408 Transactions. 



Rah. — This interesting plant occurs only on Antipodes 

 Island, and only in a certain part of that island. It is the 

 dominant member of an association found on " the bare ground 

 manured by the giant petrel (Ossifraga gigantea) , ' (p. 293). 

 In this respect it resembles the endemic Cotula featherstonii of 

 Chatham Island, which is found growing near the holes of the 

 mutton-birds. With this Senecio are associated " very thick 

 masses of Acama frequently mixed with Pteris incisa." With 

 regard to this fact that we have an endemic species arising in 

 two instances under similar conditions, Dr. Cockayne expresses 

 himself thus : "I do not see why rich heavily manured soil 

 should not be just as much a factor in determining the life-form 

 of a plant as illumination, moisture in the air, wind, or any other 

 ecological factor ; and to find two plants each of distinctly luxuri- 

 ant growth growing under very similar conditions is suggestive, 

 to say the least " (p. 293). 



Dr. Cockayne brought a plant from the islands and it was 

 planted on the rockery, but it has since died, and shows no 

 signs of sprouting again. There were only two or three green 

 leaves left on the plant when I examined the rockery at the 

 beginning of this year, and I was advised to examine them at 

 once if I wished to do so at all, and therefore took the earliest 

 opportunity of doing so before the plant died. 



Anatomy (fig. 18). — This section includes the midrib, causing 

 a marked prominence on the under side of the leaf and marked 

 by a deep depression on the upper side. There is a very thin 

 cuticle, if any at all, but the epidermal cells are provided with 

 greatly thickened cell- walls. Those of the upper epidermis (ep.) 

 are much larger than those of the lower. In the young leaf 

 which was examined the woolly tomentum (h.h.) was present on 

 the lower surface and protected the stomata (st.), which occur 

 only on this surface in the areas between the veins. The guard- 

 cells contain several large chlorophyll corpuscles. The chloren- 

 chyma is arranged as in any typical dorsi-ventral leaf. The 

 palisade tissue (pal.) is two layers in thickness, composed of 

 typical palisade cells with chlorophyll corpuscles arranged on 

 the side walls. This passes into the open spongy tissue (sp.) 

 which comprises the greater thickness of the leaf. A mass of 

 thin-walled rounded parenchyma cells occupies the keel of the 

 leaf, the larger cells near the main vascular bundle (v.b.) and 

 smaller cells towards the epidermis, which here consists of a 

 single layer of small thick- walled cells. In the phloem (ph.) 

 of the bundle figured is a canal (c.) lined with epithelium (&.). 

 The xylem (xy.) consists of rather large vessels arranged in 

 chains. 



