212 MISSOURI BOTANICAL GARDEN. 



1 



the usuar meteorological observations. Such attempts have 



been made from time to time in the United States, but no- 

 where appears to have been attained that perfection shown 

 by the data gathered under the auspices of the Botanical 

 ■ Club of Canada, for a great part by pupils of public schools, 

 or those published by the forest-phenological stations of Ger- 

 many. 



In regard to the plants enumerated in the distribution 

 and phenological tables following, a few points are to be noted 

 here. Some never set fruit, as Nasturtium Armoracia and 

 Apios iuherosa. Others, and this applies to the most com- 

 mon weeds, appear with varying frequency in successive 

 years. Portiilaca olcracea is very plentiful during the present 

 year as it was in 1906 while during 1907 it was far less of a 

 pest. Opposed to this is Ellisea Nyctelea which was very 

 plentiful in 1907, covering large patches to the exclusion of 

 all other species. While both in 1906 and in the spring of the 

 present year a large number of plants of this species were 

 observed, the species was by far not so abundant as during 

 the intervening year. Interesting is in this connection the 

 appearance of Commelina communis at St. Louis, this being 

 the first time it has been reported from this locality. The 

 writer first noticed the plant in his seedpans in large numbers 

 in the spring of 1908. During the previous years this had not 

 been the case, probably because only isolated individuals 

 appeared. Later in the season the plant was found as a com- 

 mon weed in various parts of the Missouri Botanical Garden. 

 Its identity with similar plants which, in lesser numbers, 

 had occurred the previous year was established through 

 some plants raised from seed obtained in one of the localities 

 during 1907. If the occurrence of the plant had been limited 

 to the Missouri Botanical Garden the explanation that there it 

 had escaped from cultivation would probably have been ac- 

 cepted as valid. But during the spring and summer of 1908 

 the appearance of the plant was noted in a number of private 

 gardens in different parts of St. Louis. Inquiry revealed the 

 fact that though in some instances the plant had been ob- 

 served during 1907 it had not been observed previously, 



Ilcncc it is probable that the plant was introduced in St. 



