78 MINNESOTA BOTANICAL STUDIES. 



so that both are on the same side of the stem. They are about 

 16 mm. long and 8 mm. broad. 



The epicotyl often becomes greatly elongated, reaching a 

 length of 50-100 mm. Leaves are all opposite, those of the 

 seedling are the same shape as the later leaves. 



RHAMNACE.E. 

 Berchemia racemosa SIEB. & Zucc. 



This plant is a shrub with conspicuously veined leaves. It 

 is a native of Asia. The seeds require two or three weeks to 

 germinate. It is often a number of days before the cotyledons 

 get out of the seed coat which is carried above ground. 



When the cotyledons first emerge they are sessile, strap- 

 shaped, 8 mm. long and i^ mm. broad. They remain about the 

 same size for a time after they are fully open. The hypocotyl 

 is slender, about 15 mm. long. 



By the time the first foliage leaves are open the hypocotyl is 

 15-20 mm. long ; the epicotyl 5 mm. in length and the cotyledons 

 10 or 12 mm. long and 1.5-2 mm. broad. The foliage leaves 

 are ovate, petiolate, conspicuously veined ; the first two are 

 opposite or nearly so, all others are alternate. 



Rhamnus purshiana DC. 



This is a handsome tree of Pacific North America sometimes 

 planted in the eastern United States. The bark is the " Cas- 

 cara Sagrada " of the drug stores. The seeds require a month 

 or more to germinate. 



The cotyledons increase but slightly in size after opening. 

 They are obovate, entire, sessile or nearly so, 7 mm. long and 

 5 mm. broad. The hypocotyl is 25-30 mm. long. 



The epicotyl is slender, 1520 mm. long. Foliage leaves are 

 ovate, pointed, petiolate, alternate. The first two and the third 

 and fourth are, however, nearly opposite. The margin of the 

 leaf is finely serrate ; the veining very prominent. 



Vitis cordifolia MICHX. 



This is one of the commonest wild grapes found in the north- 

 ern United States. The seeds germinate readily, the cotyle- 



