20 
Principles of Classification- . 
variously and alternately subdivided, as in the common 
laurus-tinus and elder. 
Panicula or panicle, has the flowers in a loose subdi- 
vided bunch or cluster, without order. When the 
stalks are distant, it is called a spreading panicle, as in 
London-pride, saxifraga umhrosa, and in the fcommon 
cultivated oat. When the panicle is more crowded 
it, is called dense or close, and when more spreading, 
it is said to be divaricated. 
Thyrsus, a bunch, is a dense or close panicle, ap- 
proaching to an ovate form, as in the common lilac ; 
and tussilago petasites , or common: butter bur, is also- 
an example of the thyrsus. . 
Stems. — A flower stalk is said to be solitary when it 
bears one flower $ clustered, in which several stems are 
united together ; radical, when they arise from the 
root ; cauline, when they spring from the stem ; axil- 
lary, when they grow from the axillae of the leaves ; 
and lateral, or terminal, as they proceed from the side 
or extremity of the stem. 
Culrnus, Culm, or straw, is the stem peculiar to the 
grasses, rushes, and similar plants. It is either with- 
out joints, as in, the common rush ; jointed, as in most 
of the grasses ; genicnlated, or knee’d, as in a common 
species of fox- tail grass. 
Scapus , or stalk, is that stem which springs from the 
root, and supports the flower and seed, but not the 
leaves,, as in the common primrose. 
JPedunculus , is the flower-stalk which springs from 
the stem, and supports the flowers and fruit, but not 
the leaves. 
Petiolus, or petiole, is the foot-stalk of the leaf, and 
Is a term exclusively appropriated to leaves;, and it is 
