PART VI. 



ANALYSIS OF THE ORDERS AND FAMILIES OF 



THE FLOWERING PLANTS OF 



PATAGONIA. 



The Flowering Plants differ from the Pteridophytes by an advanced 

 development of the microsporangia into stamens bearing pollen, and of 

 the megasporangia into ovules which become embryo-bearing seeds. They 

 contain two chief classes, the antique one called the Gymnospermia, hav- 

 ing pteridophytic affinities ; and the modern class, known as the Angio- 

 spermia, because of their seed being in true seed-vessels, with stigmas. 



The superclass of Angiosperms is itself composed of two classes the 

 Monoctyledones, and the Dicotyledones, the latter being the larger. And 

 each of these classes contains a considerable number of Plant families ; of 

 which according to Engler and Prantl, there are 280, namely 4 families 

 in the Gymnosperms, 43 families in the Monocotyledones, and 233 families 

 in the Dicotyledones. When a family is named from one of its leading 

 genera, which is usually the case, its name has -acece for termination ; as 

 from Lilium, the family Liliacece. Alliances of natural families are known 

 by the terminal -ales as Liliales. These are becoming known as Orders. 



It is found convenient to break up the large Class of Dicotyledones 

 into a few subclasses, each of them containing many orders and families. 

 The character of the perianth, whether absent or, if present, whether its 

 petals are distinct from each other or coalesce, and whether the perianth 

 is superior, or inferior, or perigynous, relatively to the inner organs of the 

 flower, are of chief importance here. But we may expect exceptional 

 cases, which render the classification necessarily artificial. It must also 

 be remembered that a natural system is not serial ; that even if we knew 

 all the interrelations of the families it should be necessary to arrange them 

 not in line but in space, like the ramifications of a tree. In the system 

 here adopted we begin a large group with the simplest forms among its 



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