Parsons : Hints on Natural Histoey Collecting. 85 



agrarian zone. The zones cannot be sharply defined, since the 

 presence or absence of the characteristic plants is greatly influenced 

 by the presence or absence of suitable soil, as well as by the aspect. 



Another point that should also be noted, although nothing but long 

 experience will enable one to give a trustworthy opinion, is the 

 " citizenship " — i.e., the degree of probability of our plant being a 

 native or introduced. There are some plants, such as the heaths, 

 furze, and daisy, which every one will admit to be true natives of our 

 island ; others, such as the celandine, the goutweed, and goose foot 

 {Chenopodimn Bonus- Henricus), are found apparently wild, but yet only 

 in the neighbourhood of houses, or in places to which they may have 

 been introduced by human agency : these are called " denizens " by 

 Mr. Watson. Another class of doubtful natives are those called 

 " colonists," which are found only in cultivated fields, and seem to 

 depend for their existence upon human agriculture. A familiar 

 example is the red poppy : 



" Poppies, 'tis known to all who rove, 

 Grow in the field, and not in the grove." 



Others are the corn cockle, the corn marigold, and the blue bottle. 

 Plants known to have been introduced, as the sweet chestnut and the 

 water thyme (Elodea canademis), are called " aliens," however firmly 

 they may have established themselves ; while those which appear 

 accidentally, and die out without establishing themselves, are called 

 " casuals," e.g, the thorn-apple and many others, which may be found 

 on ballast and rubbish heaps, and on roadsides. Young botanists are 

 usually too ready to consider every plant they find a native : caution 

 comes with age. As memory is treacherous, and life uncertain, our 

 notes should be written down at the time, and labels 'rihould be 

 authenticated with the collector's name. 



In arranging our collection in the cabinet, the rule should be to 

 group the specimens according to their natural affinities, those kinds 

 most nearly allied being placed next each other. It is necessary 

 sometimes to dejDart from this rule in the case of very large specimens 

 which the exigencies of space will not allow to be grouped with their 

 congeners. Another exception occurs in the case of fossils, which 

 Ihe usual and preferable plan is to arrange primarily in the order of 

 the strata in which they are found, the fossils of each formation being 

 separately arranged according to their natural affinities, zoological or 

 botanical. Collections from different regions may also be kept 

 separately sometimes with advantage. 



