78 TRANSACTIONS AND PROCEEDINGS OF THE ([Szss. Larx/ 
confined to any part of the British Islands, or, indeed, to 
almost any part of Europe, has little prospect nowadays of 
discovering additions to the genuine native flora of the 
country, and still less of finding a species not previously 
known. Yet a herbarium, to illustrate the existing flora of 
the region, is likely to be of both interest and real value, if 
the specimens are authenticated with information of locality 
and date of collection, nature of habitat, relation to man 
(introduced, favoured or threatened by him), and relative 
frequency. Such herbaria afford records of great service for 
comparison with the flora of the same area in later years. 
All the more is this the case where human industry is rapidly 
changing the environment, both physical and organic, new 
plants, and occasionally new animals, being introduced by 
accident or intentionally, and greatly affecting the chances of 
success or failure of the native flora. 
Such a herbarium faithfully representative of the flora of 
a limited area is of more real worth than one composed of 
rare species, and is seldom liable to the charge of endangering 
the existence of rare species. 
But do even the largest and best of existing herbaria fulfil 
all that might be desired of them? The answer can scarcely 
be in the affirmative. Indeed, it is not possible for them to: 
be built up on a single ideal, composed as they are of the 
gatherings of many hands, in every part of the world, often 
brought together in great difficulties, when no choice of 
materials could be exercised. The great herbaria must 
contain much that is too precious to be thrown away, but 
that does not fit into any scheme of selection. In private 
herbaria, and in the smaller public ones, a definite plan 
should guide the selection and treatment of their contents, 
that plan differing according to whether the collection is to. 
be representative of a geographical district or of a larger or 
smaller group of plants. Within the limits determined it 
should be as nearly perfect as it can be made; that is, it 
should supply all the information that it is possible to bring 
within these limits. Reduced to definite terms this means_ 
that the aim should be to give in the herbarium, in so far as 
the conditions allow, a full and true representation of the 
life-history of each species contained in it. A few species so 
treated, and gradually added to as occasion allows, will be_ 
