258 DESCRIPTIVE CATALOGUE 



Class ANGIOSPERM-E. 



The largest and most important class of plants, which have 

 their reproductive organs enclosed and surrounded by very 

 specialised scales, the whole forming a flower, which may be 

 uni-sexual or bi-sexual, simple or complex, small and incon- 

 spicuous, or large and highly coloured, but in which the seeds 

 are always enclosed by the carpels. The vegetative structure 

 shows every range of variation from woody trees to minute and 

 simplified herbs. 



Sub-class MONOCOTYLEDONS. 



The embryo has only one cotyledon, often peculiarly modi- 

 fied and specialised; and the leaves have generally parallel 

 veins. Normal cambium and, consequently, woody trunks are 

 almost universally absent. 



The only specimen in the Lower Greensand deposits which 

 even doubtfully may be regarded as a Monocotyledon is an 

 imperfect cast, presumably of a leaf, in the Maidstone Museum. 

 The specimen measures about 24x18 cm. across, and looks 

 like the segments of a palmate leaf penetrating the coarse sand- 

 stone matrix. Its nature, however, is very doubtful. 



The other specimens which have been described as Mono- 

 cotyledons have all been disposed of in other sections of the 

 plant kingdom by later and more critical work. The principal 

 of these is the famous " Dragon -Tree," for so long placed in 

 Dracaena, a curious genus of living Monocotyledons. Its gymno- 

 spermic nature has already been demonstrated (see p. 163). 



Sub-class DICOTYLEDONS. 



The embryo has two cotyledons, and the foliage leaves have 

 generally reticulate veins. Primary bundles are in one ring, 

 normal cambium is often present, giving rise to woody trunks. 



Dicotyledons largely preponderate in the existing flora, and 

 in the lists of Tertiary and Upper Cretaceous floras, and very many 



