A SPLENIUM . 
91 
Asplenium viride is not a difficult fern to grow if it be planted in a light soil and a 
moist atmosphere ; but it does not take kindly to cultivation, and is not always an attractive- 
looking object in cultivation. It is propagated by division of the crowns of the roots. “A 
compost, consisting of chips of micaceous rock, sand, peat, and a slight admixture of thoroughly 
decayed leaf-mould, seems best adapted to its requirements ; it also needs good drainage, and 
likes to be covered with a bell-glass.” * 
Between this species and the next (A. Trichoinanes) may fitly be placed a plant which partakes 
of the characters of both, and is probably a hybrid 
between them. It is found upon serpentine rocks 
in Moravia, Saxony, and Northern Bohemia, and 
was described by Milde under the name of A. 
adulterinum. It resembles A. viride in the texture 
of the fronds, which is softer than A. Trichoinanes , 
and also in the absence of any wing to the rachis, 
while its relationship to the English Maidenhair is 
shown in the placing of the spores, and also in the 
colour of the greater portion of the rachis, which 
is dark brown or black, although in the upper 
portion it becomes green, showing that the mixture 
of the two species has been very complete. Some 
German botanists, however, regard it as a distinct 
species. Another hybrid having A. Trichoinanes for 
one of its parents is A. dolosum of Milde, of which 
we shall speak further when describing A. Adiantum- 
nigrum, its other parent. Hybrids among ferns 
are not, perhaps, very uncommon ; the beautiful Adiantum Farleyense (see p. 43) is sup- 
posed by some to have been thus produced, and among the “ Gold and Silver Ferns ” 
( Gyinnogrannna ) they are said to be very frequent. A good deal of interesting information 
upon the subject of hybridity in connection with ferns will be found in Mr. F. W. Burbidge’s 
instructive volume upon “Cultivated Plants,” pp. 308 — 312. The author points out that “a 
clever and a careful manipulator might be able to produce hybrid ferns by removing the 
antherozoids f by means of a drop of water on the hair-like point of a sable brush, and 
applying them to the archegonia or female ovary-like cells of another species ; ” and he cites 
a large number of cases in which hybridisation is thought to have occurred. Among these 
is another member of the genus Asplenium (A. ebenoides), which is thought to be a natural 
hybrid between A. ebeneuin, a common North American species, and Camptosorus rhizophyllus 
(see p. 65). It has been found in very small quantity growing with the two ferns named 
on limestone cliffs on the Schuylkill river, near Philadelphia. One or two other actual or probable 
hybrids among the European species of Asplenium will be referred to later on. The subject 
of hybridity in ferns would certainly repay any attention bestowed upon it, and if a series of 
careful experiments were undertaken, the results would be interesting, and probably new. 
* Newman’s “ History of British Ferns.” 
t Or spermatozoids. See pp. viii.-ix. of Introduction for an explanation of these terms. 
