376 DICOTYLEDONS AND CONIFERS 



found in every part of New Zealand. It is very liable to be attacked 

 by a fungoid parasite, Cystopus Candidas, the so-called white rust 

 which spreads to cabbages and other cultivated crucifers. It is also 

 a carrier of club-root. (FL, Sept. to April.) 



(Kerner states that an average-sized plant produces 64,000 seeds 

 in a year.) The seeds emit mucus when moistened, and so may adhere 

 to feathers of birds, etc. 



Dr Cockayne says of this species that it is very variable in its 

 natural habitat, and has already given rise to certain mutants. In 

 New Zealand it varies to an astonishing degree, especially in highly 

 manured ground. 



Senebiera didyma, Pers. Wart- cress 



An early introduction, first recorded by Hooker (as S. pinnatifida) 

 in 1864. A most abundant weed in all parts of New Zealand, especi- 

 ally common in waste ground near the sea. (FL, Dec. to Feb.) 



Coronopus procumbens, Gilib (Senebiera Coronopus, Poir.). 



Wart-cress, Hog's-cress 



Another early introduction; also recorded in 1864 for the first 

 time. Very common in waste places in both islands. (Fl., Nov. to 



April.) 



Lepidium Draba, Linn. Hoary-cress 



First noted by the author in 1895, as occurring abundantly on 

 Morven Hills Station, Otago. Also recorded from Ashburton by 

 W. W. Smith. I have received specimens from J. B. Armstrong 

 (1919), who informs me that it occurs in cultivated land near Christ- 

 church, where it is a troublesome weed on account of its underground 

 running stems. 



Lepidium campestre, R. Br. Field- cress ; Pepperwort 

 First recorded from the Taieri Plain, Otago, in 1873, by the 

 author. Cheeseman (1906) reports it as occurring in cultivated fields 

 and waste places in both islands, but not common. 



Lepidium hirtum, Sm. 



First recorded in 1882 as L. Smithit, Hook., by Cheeseman, as 

 occurring in pastures near Alexandra, in the Waikato. It was very 

 common in Southland in 1900; and in the Manual (1906) is stated 

 to occur in both islands in cultivated fields, roadsides, etc., but local. 

 (Fl., Dec. to Jan.) 



Lepidium ruderale, Linn. Narrow-leaved Cress; Sheep's Cress 



First recorded in Hooker's list in 1864. Stated by Kirk to be very 

 common in the vicinity of every township in the Waikato in 1870. 



