APPENDIX 603 



NOTE 79 (page 395) 

 ON WILLOW-LEAVED RIVER-SIDE PLANTS 



A number of observers, beginning with Humboldt, in his Ansichten der 

 Nature, and including Seemann, L. H. Grindon, Ridley, Beccari, and others, 

 have referred to what is called " stenophyllism " in plants. These willow- 

 leaved river-side plants are found all over the globe, such plants usually 

 growing close to the water's edge in situations where they are liable 

 to be more or less submerged when the river is in flood. Seemann, Beccari, 

 and Ridley mention more than two dozen genera belonging to a great 

 variety of orders, and including Acalypha, Antidesma, Calophyllum, 

 Eulalia, Eugenia, Fagraea, Ficus, Garcinia, Ixora, Lindenia, Melastoma, 

 Podocarpus, Psychotria, &c., all tropical, and represented either in Fiji, 

 Borneo, or in the Malay Peninsula ; whilst my readers will recall amongst 

 temperate floras river-side plants of the genera Epilobium, Lythrum, Salix, 

 &c., possessing the same form of leaf and the same station. The genus 

 Eugenia comes under this category in Fiji, Borneo, and the Malay 

 Peninsula, with reference to one or more of the species. In Fiji, species 

 belonging to the genera Lindenia and Dolicholobium especially attracted 

 my attention in this respect. It is noteworthy that several of the Bornean 

 plants and some of the Fijian plants here concerned are endemic. Just 

 as I have remarked in the question of the buoyancy of seeds and fruits, 

 that not all water-side plants have buoyant seeds or fruits, but that nearly 

 all plants thus endowed are found at the water-side, so we may say of the 

 willow-leaved plants, that not all river-side plants have the willow-form of 

 leaf, but that plants thus characterised gather at the river-side. Beccar 

 and Ridley regard this willow-form of leaf as the result of adaptation. 

 Seemann remarks that we have here the old question whether the webbed 

 feet of a duck are the cause or the effect of the bird's swimming ; and I 

 take the same position. (See Seemann's Flora Vitiensis ; Ridley in 

 Trans. Linn. Soc. Bot., vol. iii. 1888-94; and Beccari's Nelle Foreste di 

 Borneo, 1902, or the English edition of 1904.) 



NOTE 80 (pages 255, 504) 



MR. PERKINS ON THE HAWAIIAN LOBELIACE^E (Fauna hawaiiensis, 



vol. I.) 



My view, that the early Hawaiian Lobeliacese acquired the monstrous 

 form of their flowers in the humid forests of a later age, is supported by the 

 observations of Mr. Perkins on the connection between the highly- 

 specialised nectar-eating Drepanids of Hawaii and the highly-specialised 

 flowers of the Tree-Lobelias, a subject further discussed in Chapter XXXIII. 

 This naturalist ascertained, in the case of one of the trees, that fertilisation 

 could only be effected by these birds. So close is the biological connection 



