302 THE JOURJ^AL OF BOTANY 



between 1150 and 1300 a.d, ; Ipomcea Batatas about 1300 ; Colo- 

 casia antiquorum and Cordyline termiiialis about 1400, or, accord- 

 ing to another legend, about five hundred years ago, at which date 

 Corynocarpus Icsvigata was also introduced. Mr. Thomson gives a 

 short account of the various visits to the islands subsequently to 

 Cook, whereby many of the European weeds of cultivation were 

 brought in : the chief period of introduction seems to have been 

 between 1800 and 1820. 



Mr. Thomson has adopted Mr. Cheeseman's Manual of the Neva 

 Zealand Flora (1906) as his standard of reference, but has also 

 consulted Dr. Cockayne's various papers and those of other authors. 

 The first list of introductions is that in J. D. Hooker's Handbook 

 (1867), which enumerates 165 species. In the volume under notice, 

 over 600 species are entered as introductions, though not all have 

 established themselves. Of these, 370 are British, exclusive of those 

 which figure in our own floras as introduced species ; the representa- 

 tion of British species is sometimes very complete, thus all the 

 British Buttercups and most of the British Caryophyllacece are 

 included. To most of the names interesting notes are appended, 

 relating to local distribution, methods of distribution, insect visitors, 

 and the like, with dates of first record of appearance Avhen that can 

 be ascertained. From these notes, in so far as they relate to British 

 species, we select the following points. 



There is an interesting account of the rapid establishment and 

 development of the Watercress, which was probabl}'' introduced soon 

 after the settlement of Canterbury in 1850 ; in that district plants 

 attained 14 feet in length and were stout in proportion, but the size 

 is now quite normal. Mr. Thompson tells us that in narrow streams 

 with a good flow of water, " Elodea canadensis tends to displace it ; 

 and I have noticed in some parts of the Avon at Christchurch, and 

 in tributary streams, that a species of Nitella can strangle both of 

 them. But Avatching shallow ponds near Dunedin, I have noticed 

 that, unless kept severely in check, the water-cress can put Elodea^ 

 Aponogeton and species of Nymplicea right out of competition in a 

 jviar or two." 



The Cabbage, Turnip, and probably the Swede were introduced by 

 Cook ; the two former speedily established themselves — the Cabbage 

 in 1839 *' covered the sides of the hills with a yellow carpet." A 

 remarkable form of Avild turnip, which Mr. Thomson suggests 

 may be a hybrid between the Swede and the Turnip, grows five and 

 six feet high, " w^ith heavy branching stems and leaves from two to 

 three feet long ; it never forms any bulb, but has a thick stem as 

 much as three inches or more diameter at the base." The relation 

 between Bed Clover and humble-bees is well known. Wallace's 

 statement that White Clover "even destroyed P7/orm/ww /«°^rt'^" was 

 " based on defective information " and is indeed inaccurate. The Peach 

 was introduced in 1814 : " the Maoris soon scattered the seed far 

 and wide, so that it early established itself as a wild species, for thej 

 shifted their cultivation frequently." 



The account of the Sweet-briar is interesting. " The early settlers 

 everywhere planted this favourite shrub as a hedge plant, and every- 



