GARDEN ESCAPES 



263 



usually shared by adjoining run-holders ; it is alternately kept by one 

 or the other. It was a season or two after such an overhaul by 

 Arapawanui that I first noticed tansy. As in the case of another alien 

 (Bartsia viscosa), its story is particularly easy to piece together. To 

 begin with, in the Arapawanui garden I knew amongst the pot-herbs 

 that there existed a substantial tansy plot. With this fact in mind, it 

 was not difficult to imagine the order issued as to repair of the boundary 

 fence ; to note the man shoulder his spade ; to observe the soil adhering 

 to the tool ; to visualise the tiny seed wrapt in its coatings of clay. So 

 far quite conceivably all may have happened as on former occasions 

 the order given as before, the spade as before taken from the garden, 

 with also, as before, earth and seed adhering 

 to it. Now, however, under more fortunate 

 circumstances, the earth might not, during the 

 strapping on to the saddle, during the brush- 

 ing through scrub, during preliminary repair 

 work, have become detached along a section of 

 the fence-traversing bush where the seed would 

 perish for want of light ; it might not, as before, 

 have been choked on dense sward or rotted by 

 exposure, or bitten below the crown by stock, 

 or perished by too deep burial, or been anni- 

 hilated by slugs, or washed out by torrential 

 rains, or crushed under foot, or mildewed by 

 blight, or baked by drought. Yet in these ways, 

 and a score besides, the appearance of tansy on 

 Tutira may have been for years postponed ; seed 

 may have again and again been brought up on claggy spades from 

 Arapawanui, only to perish. On former occasions there may have 

 been an excellent tilth provided, but invalidated by too deep 

 burial ; the season of the year may have been propitious, but 

 spoilt by abnormal weather. At last there had occurred a combina- 

 tion of favourable factors, resulting in the acclimatisation of a new 

 alien. Probably, of seeds that reach New Zealand, not one in ten 

 thousand succeeds in establishing itself. My tansy patch is in itself 

 an example of the particularity of certain species as to conditions 

 facilitating germination. Though every year tens of thousands of 

 winged tansy seeds are launched into the air, not a single one 



Tansy. 



