FERN GROWING 157 



on the east coast of Scotland, was much reduced In size, and the 

 Osmunda regalis on rocks dashed with waves near Santander was 

 only three or four inches in height, whilst in some parts of Ire- 

 land it attains the height of eight or ten feet. The Lady Fern 

 becomes stunted in growth on exposed mountains, and attains 

 the greatest luxuriance when growing on the margin of brooks 

 in sheltered situations. The late Sir W. J. Hooker con- 

 sidered that the growth of Adiantum Capillus- Veneris, and 

 Asplenium marinum as he found it in the Burren district 

 of County Clare, could only be compared to their luxuriance 

 in Madeira. The author in i860 gathered fronds of the 

 Maiden-hair Fern whose length was thirty inches, amongst 

 rocks on the summit of the Vilia Escusa, one of the spurs 

 of the Pyrenees in Northern Spain. 



The difference between a species and a variety is difficult 

 to denote, as there are changes from the normal form that 

 may have been occasioned by time and altered circumstances ; 

 and again, there are what may be termed the normal form 

 of a district, as a species varies in its character in different 

 places — in one place the growth is luxuriant, in another it is 

 stunted — and this frequently means a greater or less develop- 

 ment in all the details of a frond. There are places near 

 Scarborough where the Hart's-tongue exists as a dwarf, mis- 

 shapen plant ; and there are other places within a distance 

 of two or three miles where the soil is damp, and the plants 

 are protected from the sun and wind, where they assume 

 gigantic proportions ; but these divergences cannot be looked 

 upon as varieties, only as of greater or less luxuriance owing 

 to the soil and surroundings. The same reasoning equally 

 applies to other species. What we look upon as varieties are 

 confined to those where the changes are far more distinct, 

 and where the difference can be seen at a glance. 



If two species are successfully crossed, their offspring will 

 be hybrids, but not if the crosses are between two varieties 



