145 



known Indian trees, from the stems of which sago or starch 

 is obtained. 



128. Coniferae. These include Conifer. 



much branched woody plants with undivided, usually acicuiar, 

 leaves. The wood does not contain true vessels but often 

 possesses resin ducts. The flowers have no perianth and are 

 usually cones, i.e. shoots carrying scale-like sporophylls, the 

 latter bearing the ovules and pollen-sacs. In this group 

 are included very many important forest-trees such as the 

 Pines, Firs, Spruces, Cedars, Larches, Cypresses, Junipers 

 and others. 



129. Gnetaceae. The leaves are un- Gnetaceae. 

 divided, often broad and usually opposite. The stem and 

 branches are jointed at the nodes. The flowers are not cones, 



they have a rudimentary perianth and are usually arranged in 

 slender spikes. The wood contains true vessels. 



Ephedra Gerardiana is a small, apparently leafless, shrub, 

 fairly common in Jaunsar. 



Several species of Gnetum occur in India. They are 

 generally climbers with broad, well developed, opposite leaves. 



130. Angiosperms. The macrospo- Angiosper 

 rophylls, or carpels, form closed cavities called ovaries, within 

 which are contained the ovules. The pollen is received not 



on the micropyle of the ovule, but on a specialised portion of 

 the carpel called the stigma. The oophyte developed by the 

 macrospore is small and consists of only a few cells which are 

 usually without cell-walls, one of these naked cells being 

 the oosphere. After fertilisation has taken place, 

 however, the cavity of the spore becomes filled with 

 tissue which has also been called endosperm, but which is 

 clearly not the same, morphologically, as the endosperm of 

 Gymnosperms which is developed before fertilisation. The 

 flowers are, typically, hermaphrodite with a perianth. The 

 Angiosperms are sub-divided into two groups : 



Monocotyledons. 



Dicotyledons. 



131. Monocotyledons. The embryo Monocoty- 



has typically one cotyledon which usually remains below the ledons - 

 ground. These plants are usually herbaceous and are 

 rarely shrubs (species of Smilax for example), or trees 

 (Palms and Bamboos). The flowers have their parts typically 

 in whorls of three. The leaves usually have parallel 

 venation. Species of Smilax and Dioscorea are the most 

 important exceptions with reticulate venation. The leaves 



