78 MINNESOTA BOTANICAL STUDIES. 



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

 i6 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^. 

 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, 15-20 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. 



VITACE^. 



Vitis cordifolia Miciix. 



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

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



