STRUCTURE 
19 
chaffy-textured scales. Sometimes it is extremely brittle 
and herbaceous, and sometimes tough. Amongst the most 
beautiful forms of the stipes in Ferns are those which are 
clothed with scales. Occasionally they are so thickly covered 
that when they grow up in a close circlet around the crown 
they give a curios cup-shaped appearance to the plant, the 
inside of the cup being a mass of downy scales. The stipes 
tapers from its base, the rachis also getting smaller towards 
the apex of the leafy portion of the frond. Both consist 
generally of tissue — in fibro -vascular bundles — which is 
mostly of a very succulent nature. 
We uow come to the leafy, or most beautiful and graceful, 
part of the frond. Here, in the form and colouring of the 
various species, we find almost infinite variations. The 
explanation of all the differences observable in these ex- 
quisite organs of Ferns would fill a large volume. Some- 
times the leafy portion of a frond is simple and undivided 
in form, presenting the appearance of an even-edged leaf. 
Sometimes the leafy portion, though undivided, has its 
margin beautifully cut in, or indented, the indentation 
assuming various shapes, often being deeply incised. In 
other cases the incisions reach down to the rachis, or mid-rib, 
of the frond. From this form there is an almost infinite 
variety of divisions of the frond, the rachis, or mid-rib, 
giving origin to secondary mid-ribs, and these to others 
branching from them, and so on, each mid-rib bearing its 
leaflet, or series of leaflets, and the leaflets bearing their 
more or less indented lobes. 
The various divisions of the fronds of Ferns can, however, 
be most readily understood by the use of two or three simple 
terms applied in the descriptions of botanists. Where a frond 
is a single undivided leaf, without any indentations in its 
margin, it is termed simple. If it has a single leaf, deeply 
incised, but the incisions not reaching down to the rachis, 
c 2 
