870 



ALIEN PLANTS NEAR WOOLWICH* 



the Clunie plants) setose involucre. All the seedlings I have raised 

 produce abortive flowers, stylose if they open at all, but usually 

 withering in the bud stage. The specimens sent me by Dr. White 

 are also stylose. At Braemar it grows associated with ordinary 



Friesii, croeatum, Eitpatorium, prenanthoides, &c, and was found 

 amongst much the same company in the Perthshire stations. Dr. 

 Lindeberg wrote in 1887, "Ab Hieracii Friesii periclinio pilis 

 glandulisque dense vestito, ut propria species facile separandura." 

 I strongly suspect the plant is a hybrid, but have insufficient 

 evidence to warrant my designating it as such, and I therefore treat 

 it as a marked variety, to which distinction it is certainly entitled. 

 Whatever doubt may attach to the question of the hybridity of 

 the last, I entertain little or none respecting the hybrid origin of 

 the following. Actual proof would be a matter of the greatest 

 difficulty, if not impossibility, for we cannot artificially cross- 

 fertilise a Hieracium with the comparative ease with which a Salix 

 or Epilobhvm may be so treated, and as recent numbers of this 

 Journal show that there are those who refuse to believe in the 

 existence of hybrids even amongst plants of these genera, I give up 

 as hopeless the task of endeavouring to convince such that they 

 exist amongst Hieracia. One can only be guided by the evidence 

 of one's senses, the surroundings of the specimen, its intermediate 

 characters, the extent of its range, sterility, abortion, &c. A 

 lengthy communication from Dr. Lindeberg on this interesting 

 subject may be thus briefly summarised— hybrids among Hieracia 

 unquestionably exist, but they are rare. I hope I may be able to 

 deal with this question at greater length when the introduction to 

 my Monograph comes to be written. 



(To be continued.) 



ALIEN PLANTS NEAR WOOLWICH. 



By Capt. A. H. Wolley Dod. 



Woolwich Aksenal is a specially favourable locality for the 

 appearance of alien plants, as, being enclosed ground, it is free 

 from tbe depredations of collectors, so that plants once established 

 have a very fair chance of remaining; and although the constant 

 erection of new buildings in some of the best localities covers up 

 some, others frequently appear on the soil which is turned for 

 foundations. I have included in the following list plants gathered 

 at the Southern Sewer outfall at Crossness, where a large piece of 

 ground is enclosed as a receptacle for Thames mud ; one or two 

 gathered at the entrance to the Docks on the other side of the river 

 (this is nominally in Kent, though geographically Essex) ; and a 

 few trom the old disused brickfields in Plum Lane, Plumstead, and in 

 Wicknani Lane. No doubt the list might be considerably extended, 

 as new plants are constantly turning up. I have not thought it 

 desirable, however, to include such common rubbish-heap plants 

 as Lmum untatusimum, Erigeron canadmse (very abundant in the 



