322 PROCEEDINGS OF SECTION D. 



Of the former, and in the valley of the Yarra, near Melbourne, I have^ 

 noted the following hosts : — Acacia pycnantha A. mollissima, A. 

 implexa, Eucaljrptus leucoxylon, E. rostrata, E. viminalis, Hymenan- 

 thera Banksii, Bursaria spinosa, Myoporum viscosum, Kunzea 

 peduncularis, Exocarpus cupressiformis, E. spartea, Pomaderris 

 apetala, Rubus parvi folius, &c. ; also the introduced, acclimatised 

 and now proscribed Gorse (Ulex Europaea) through which the parasite 

 finds its way occasionally to such herbaceous dicotyledons as Rhagodia 

 nutans. 



UnUke Cuscuta, which is known to show a predilection for a 

 particular host or few hosts for nourishment, Cassytha is omnivorous. 

 In the grasp of one tangle of C. melantha I noted, among others, the 

 following hosts linked together : — Acacia pycnantha, A. implexa, 

 Bursaria spinosa, Pomaderris apetala, and Eucalyptus rostrata ; and, 

 as is the case with all such parasites, the morphological character of 

 the species did not vary in the least degree with the change of host. 

 The plant, excepting leaves and extreme ends of growing shoot, is 

 dark green, with abundant chlorophyll, and with stomata, in vertical 

 uniseriate rows, transversely set and abutting one on another. 



Large areas of oil-yielding Eucalyptus forest are infested with this 

 Cassytha, e.g., the district to the north of Bendigo, where, in places, 

 the original vegetation — comprising chiefly Eucalyptus fi-uticetorum 

 and E. viridis — is hardly visible, an intricate entanglement of vegetable 

 wirework being all that is presented to the casual view, which reminds 

 us that parasites generally spread more rapidly through a forest of one 

 or kindred species than where the forest is a mixed one. In the 

 Mallee, especially in the neighbourhood of the Pink Lakes to the north- 

 west of Ouyen, may be seen single trees or groups of trees completely 

 covered. 



In the relation of Cassytha melantha to its host the favourite 

 method of progress on a straight branch of about 0*75 cm. diameter 

 is to make about five spiral turns, during which 25 or more haustoria 

 may be produced ; next to avoid close contact with the host for a 

 distance of about 15 cm.; then to take another spiral hold of about 

 five turns, and so on until it has outgrown the host or has come in 

 contact with a fresh twig or host plant. Pfeffer's illustration^ of 

 Cuscuta shows a similar rhythmical alternation. Professor Ewart's 

 example"* of Cuscuta Epithymum shows au irregular disposition 

 and a reversed spiral. This reversal of spiral coiling I have 

 not noticed in Cassytha, nor have I detected in Cassytha melantha 

 the occurrence recorded for Cuscuta by Sachs, ^ of spirals usually 

 araduated from coils very steep below, through oblique to 

 almost horizontal coils above, due to elongation of the supporting 



