Chapter XII 



MONOCOTYLEDONS AND FERNS 

 MONOCOTYLEDONS 



HYDROCHARIDE^E 



Elodea canadensis (Anacharis canadensis), Planch. 



Canadian Water-thyme 



According to Armstrong (who wrote in 1871) this species was 

 introduced in 1868 by the Canterbury Society, and put into their 

 ponds, from whence it escaped into the Avon. It was brought over 

 from Tasmania at various times in the water containing perch, tench 

 and goldfish, and was also sent over to the Society by Mr Morton 

 Allport of Hobart "as a valuable pond-weed for fish." Only female 

 plants were introduced, but it spreads by portions of the stem, and 

 is now abundant throughout New Zealand. In the Avon at the present 

 time (1916) it is being strangled in many parts by a species of Nitella. 



Vallisneria spiralis, Linn. 



This was first introduced into Canterbury by Mr A. M. Johnson 

 in 1864. In 1885, Mr E. Bartley introduced it from Melbourne to 

 Auckland, and placed some in Lake Takapuna, where it soon in- 

 creased, and became a very serious pest. Fortunately it does not 

 seed, as only one sex the female was introduced. This is the case 

 also in Australia. 



Ottelia ovalifolia, L. Rich. 



This species was first observed by Cheeseman in 1897 in ponds 

 near Manakau Harbour, but whether brought purposely from Australia 

 or introduced by accident, is not known. It is now found in lakes, 

 ponds and streams in the Auckland district, and I have met with 

 it at Hawera. It is becoming a very serious pest in the Waikato. 



SCITAMINE^) 



Canna indica, Linn. Indian Shot 



First recorded by Cheeseman in 1882 as a garden escape of 

 moderately frequent occurrence in Auckland Province. The same 

 report appears in the Manual, 1906. 



