NATURAL ORDERS. 



ARRANGEMENT OF THE NATURAL ORDERS IN 

 THE PRESENT WORK. 



The following recapitulation of the Natural Orders represented 

 in the British Isles is merely intended as a table of contents, 

 showing the order in which the families follow each other in the 

 present work ; at the same time attention is called to one or two 

 of the most striking, the most important, or the easiest observed 

 features of each one. These characters are, however, general, 

 not always without exception, and sometimes specially applicable 

 to British genera only. 



Class I.— DICOTYLEDONS. 



In the germination of the seed .the plumula arises between two 

 (rarely more) lobes or cotyledons of the embryo, or from a terminal 

 notch. The vascular tissue of the stem forms a ring or rings 

 between the bark and pith. The nerves of the leaf are branched 

 and netted (see also Arum, Tamils, z.wA Paris in Monocotyledons). 

 The parts of the flower are usually in fours or fives. 



Sub-class 1. Thalamiflorae. — Petals distinct from the calyx, 

 and from each other, seldom wanting. Stamens usually hypogynous, 

 or nearly so. Exceptions. — The calyx or corolla is absent in some 

 Kanunculacece, Cmci/erce, Violacece, Caryophyllacece. The petals 

 cohere more or less in some Fmnariacece, Polygalacece, Poriulacece, 

 Tamariscinece, Malvacea. The stamens are epigynous or peri- 

 gynous in Nymphaacea and some Caryophyllacea. 



* Ovary apocarpous. 



I. RanunculacEjE (figs. 1-32). Petals definite. Stamens 

 indefinite. 



II. BerberidE/E (fig. 33). Perianth and stamens in twos or 

 threes, or their multiples. Anthers opening by recurved valves. 



III. Nymph^ACE^ (figs. 34-5). Aquatic plants with indefinite 

 petals and stamens, the inner petals passing gradually into the outer 

 stamens. 



