ADIANTUM. 



319 



This lovely species is by most growers considered difficult to manage, 

 but it is generally when kept in too warm a house or when potted in too 

 loamy a soil that it gives any trouble. To be grown successfully it only 

 requires greenhouse treatment, and it thrives best in a mixture of two parts 

 peat, one part fibrous loam, and one part coarse silver sand (or, when 

 procurable, one part of old lime rubbish, of which its roots are very fond). 



A. r. asarifolium — as-ar-if-ol'-i-um (Asarum-leaved), Willdenoiv . 



Although some authorities consider this Fern, which is very scarce, as 

 identical with A. reniforme, and make simply a variety of it, the distinguishing 

 characters which it possesses are apparently of sufficient consequence to entitle 

 it to the rank of species. Sir William Hooker, for instance, thinks that it is 

 a different plant, and he justly remarks that " A. reniforme is more slender, 

 has long, flexible stipes (stalks), is less scaty ; its fronds are smaller, and of 

 thinner texture, and they have less densely approximated involucres," which 

 means that the indusia (coverings of their spore masses) are not set so closely 

 together. For the same reasons Willdenow also considers the two plants as 

 distinct species. These reasons, however, have not proved sufficient to the 

 authors of the " Synopsis Filicum," who have retained asarifolium as a 

 variety of A. reniforme. A. r. asarifolium has an equally restricted geographical 

 range, as it is only known to occur in a wild state in the Mauritius and 

 Bourbon Islands. Whether species or variety, the general appearance of the 

 plant is somewhat near that of the species from which it is supposed to have 

 originated, but it is always stouter and coarser, and its fronds, instead of 

 being truly kidney-shaped, are orbicular (quite round) and of a much thicker 

 texture : they usually measure 2^in. across and are produced from a stout, 

 single crown, the stalks and the base of the frond itself being very woolly. 

 Lowe, in his splendid work, " Ferns British and Exotic," vol. hi., p. 8, 

 says that " Petiver describes a third very similar plant, said to have been 

 found in the Philippine Islands, and which he has called A. pkilippinense" ', 

 but other botanists having failed in their search for Petiver's plant, and 

 the numerous plant collectors who have searched for new plants all over 

 these Islands having equally failed, its existence may be considered as very 

 doubtful. — Hooker, Species Filicum, ii., p. 2, t. 71b. Nicholson, Dictionary of 

 Gardening, i., p. 28. 



