42 SUMMARIES OF EAST RIDING PLANTS. 



The London Catalogue, ninth edition, 1895, on which our 

 Flora is based throughout, includes for the British Isles the 

 following : viz., 98 orders, 543 genera, and 1958 species. 

 Comparing the numbers in the preceding table with those of 

 the London Catalogue, we find a high percentage of orders 

 and genera. It is in the number of species that the total 

 niaj' seem somewhat low ; we, however, must remember the 

 natu re of the physical features as described under Physiography, 

 above. General adaptability to cultivation may to some 

 extent account for any apparent paucity of species, although 

 in the case of cultivation and the extensive shipping operations 

 associated with the Humber, whilst there may be a tendency 

 to exterminate aboriginal vegetation, the loss to a greater 

 extent than is generally imagined may be made up by 

 the increased facilities for the introduction of immigrant 

 "strangers and foreigners" (aliens). 



Of the 98 orders of the London Catalogue, no fewer than 

 91 are represented in the East Riding, leaving only 7 orders 

 that are not as yet accounted for. These are the following, 

 viz. : — 



II. Frankeniaceae. 69. Santalacese. 



14. Tamariscinese. 72. Einpetracese. 



].'). Elatineae. 00. Eriocauleae. 



60. Aristolochiaceae. 



As regards the number of species, 1035 ; if we assume 

 what is scarcely warranted, namely, that the vice county has 

 been investigated as thoroughly as possible, it must appear 

 that the paucity is due to lack of variety in the physical 

 features and conditions of the land. With more thorough 

 search in every available locality the number of species given 

 above may be increased, even as regardsour native plants as 

 well as our dock waste-ground aliens. 



From personal observations made during very many 

 rambles in the East Riding, and extending over a period of 

 17 years, the comparative frequency of occurrence of the 

 species seems to work out somewhat as follows, aliens and 

 incognita being omitted : — 



Species— Very Common Generally 130 



,, Common ... ... ... ... ... ... 220 



,, Fairly Common 241 



,, Abundant in a few Localities ... ... 48 



,, Abundant Locally, or in one or two Localities 27 



,, Uncommon ... 133 



,, Rare 59 



Very Rare 20 



