THE YOUNG NATURALIST. 



171 



the leaves are not articulated or jointed 

 to the stem so that they never fall off 

 as do the leaves of our ordinary forest 

 trees, but they wither and decay whilst 

 still attached to the stem. At the 

 extremity or growing point of the rhi- 

 zome the leaves are produced. These 

 are quite unique amongst British plants 

 and a study in themselves. In tech- 

 nical language they are described as 

 equitant and ensiform, i.e., they are 

 folded so as to embrace each other and 

 are sword-shaped. If a piece of the 

 rhizome be pulled up it will be seen 

 that a cluster of leaves arise from its 

 apex. Only one leaf springs from the 

 same apex, but as the internodes or 

 space betwixt two leaves is extremely 

 short, they are very crowded and the 

 stem lengthens slowly. Where the 

 leaves emerge they completely encircle 

 the stem, and as they are given off 

 alternately on opposite sides, the one 

 firmly clasps the other and so effectu- 

 ally shield the growing point of the 

 stem. As the rhizome is prostrate 

 whilst the leaves are erect, they are 

 sharply bent at a right angle so as to 

 rise into the air. At the base of the 

 leaves where they overlap eacli other 

 they are of a most beautiful and deli- 

 cate pink colour, and the edges are 

 thinned out to a surpassing fineness ; 

 whilst although a full-grown leaf may 

 be a quarter of an inch in thickness at 

 the centre, it is so loose and spongy in 

 texture as to be translucent. When 



cut across, the spaces between the 

 veins are seen to be empty tubes, stop- 

 ped at irregular distances by dry r 

 pith-like, cellular tissue : these extend 

 throughout its entire length, so that 

 the leaf when viewed against the light 

 seems barred with short transverse 

 dashes. If a leaf is cut off close to 

 the stem it will be seen to be folded 

 longitudinally and also somewhat keel- 

 ed on the middle of what is anatomi- 

 cally the lower or under surface, the 

 upper or inner surface being pressed 

 against the other leaves. It is quite 

 possible to spread this sheathing por- 

 tion of the leaf flat, when its two planes 

 would correspond to the surfaces of 

 ordinary leaves; but as the leaf is 

 traced upwards, the back becomes more 

 evidently keeled and sharp-edged,whilst 

 the two inner faces grow more closely 

 together, till in the upper third of its 

 length the two halves become welded 

 together into a homogenous, sharp - 

 pointed, two-edged, sword- shaped leaf. 

 The two flat surfaces are alike in every 

 way, having an equal number of sto- 

 mata on either side; but their planes 

 are vertical to the horizon and to the 

 central stem, instead of being parallel 

 and horizontal as in common leaves, 

 whilst the whole exterior of the 

 leaf has been evolved from the lower 

 surface. A very superficial exami- 

 nation of a leaf will make this plain, 

 and it is interesting as being the only 

 British plant which fully exemplifies 



