1861.] ADDENDA TO THE FLORA OF HARROW. 203 



that only one mark was used to indicate plants of doubtful 

 origin; and that doubt was only expressed in the case of plants 

 likely to have been purposely introduced, except in the case of 

 the Anacharis Alsinastr'um. 



Corydalis lutea was originally printed with an asterisk, which 

 was overlooked in the reprint. This small defect was counter- 

 balanced by several original typographical errors corrected in the 

 reprint. 



Coronopus didijma was an error of memory, and, without 

 reference to an authority, was set down as the name of the more 

 common C. Ruellii. 



Barbarea arcuata has been compared with a plant so labelled 

 from Loughall, county of Armagh, A. G. More, and appears to 

 be identical with it. 



Sinapis nigra. Not found ; set down in error. 



Rosa villosa, I believe rightly named. Examples were distri- 

 buted last year through the Thirsk Club. 



Cratcegus monogyna. Inserted only as a variety. 



Ribes rubrum and R. Grossularia, apparently wild, but in a 

 locality that admits of doubt. How can it be known, with respect 

 to most plants, whether they are of truly spontaneous growth in 

 any particular locality, or have been accidentally introduced ? 



Viburnum Opulus and V. Lantana occur in the neighbourhood, 

 under very different conditions of locality, etc., giving to the 

 latter every probability of spontaneous growth, and to the for- 

 mer no more than a bare possibility. Hypericum hirsutum, 

 Bryonia dioica, Plantago media, and Sison Amomum, I have 

 found plentifully in several neighbourhoods where the calcareous 

 element in the soil is very small indeed. 



Tragopogon porrifolius I do not consider indigenous. It was 

 found last year in a new locality, but evidently of accidental 

 growth. 



Arctium. Very few plants of Arctium were found in flower 

 in this neighbourhood in 1859, and those few all A. majus. 

 Yet it appears from the search made last year that A. minus is 

 the more common plant of the district. 



Vinca minor. Found in a new locality last year; yet still 

 of a doubt. 



Verbascum Thapsus. Doubtful, though it occurs where it 

 could not have been planted either for ornament or use. 



