KowE. — On Coriaria ruscifolia. 817 



Akt. XXXVII. — Observations on the Development of the Flower 

 of Coriaria ruscifolia, Linn. 



By T. W. KowE, M.A. 



[Read before the Philosophical Institute of Canterbury, 5th August, 1886.] 



Plate XXI. 



The dubious affinity of the genus Coriaria renders its study 

 interesting. My observations on the development of the flower 

 of C. ruscifolia showed many important departures from the 

 type given by Hooker. They were made almost wholly on pre- 

 served specimens gathered at various times between September, 

 when the buds first appear, and March, when the fruit is ripen- 

 ing. The bud arises, like all flower-buds, as a little rounded 

 cellular papilla in the axil of a bracteole. It grows rapidly, and 

 the sepals very quickly begin to become distinct from the rest 

 of the flower (Plate XXI., fig. 1, s). A longitudinal section shows 

 them as a rounded protuberance on each side of a central 

 cellular mass. Seen from above they have the appearance of 

 six distinct papillae. They begin to grow up around the rest of 

 the bud, and the petals and stamens arise as little rounded 

 protuberances above the upper surface of the bud (fig. 2), 

 while the central portion remains more or less flat. This, 

 however, soon becomes rounded (fig. 8), and in some sec- 

 tions seemed to be clothed with a layer of loosish cells. The 

 sepals meanwhile grow very fast, and soon begin to close over 

 the bud, while the petals and stamens grow rapidly also (fig. 4). 

 All this "is shown in flowers gathered on the same day, 

 September 30th, and the buds though showing different stages 

 of development do not vary greatly in size, as can be seen from 

 the figures. In a bud gathered on October 3rd there is seen 

 a great advance in growth (fig. 5). The sepals completely 

 close in over the rest of the bud, the petals grow around the 

 stamens, and these nearly meet over the pistil, which now shows 

 six distinct styles. Like the sepals, the petals, stamens, and 

 styles arise as little papilla, seen from above to be distinct from 

 each other. All the four whorls of the flower have six segments 

 each, although the flower is a Dicotyledon. This renders it 

 extremely interesting. Hooker, in his account of the Coriariece, 

 mentions nothing of this peculiarity, but says that the parts of 

 the flowers of the Cvriariea are in 5's or lO's. In the C. rusci- 

 folia, however, I have found nothing but six in all four whorls 

 of the flower. I cannot account for the prevalence of this 

 number in the plant : nothing I have seen has tended to show 

 how it arises, whether by the doubling of one (or two) parts, or 

 by the suppression of two (or four) out of an original eight (or 

 ten) ; but neither of these suppositions seem at all probable. 



