106 Transaction s . 



Art. XVI. — Helichrysum dimorphum Cockayne — a Hybrid? 



By A. Wall, M.A., Professor of English, Canterbury College. 



[Read before the Canterbury Philosophical Institute, 1st October, 1919 ; received by Editor, 

 3rd October, 1919 ; issued separately, 10th J\ine, 1920.] 



Helichrysum dimorphum was discovered by Cockayne near the confluence 

 of the Poulter and Waimakariri Rivers and described by him in 1915. 

 Another plant was found by the same authority at Pufier's Creek, which 

 runs into the Broken River not far from its junction with the Waimakariri. 

 The two localities are about ten miles apart. The species has not been 

 found again. 



I visited the Puffer's Creek locality in February, 1919, and took speci- 

 mens. The object of this paper is to suggest that Helichrysum dimorphum 

 is a hybrid between H. filicaule and H. depressum, just as H. Purdiei seems 

 to be certainly a cross between H. glomeratum and H. bellidioides. 



Helichrysum dimorphum is a strong climber. The plant has a lusty, 

 thriving appearance, and the branches grow in very great profusion and are 

 most thickly massed together. Climbing upon a plant of Coprosm.a pro- 

 pinqua it shows leafless branches in the open, and leafy branches wherever 

 it is at all shaded. The flowers, which are not fully open in my specimens, 

 are borne upon the leafless branches. H. depressum occurs close to it in 

 the bed of the creek, and H. filicaule is, as usual in such localities, abundant 

 all round it. The plant grows about 8 ft. or 10 ft. above the bed of the 

 creek. 



Helichrysum filicaule shows a distinctly scandent or semi-scandent habit 

 whenever it grows among tall plants, such as Discaria or Leptospermum. 

 I have collected specimens over 2 ft. in length at Akaroa and elsewhere, 

 one of these being found in the immediate neighbourhood of the Pufier's 

 Creek plant when I was unsuccessfully searching for it in 1917. H. depressum, 

 on the other hand, has been observed growing in actual contact with plants 

 of Discaria without showing any tendency to climb. 



My suggestion is that H. dimorphum is a cross between the two, 

 deriving its scandent habit from H. filicaule, and its strength and solidity 

 of form, which enable it to become a true climber, from - H. depressum. 

 As regards the inflorescence, H. dimorphum appears to be more closely 

 related to H. depressum than to H. filicaule. The flowers in my specimens 

 are just sufficiently advanced to make this quite clear. The resemblance 

 to the flower and involucre of H. depressum is very close indeed. The 

 flower is sessile at the tips of the branches, as in H. depressum, not terminal 

 on a long filiform peduncle, as in H. fidicaule ; and the involucral bracts in 

 their number and arrangement are exactly like those of H. depressum, 

 the involucre being rather cylindrical than hemispherical. 



In support of the^ theory I should adduce the following considerations : — 



(1.) In both its localities both H. filicaule and H. depressum are present 

 at no great distance. In the Poulter locality the plant grows on the top 

 of a high terrace (perhaps 60 ft. to 80 ft.) above the river, in whose bed 

 H. depressum is abundant, while H. filicaule is present everywhere about it. 



