Cockayne. — On Aerial Rhizomes. , 405 



JuncacecB. 



Luzula campestris, D. C, var. australasica, Buchen. (?) 



Orchidacece. 

 Thelyniitra uniflora, Hook. f. 



* Aizoacece. 



Mesembrianthemum australe, Sol. 



Crcissulacece. 

 Crassula moscliata, Forst. f. 



Araliacece. 

 Stilbocarpa Lyallii, J. B. Armstg. 



Umhelliferce. 

 Apium prostratum, Lab. 

 Aciphylla intermedia {Hook. /.). 



Boraginncece. 

 Myosotis capitata, Hook. /., var. albiflora, J. B. Armstg. 



ScwphularinacecB. 

 Veronica elliptica, Forst. f. 



Compositce. 

 Olearia Colensoi, Hook. f. 

 Senecio Stewartife, J. B. Armstg. 



„ rotundifolius {Forst. /.), Hook. f. 



Art, XXXIX. — Note, on Aerial Rhizomes in Cordyline australis. 



By L. Cockayne, Ph.D. 



\Read before the Philosophical Institute of Canterhury, ith November, 1908.] 



As is well known, the common New Zealand cabbage-tree {Cordyline aus- 

 tralis) sends deep down into the ground a continuation of its ordinary up- 

 right-growing trunk, from which it differs in its positive geotropism, pos- 

 session of roots, and rudimentary scale-like leaves. This rhizome functions 

 not merely as an anchor for the plant, which is kept in place by the spread- 

 ing horizontal or semi-horizontal roots ; but it serves as a storage-organ 

 for food, on the relative amount of which depends, doubtless, the blooming 

 of the tree. If the trunk be cut oft' below the level of the ground, new aerial 

 negatively geotropic shoots will be produced, and, vice versa, if the cut-oft" 

 aerial portion can be induced to grow, a new positively geotropic shoot 

 (rhizome) will be produced at its base. Frequently the trunk will put forth 

 from any part ordinary leafy shoots, and occasionally near its base small 

 positively geotropic rhizomes will be developed. 



Some years ago the Hon. E. C. J. Stevens, M.L.C., called my attention 

 to a fine specimen of Cordyline australis growing in the grounds of the Christ- 

 church Club, which had a profusion of aerial rhizomes issuing from its trunk, 

 not from near the base, but at a considerable distance from the ground. 



