up for two or three 

 days after appearing above ground. 



The hypocotyl is stout, 20 mm. long. Cotyledons are thick, 

 dark green, slightly auriculate at base, petiolate, generally 

 somewhat trapezoidal, the apex broadly incurved. They are at 



