I2l6 WEEDS AND PARASITIC FJ.OWERING PLANTS 



The growth of Trichoderma in starch agar, at ordinary tempera- 

 tures, averages i cm. per 15 hours; hence the rapidity of the pathological 

 process, which may bring about the death of the tree within a few days. 

 The parasite grows equalty well in any medium provided the latter does 

 not contain an excess of alkali. 



Copper sulphate in a dose of o.i % added to the agar stimulates the 

 formation of spores. A soil rich in humus and well manured promotes the 

 growth of the mycelium and the formation of the spores. The vegetative 

 body of the fungus is found in all the elements of the X3dem, from which it 

 spreads into and between the cells. It cuts off light from them entirely 

 and encroaches on and destroys the walls. 



Its property of living quite easily as a saphrophyte, and the large num- 

 ber'of spores which the wind scatters with extreme facility, render this pa- 

 rasite one of the most dangerous to the orchard, and it, is necessary to take 

 prompt and energetic control measures. 



WEEDS AND PARASITIC FLOWERING PLANTS. 



944 - Cryptostem ma calendulaceum, Crepis capillaris, Leonotodn 

 hirtus and Carduus spp., Weeds in New Zealand (i) — Atkinson e. h. in The 



Jouriuilof A^rici/Miiie, Vol. XII, Nu. i, pp. 32-34. Fig. <) ; No. 3, pp. i7,'5-i87. Fig. 6. 

 WeUington, 191 6. 



1. The Writer continues the description of the common weeds in New 

 Zealand by descrihing Cryptostemma calendulaceum {capeweed) , Crepis capil- 

 laris (hawkweed) and Leontodon hirtus (hawkbit). 



The first of these Compositae is very common in the Northern island. Is 

 has likewise been reported in numerous localities in the Southern island, 

 where it tends to invade the pastures, choking and replacing the leguminosae 

 and grasses best adapted for cattle feeding. 



The two other species also occur very widely, but they should be rather 

 considered as useless than injurious. 



2. Description of 6 species of Carduus growing more or less frequently in 

 New Zealand : C. lanceolaUis (spear thistle) ; C. nutans (nodding thistle) ; 

 C. pycnocephalus (winged thistle) ; C. arvensis (Californian thistle) ; C. 

 Marianus (milk thistle) and C. eriophorus (woolly-headed thistle). 



C. lanceolatus is certainly the species most wideh' distributed in the 

 two islands. This species is the one which imparts its characteristic appear- 

 ance to the meadow flora when vegetation grows after bush fires. C. ar- 

 vensis is also very common. C. pycnocephalus is much rarer; in certain sterile 

 and bare parts it often forms the sole winter forage for sheep. C. Maria- 

 nus abounds in several localities, but tends to disappear with the develop- 

 ment of ctiltivation. C. eriophorus only occurs along the rivers and in the 

 valleys of Wairarapa and Otaki. Finaly, C. nutans has been reported in 

 southern Canterbury and some localities of Otago. 



(i) See B. March 1916. No. 363. ■ {Ed.) 



