PART I. | HISTORICAL INTRODUCTION. 15 
or the filaments themselves, being long and pendulous; in some 
cases the stamens are explosive, and project all the pollen into the 
air. The following five varieties may be distinguished among 
anemophilous Angiosperms :— 
(a) Forms with catkins, in which the axis of the male 
inflorescence is movable. Ex. Corylus, Betula. 
(b) Forms with pendulous flowers. Ex. Negundo fraxinifolium, 
Rumen. 
(c) Forms with long stamens. This is the most common variety, 
including almost all Graminew, Cyperacee, Juncacew, Cannabis, 
Humulus, Empetrum, Mereurialis, Ricinus, Plantago, Littorella, 
Callitriche, Myriophyllum, Hippuris, the anemophilous species of 
Thalictrum, &e. 
(d) Explosive forms. Ex. Urtica, Parietaria, Morus. 
(¢) Forms with immovable flowers. Ex. many Palms, Potamo- 
geton, Triglochin, Sparganium, Typha. 
C. Plants Fertilised by Animals. 
These usually possess bright colours or perfumes, and supply 
food to their fertilisers. The following classification has been 
supplied to me by Delpino, by letter :— 
I. ORNITHOPHILZ.—These plants are adapted for fertilisation 
by birds, which come in search either of honey or of small insects 
(Trochilide, Nectarinia, etc.). They present several different types. 
What is known concerning them is founded chiefly on the reports 
of travellers who were ignorant: of the principles that should guide 
their investigation. Many of them possess large brilliantly-coloured 
flowers, very frequently scarlet, pouched in form, upright in position, 
and secreting great abundance of honey. 
II. ENtoMopHILA.—Plants whose flowers are adapted for 
fertilisation by insects. To this group belong all our native flowers 
which possess perfume or bright colours. 
III. MALacopHiLt#.—Plants whose flowers are adapted for 
fertilisation by snails. (These have as yet been observed by 
Delpino only.) The flowers are crowded so closely together, that 
the snails in creeping over them must come in contact both with 
pollen and stigmas. The plants are protected from the ravages of 
their voracious guests, either by secreting an acrid fluid which kills 
the snails (Alvcasia odora), or by metamorphosis of the perianth 
into a thick fleshy tissue, with whose destruction the snails are 
content (Rhodea japonica). 
