42 Elementary Species 



the latter part of the summer and during the 

 fall, reaching an advanced stage of development 

 of the branched stems before winter. Early in 

 the spring the flowers begin to open, but after 

 the ripening of the seeds the whole plant dies. 



The three perennial species just mentioned 

 develop in the same manner in the first year. 

 During their flowering period, however, and 

 afterwards, they produce new shoots from the 

 lower parts of the stem. They prefer dry and 

 sandy soils, often becoming covered with the 

 sand that is blown on them by the winds. They 

 are prepared for such seemingly adverse cir- 

 cumstances by the accumulation of food in the 

 older stems and by the capacity of the new 

 shoots to thrive on this food till they have be- 

 come long enough to reach the light. Once 

 more V. tricolor ammotropha was found near 

 Ystad in Sweden, and the other two forms on 

 Gotland. All three have narrowly limited habi- 

 tats. 



The typical tricolored heartsease has re- 

 mained annual in all its other subspecies. It 

 may be divided into two types in the first place : 

 V. tricolor genuina and V. tricolor versicolor. 

 Both of them have a wide distribution and seem 

 to be the prototypes from which the rarer forms 

 must have been derived. Among these latter 

 Wittrock describes several local types, which 



