1 8 Flowers a7id their Pedie'rees. 



into another, it does not generally happen that the 

 parent form dies out altogether : on the contrary, it 

 usually lingers on somewhere, in some obscure and 

 unnoticed corner, till science at last comes upon it 

 unawares, and fits it into its proper place in the scale 

 of development. We have still several fish in the 

 very act of changing into amphibians left in a few 

 muddy tropical streams ; and several oviparous 

 creatures in the very act of changing into mammals 

 left in the isolated continent of Australia ; and so 

 we have also many low, primitive, or simple forms of 

 plants and animals left in many stray situations in 

 every country. Amongst them are some of these 

 earliest ancestral flowers. On almost every wayside 

 pond you will find all the year round a green film of 

 slimy duckweed. This duckweed is, as it were, the 

 Platonic idea of a flowering plant — the generic type 

 common to them all reduced to its simplest elements. 

 It has no roots, no stem, no branches, no visible 

 blossom, no apparent seed ; it consists merely of soli- 

 tary, roundish, floating leaves, budding out at the 

 edge into other leaves, and so spreading till it covers 

 the whole pond. But if you look closely into the 

 slimy mass in summer time, you may be lucky 

 enough to catch the weed in flower — though not 

 unless you have a quick eye and a good pocket-lens. 



