12 THE LOKANTHACEAE OF AUSTB^VLIA^ 1., 



It was tliougbt at one time that the Loranth would only grow on certain 

 hosts, but such is not the ease. There are, however, some instances when the 

 parasite is more prevalent on some host than others. For example, L. Gaudic- 

 haudi is invariably parasitic on Melaleuca parviflora Lindl. while L. No. 23, 

 n.sp. appears to prefer Brachychiton Gregorii P. v. M. If these species were 

 thoroughly investigated in the field, they would, in all probability, be found on 

 other plants as well, and probably good reasons for their apparently preferen- 

 tial choice of hosts would be found. For a long time I had been puzzled by the 

 frequency of L. vitelUniis upon the Bloodwood, Eucalyptus corymbosa Sm., in 

 the Hornsby (Sydney) district, and, after careful observations, I have attributed 

 it to the Harmonious Thrush, Colluricincla harmonica, and the Blue Jay, Cora- 

 cina robusta. These birds feed upon the fruits of the Loranth and also upon 

 the beetles and other insects which visit the blossoms of the Bloodwood. In tliis 

 case the food assortment of these birds is the accidental factor which accounts 

 for association of the Loranth with the Bloodwood, as the parasite is usually in 

 ripe fruit when the Bloodwood is in full blossom. 



Besides the foregoing there are other examples of what might he termed 

 preferential parasitism, for which it is most difficult to find a satisfactory reason, 

 iis in the following cases: 



On the Pennant Hills Road, Normanhurst, Sydney, Plirygilantlius celas- 

 troides, P. eucalyptifoUus and Loranthus vitellinus smothered five plants of 

 Photin/ia serriilata. Other plants in the vicinity, though older and more sappy 

 tlian the Photinia, were quite free from the parasites. It is interesting to note 

 that none of the plants that were free from the mistletoe were berry-bearing 

 species. They were Tristama conferta, Eucalyptus resinifera, Jacaranda ovali- 

 folia and Erythrina indica. 



In the Botanic Gardens, Sydney, the Planes, Platanus orientalis, are in- 

 fested with Phrygilanthtts oelastroides, and a few plants of P. eucalyptifoUus 

 and Loranthus congener, while on either side of the Planes the Willows, Salix 

 babylonica, are quite free from the parasites, notwithstanding the fact that the 

 branches of the Planes almost touch those of the Willows. 



Another ease in point, is that of Loranthus congener Sieb. In the vicinity 

 of Bobbin Head, near Sydney, Casuarina suberosa is the common host of that 

 species, while plants of Casuarina glauca Sieb., which fringe the salt waters of 

 Cowan Creek, and in many places are only a few feet away from the infested 

 trees of C. suberosa, are entirely free from the parasite. Yet, in other localities, 

 L. congener has been found parasitic on Casuarina glauca. 



The same phenomenon also applies, in the same locality and extending 

 along the water front as far as Windybank's boat sheds, to Phrygilanthus 

 celastroides , which is fairly common on Casuarina suberosa and only occasionally 

 parasitic on C. toridosa, but I have never yet found it on C. glauca, although I 

 have been constantly on the lookout for it for three years. On several occasions 

 I have seen the branches of C. torulosa and C. suberosa mingled with those of 

 C. glauca, and the former laden with the parasite, but not a trace of it could 

 be found on the latter. Those who are acquainted with the two trees would 

 readily admit that C. glauca, with its thinner bark, which is also less corky, 

 would appear to offer more inducement to the parasite than either of its con- 

 geners. I have also noticed that Phrygilanthus celastroides appears to have a 

 decided dislike to the Eucalyptus, or is incapable of effecting a union with it in 

 the majority of cases. On the other band, its congener P. eucalyptifoUus is just 

 the reverse. Tlie fruits of the former are smaller than those of the latter, as 



