CLASSIFICATION. 



TABLE OF CLASSES. " 



Class I.— DICOTYLEDONS. 



Stem, when perennial, consisting of a pith in the centre, ot 

 one or more concentric circles containing fibrous tissue, and of 

 bark on the outside. Seeds with two cotyledons, the young 

 stem in germination proceeding from between the two lobes of 

 the embryo, or from the notch in its summit. 



These characters are all that can be said to bj2 constant to 

 separate Dicotyledons from Monocotyledons, They are, however, 

 in most cases very difficult to observe, and yet the distinction is 

 essential, for these two great classes have each their peculiar aspect, 

 which, after a very little habit, the botanist will in most cases 

 recogn'se at a glance. The nerves of the leaves are branched 

 and netted, and the parts of the flower are usually in fours or 

 fives {see the " Handbook,'' p. i). Families i.-lxxiv. 



Class II.— MONOCOTYLEDONS. 



Stem not distinguishable into pith, wood, and bark, but con- 

 sisting of bundles of fibres, irregularly imbedded in cellular tissue. 

 Seeds with one cotyledon, the embryo imdivided, the young 

 stem being developed from a sheath-like cavity on one side. 



Besides these positive characters, ATonocotylcdons may be 

 generally known by their simple, entire, alternate or radical 

 leaves, with siniple parallel veins, the base usually encircling or 

 sheathing the stem or the base of the next leaf; and the parts of 

 the flower are most frequently in threes, the calyx and corolla, 

 when present, being generally similar in appearance, forming a 

 single perianth of 6 parts (see the " Handbook," p. 418). 



Families Ixxv.-lxxxix, 



Class III.— VASCULAR CRYPTOGAMS. 



No real flowers, that is, neither stamens, nor pistils, nor true 

 seeds, the fructification consisting of minute. granules, called 

 Spores, variously enclosed in Spore-cases, or embedded within 

 the substance of the plant. The few British Cryptogains which 

 are included in the present volume have all of them roots, and 

 stems or rootstocks as in flowering plants, and in a few the 

 leaves are somewhat similar {see the " Handbook," p. 547)- 



Families xc.-xciv. 



