^. M. Thomson. — On the Fertilization of Floivering Plants. 255 



H. gramineum lias very bright, golden-yellow flowers, which are, how- 

 ever, destitute of smell, and also, I believe, of honey. The numerous stamens 

 do not dehisce all at once, but one after another, and they produce a great 

 quantity of pollen. H. jaiwnicum has its fully-formed flowers very similar 

 to the other species, but much smaller. It is remarkable, however, for pro- 

 ducing besides a set of flowers in which the capacity for self-fertilization is 

 so complete that they have almost become cleistogamic. There is no true 

 abortion, but only great diminution of the corolla and stamens, and the 

 flowers produce seed without having ever opened. It appears to me that we 

 have here a case of variation going on. Probably the examination of a large 

 series of specimens would show that some had acquired complete cleistogamy. 

 I think both species of Hyjjericum are self-fertilized by the withering and 

 curling-in of the petals, which thus smear the stigmas with pollen, if they 

 have not previously been crossed by insects. 



Nat. Ord. Malvace^. 



This order is represented by three genera — Plagianthus, Hoheria, and 

 Hibiscus, but only the first two occur in Otago. 



Plagianthus divaricatus is a low shrub, occurring abundantly on the 

 muddy shores at the head of Otago harbour. It is strictly dioecious, the 

 male flowers having no trace of a pistil, and the female being furnished 

 with rudimentary stamens, which produce no pollen. The former are 

 much more numerously produced, and are, therefore, more conspicuous 

 than the latter. They produce little or no honey, but to make up for their 

 small size they are extremely fragrant. 



P. betulinus is also strictly dioecious. The male flowers are produced in 

 dense panicles, which are whitish-yellow in colour, and are thus very con- 

 spicuous ; they have no trace of a pistil. The pistillate flowers are in lax 

 panicles, are much more sparingly produced, and, from then' greenish 

 colour, are rather inconspicuous. The style is surrounded at its base by 

 a ring of abortive stamens, and the stigma is a wide flattened expansion, 

 proportionally large to the rest of the flower. Both kinds of flowers are 

 very fragrant, and produce honey, the female in this latter respect being 

 better provided than the male. 



I have not had an opportunity for years of examining P. lyallii, the 

 flowers of which are very large and white. 



Hoheria jyopulnea produces great masses of pure white flowers. 

 These are quite hermaphrodite, and appear to depend for their crossing 

 almost entirely on their conspicuousness. They have neither scent nor 

 honey, nor do they appear to be at all dichogamous. 



Nat. Ord. Tiliace^. 



There are three genera of this order in New Zealand : viz., Entelea (not 

 foimd in Otago), Aristotelia and Elceocarpus. 



