2 14 The Ottawa Naturalist. [March 



Tlie burdock and " be^fgar ticks" were of the same character 

 and were also limited in their distribution. As a contrast to tnis 

 Prof. Macoun mentioned the mustard family as a weed producer and 

 showed that this order had no special means of dispersing its seeds, 

 and yet the'worst weeds we had belonged to this family. Another 

 animated discussion took place and the conclusion was reached 

 that the Cruciferce produced great numbers of small seeds that 

 could Hi in the ground for years, and germinate just when the 

 right conditions existed. It was shown by Mr. Hamilton that 

 seeds^of Polygonum must have lain in the soil in Montreal for at 

 least 30 years. Earth which had been thrown out when making 

 a drain produced a full crop, although for 30 years it had been 

 covered by a building. Dr. Fletcher mentioned the case of 

 Thlaspi arvense in Manitoba, which appears just when it is suited 

 with the conditions and when its chances are poor it disappers. 



Many side issues were introduced and discussed, and the 

 general opinion was reached that weeds like the house sparrows 

 had been battling for centuries against all manner of adverse cir- 

 cumstances, and on this account were better able to succeed in 

 the battle of life than our native plants, which never had any 

 trouble to overcome, hence when their environment is disturbed 

 they fade and die and only live in the memory of woodland 

 dreamers. Amongst other subjects discussed was the modes ot 

 dispersal of Nasturtium officinale, and it was decided that seeds 

 were only secondary in this. This led to talk of other members 

 of the same genus and Dr. Fletcher cited A^. lacustre, which formed 

 little rosettes in the autumn. Another member mentioned the 

 bladder wort, and explained how the extreme tips of the stems 

 fell into the mud after the first frost and became the new plants 

 the next season. In a lew words Prof. Macoun showed that 

 nature never failed in its work, that when the seeds could not 

 ripen they formed buds or bulblets, that the tips of many plants 

 ceased to grow in the late summer and the plant stored up in 

 them concentrated food. These tips sank to the bottom of stream 

 or pond and became the new plant in the spring. 



