328 Transactions. 



4. MUEHLENBECKIA AUSTRALIS. 

 A. LIFE-FORM. 



This is one of the most widespread inhabitants of the forest, growing 

 both in the shade and in the bright sun at the forest-edge ; in the damp un- 

 drained area and in the neighbourhood of drains, and in the driest exposed 

 situations. In the forest-interior it is found twining round the thin trunks 

 of young trees and shrubs. Its direction of twining is not uniform, as in 

 Parsonsia, but different individuals twine some right and some left. Further, 

 a single plant may commence its growth as a sinistrorse twiner, and after 

 a few turns become displaced by a projecting branch of the support, beyond 

 which it continues its twining in a dextrorse manner. The highest position 

 of the liane is on the branches of the tallest trees, 30-40 m. from the ground ; 

 but in no case does the liane twine round their trunks. On the contrary, 

 the liane-stems usually hang freely from the supporting branches at a 

 distance of 1-5 m. from the large trunk, or perhaps quite near the latter, 

 either growing fairly erect from the root or with their stems coiling first 

 along the ground for a distance of fully 12 m. From these coiling stems 

 adventitious roots pass ofi, which sometimes grow near the surface and 

 attain a length of 1 m. The hanging stems almost invariably are greatly 

 twisted, suggesting that they commenced their growth on smaller support- 

 ing trees, which they finally strangled ; indeed, the climbing-stem frequently 

 encircles a portion of some stem which has been strangled (Plate XXV, 

 fig. 2). The condition of these decaying remains shows how intense has 

 been the " struggle " between liane and support. Both stems may be 

 greatly compressed, and the tissues of the support between the liane- 

 coils may be growing out and nearly surrounding the liane. But it is a 

 significant fact that in no place has a tree been found which indicates 

 that it has ever been tightly surrounded by one of these Muehlenheckia 

 stems. 



On the top of the supporting tree the liane-shoots branch freely, the 

 branches, interweaving and twining round each other, forming an efficient 

 platform for the display of foliage. Many shoots project beyond the support, 

 and, continuing their growth, gradually hang down. The growing apex, 

 however, is apogeotropic, and upon coming into contact with the hanging 

 portion commences to twine upward round this same shoot. 



In the more exposed portions of the forest, where the supporting trees 

 have numerous branches, the Muehlenbeckia shoots hang down in large 

 numbers, and on their lateral branches bear large masses of foliage. The 

 species is very abundant at the edge of the forest, where it is found grow- 

 ing over low shrubs. Here the liane forms large straggling masses, whose 

 slender stems do not grow so long as in the forest, but bear numerous branches 

 which, unable to grow erect in the absence of a support, interweave freely, 

 and thus form cushion-like masses. In these exposed situations the species 

 is almost deciduous. A few plants lose all their leaves ; others, which are 

 more sheltered, are semi-deciduous ; finally, in the shelter of the forest, 

 the plants are evergreen. 



A most noticeable feature oj the species is the production of adventitious 

 shoots. These arise in autumn from almost any part of the adult, being found 

 on the leafy stems at the top of the support, and on the adult stems trailing 

 along the forest-floor. Although at most 0-7 cm. in diameter, they can grow 

 erect for 1-5 m., after which they bend over until they touch the ground ; 

 but if the terminal shoot be injured a lateral shoot may arise from any 



