310 Transactions. — Botany. 



paper shows that the exception referred to is an unnamed 

 species of Laminaria from Vancouver Island. As OHver 

 mentions that he has found " trumpet-hyphae " in Lessonia 

 {lac. cit.), but does not state in what species, it seems probable 

 that in the species he examined callus is wanting, as he is not 

 likely to have overlooked it. He also refers to Grabendorfer 

 as having figured " trumpet-hypha3 " for L. ovata in a paper 

 in the Bot. Ztg., 1885, entitled " Beitrage zur Keutniss d. 

 Tange." I regret that I have not access to this magazine, as 

 it would have been interesting to compare the structure of the 

 stem in the two species ovata and variegata ; and Grabeu- 

 dorfer's paper, no doubt, would have assisted me much in the 

 preparation of this. 



EXPLANATION OF PLATES XXXIX., XL. 

 Plate XXXIX. 



Fig. 1. Young specimen of Lessonia variegata, showing the immature- 

 forms of the rhizoid and fronds. (About one-sixth natural size.) 



Fig. 2. Group of stems, showing transverse sections. In two of them the 

 central tissue is divided, probably showing coalescence of two 

 separate stems. 



Plate XL. 



Fig. 1. Fragment of mature specimen of Lessonia variegata. (About one- 

 seventh natural size.) 



Fig. 2. A perfect frond, showing acuminate apex, and the method of 

 branch-formation by fission. A secondary fission is com- 

 mencing before the first one is completed. (About one-quarter 

 natural size.) 



Fig. 3. Transverse section from the epidermis to the centre of a frond, 

 showing intercellular spaces, (x 200 diam.) 



Art. XXXII. — On the Occurrence of Xanthium strumarium, 



Linn., in Neiv Zealand. 



By T. W. Kirk, F.L.S. 



[Read before the Wellington Philosophical Society, 26th July, 1S93.'] 



I HAVE on previous occasions drawn the attention of members 

 of this Society, and also of the Field Naturalists' Club, to some 

 very undesirable importations — notably, centipedes and milli- 

 pedes arriving in bananas, the English mole-cricket, and 

 others. 



The most recent of these arrivals is a plant which, if accli- 

 matised, will probably prove harmful to both the cattle- and 

 sheep-farmer. 



