Chap. II. GLOKIOSA. 79 



The hook when first formed, before the leaf has 

 bent downwards, is but little sensitive. If it catches 

 hold of nothing, it remains open and sensitive for 

 a long time ; ultimately the extremity spontaneously 

 and slowly curls inwards, and makes a button-like, 

 flat, spiral coil at the end of the leaf. One leaf 

 was watched, and the hook remained open for thirty- 

 three days ; but during the last week the tip had 

 curled so much inwards that only a very thin twig 

 could have been inserted within it. As soon as the 

 tip has curled so much inwards that the hook is con- 

 verted into a ring, its sensibility is lost ; but as long as 

 it remains open some sensibility is retained. 



Whilst the plant was only about six inches in 

 height, the leaves, four or five in number, were 

 broader than those subsequently produced ; their soft 

 and but little - attenuated tips were not sensitive, 

 and did not form hooks ; nor did the stem then revolve. 

 At this early period of growth, the plant can support 

 itself; its climbing powers are not required, and 

 consequently are not developed. So again, the leaves 

 on the summit of a full-grown flowering plant, which 

 would not require to climb any higher, were not 'sensi- 

 tive and could not clasp a stick. We thus see how 

 perfect is the economy of nature. 



CommelynacezE. Flagellaria Indica. From dried 

 specimens it is manifest that this plant climbs exactly 

 like the Gloriosa. A young plant 12 inches in height, 

 and bearing fifteen leaves, had not a single leaf as yet 

 produced into a hook or tendril-like filament ; nor did 



