74 ELEMENTARY BOTANY 
or dissimilarities were neglected. Thus, plants with a single 
stamen were called Monandria; plants with two, Diandria ; 
with three, Triandria; and so on. A single character of 
this kind is not a satisfactory basis of classification. In the 
Natural present day plants with a differing number of 
System — stamens will be grouped together if they re- 
semble each other in mode of growth, structure of andreecium 
and gynecium, and other general characteristics. The plants 
belonging to the Natural Order, Scrophulariacee, afford an 
instance of this. Mullein has five stamens, Figwort four, and 
a scale representing the fifth, Speedwell only two; but these 
plants are all grouped in the same Order on account of their 
characteristic gynecium and fruit. | 
Flowering plants are divided into two great divisions : 
1. Gymnosperms (Gk. gyimmnos = exposed ; sperma=a seed), 
in which the carpellary leaves do not unite to form an ovary ; 
the ovules are therefore exposed. (See p. 40.) 
2, Angiosperms (Gk. angos=a vessel; sperma=a seed), in 
which the carpels do unite to form an ovary, so that the 
ovules they bear are contained in a chamber. : 
Angiosperms are again subdivided into Monocotyledons and 
Dicotyledons. 
Monocotyledons, as the name implies, have one cotyledon ; 
no tap-root; their stems do not as a rule increase in thick- 
ness; their leaves are parallel-veined; the floral leaves are 
usually three in each whorl. In Dicotyledons there are two 
cotyledons, often a well-marked tap-root; the stems do, as a 
rule, increase in thickness; the leaves are generally net- 
veined ; and the floral leaves in each whorl may be two, four, 
or five, never three. 
Monocotyledons and Dicotyledons are again subdivided, 
each subdivision including several Orders, of which only a few 
can be given in this book. (See table on next page.) 
According to the Natural System of classification, plants 
which resemble each other in their chief characters are grouped 
together, particular attention being paid to the androecium 
and gyneecium, less attention to the number of floral leaves. 
