BY W. r. BLAKELY. 13 



also are the seeds, while the visciu does not appear to be as durable and the 

 radicle is not quite as strong; therefore, it is probably less adapted for effecting 

 an infection in certain hosts. Apparently the Eucalyptxis is one of these, al- 

 though I have never attempted the germination of its seeds upon the Eticalypttis. 



Certain hosts, because of their thick deciduous bark, are very largely im- 

 mune from the attack of the parasites, and, unless the young radicle has made 

 good during the season before the host commences to shed its bark, and had 

 penetrated well beyond the deciduous cortical layer, it stands a chance of being 

 carried away with it. 



Such host plants as Eucalyptus punctata ha.ve the class of bark alluded to, 

 but the species does not appear to be capable of warding oft' all attacks; never- 

 theless, the percentag-e of Loranthus found parasitic upon it is exceedingly small. 

 PhrygilantJius eucalyptifoliiis is occasionally successful in effecting a union with 

 it, but I look upon that species as the most tenacious and aggressive of all the 

 Australian Loranthaoeae, as it is capable of adapting itself to almost any host 

 under tiying conditions. Next to it in vitality is Loranthus vitellinus, which 

 • has rather large fruits, and whose seeds are amply supplied with viscin and 

 albumen, which enable it to establish itself upon many kinds of host. On some 

 of the Ironbarks, Eucalyptus paniculata for instance, large clumps of Phrygilan- 

 tJius eucalyptif alius are often seen, indicating that they were attacked at an 

 tarly age, as it is quite a difileult matter for the young radicle to penetrate the 

 hai-d, composite, kino-like bark, whicli affords little or no nutriment to it, and 

 99 per cent, of the seeds that fall upon the hard bark fail to obtain an ad- 

 hesion. It is upon the young tender branches, or in the furrows of the semi- 

 hard bark that the young plants are best able to thrive. Besides the ordinary' 

 or single adhesion we have what is called "double or secondary" parasitism, 

 which is a very common form, and many interesting examples can be seen in 

 the field in places where the parasites ai'e plentiful. The most notable on re- 

 cord is that recorded by Mr. J. J. Fletcher (These Proc, xxx., 1905 (1906), p. 

 489) as follows: "Mr. Fletcher exhibited eleven branches or parts of stems — 

 being portion of eight individual plants of Loranthus celastroides, parasitic upon 

 four Eucalypti; two Angophoras, a Quince tree, and a Pinus insignis. These 

 eight Loranths had been ^'ictimised in their turn by seventeen Loranths (shown 

 in situ upon the host-Loranths) referable to three species." 



I have noticed that with plants of Phrygilanthus eucalyptif olius in the 

 Botanic Gardens, Sydney, both on Eucalyptus tereticornis Sm. and E. melano- 

 phloia F. V. M., secondary or self parasitism results in a much shorter and more 

 erect growth instead of the long pendulous branches so common to this species. 

 Loranthus was proclaimed a noxious plant in Victoria in 1904, which accounts 

 for its absence in some districts. Mr. D. W. Shiress, after a recent visit to Vic- 

 toria, informed me that the Loranth is almost stamped out, and that during his 

 two week's stay in the Bendigo district he saw but two plants. 

 Adventitious Roots. 



Adventitious roots occur on all the species of Phrygilanthus found in Aus- 

 tralia, and also upon some species of Loranthus. The ramifications of the root 

 structure are similar in both genera. The union with the host in some species 

 gives rise to numerous red-brown adventitious roots which, in nearly all cases, 

 take a downward course. The chief purpose of these roots appears to be to 

 give greater support and stability to the plant, for, by becoming attached to 

 the cambium of the host, they draw from it. through their liaustoria, most of the 

 essential food that the parent plant requires. 



