United States or Moldova ? Vote for the TOP Country of the Week !
The petioles, when coming into contact with a stick, take either a complete or half a turn round it, and ultimately increase much in thickness. They do not possess the power of spontaneously revolving. Lophospermum scandens, var. purpureum. Some long, moderately thin internodes made four revolutions at an average rate of 3 hrs. 15 m.
Hence, if the leaves on some of the branches of the Lophospermum were to abort, these branches would be converted into true tendrils.
The young internodes of the Lophospermum as well as the petioles are sensitive to a touch, and by their combined movement seize an object. The flower-peduncles of the Maurandia semperflorens revolve spontaneously and are sensitive to a touch, yet are not used for climbing.
Nevertheless I do not wish to assert that they are never irritable; for the growing axis of the leaf-climbing, but not spirally twining, Lophospermum scandens is, certainly irritable; but this case gives me confidence that ordinary twiners do not possess any such quality, for directly after putting a stick to the Lophopermum, I saw that it behaved differently from a true twiner or any other leaf-climber.
This freely growing species climbs exactly like the last, by the aid of its sensitive petioles. A young internode made two circles, each in 1 hr. 46 mm.; so that it moved almost twice as rapidly as the last species. The internodes are not in the least sensitive to a touch or pressure. I mention this because they are sensitive in a closely allied genus, namely, Lophospermum.
According to Mohl and others, some tendrils consist of modified branches: I have not observed any such cases, and know nothing of their transitional states, but these have been fully described by Fritz Muller. The genus Lophospermum also shows us how such a transition is possible; for its branches spontaneously revolve and are sensitive to contact.
Plants which climb by the aid of spontaneously revolving and sensitive petioles Clematis Tropaeolum Maurandia, flower-peduncles moving spontaneously and sensitive to a touch Rhodochiton Lophospermum internodes sensitive Solanum, thickening of the clasped petioles Fumaria Adlumia Plants which climb by the aid of their produced midribs Gloriosa Flagellaria Nepenthes Summary on leaf-climbers.
Word Of The Day