ROOTS. 17 



dicotyledons from its other characteristics, and is therefore classed 

 with them. In most cases adventitious roots are fibrous, springing 

 from the unelongated radicle (young root). Roots of this kind often 

 become additionally branched by other fibres issuing from them. 

 Grasses in general have adventitious roots. 



Fig. 3. Aerial root of ivy. Other examples of this kind of root 

 are found in the mangrove, screw-pine, Moreton Bay and New South 

 Wales fig-trees. 



Fig. 4. Fibrous root of kangaroo-grass. This description of root 

 is generally stringy or thread-like. Most annuals have fibrous roots. 



Fig. 5. Fusiform root of radish. A spindle-shaped tap-root, 

 and therefore an axial or true root. The native yam and native parsnip 

 are examples. 



Fig. 6. Soboles or creeping stem of swamp-weed. A name applied 

 to stems which run along the ground, throwing out a succession of 

 fibres below, and stalks above the surface. Examples : — Strawberry, 

 violet, and many grasses. 



Fig. 7. 1 Tuberous or lobe root of potato. A swollen underground 

 stem, with the crown on its surface. Examples : — Native sundews, 

 grass lily, Australian Colchicum, Dahlia, some Oxalis, or Wood-sorrel, 

 and many orchids. 



Fig. 8. Scaly Bulb of lily. Bulbs are divided into three kinds, as 

 shown in figures 8, 9, and 10. The scaly bulb is a thickened root, with 

 the crown on the lower end. 



Fig. 9. Corm of Victorian Crocus. Differing from a scaly bulb 

 in having a solid stem, with a very small proportion of broad, thin 

 scales. Examples : — Native snowdrop, Ixia, European Crocus, sword 

 lily. 



Fig. 10. Tunicate Bulb of Jonquil. This form of bulb possesses 

 hollow spheres, decreasing in size towards the centre ; the outer 

 spheres being of a soft texture, and hardening as they approach the 

 middle. Examples : — Daffodil, Amaryllis, tuberose, tulip, snow-flake, 

 onion, and Hyacinth. 



Fig. 11. Rhizome or root-stock of native sheathed -rush. An irregu- 

 larly-shaped, fleshy stem, growing horizontally below or in some degree 

 above the surface. New stems spring from the upper portion, the 

 lower part becoming rotten and useless. It generally bears marks 

 of former leaves and occasional buds. Examples : — Danubian-reed, 

 butterfly-flag (Iris), and several kinds of fern. 



1 Figures 7, 8, 9, and 10 are by some botanists termed ' under- 

 ground stems.' 



B 



