144 
CLASS TETRANDRIA. 
the spring, in grassy fields and meadows ; the colour varies from 
sky-blue (which gives its specific name ccerulea) to a pure white. It 
has a small calyx, with four divisions, and a monopetalous corolla 
of four divisions, which gives it the appearance of a cruciform plant. 
The common Plantain, (Plantago, — see Fig. 126, a,) is found 
here ; it is a plant by no means useless, although it exhibits nothing 
interesting to gratify the sight. The leaves are sometimes used in 
external applications for medicinal purposes ; they are also, when 
young and tender, boiled and used for greens in some parts of the 
United States. The flowers of the plantain grow on a spike; they 
are very small, but each one has a calyx and corolla ; these are four- 
parted ; the filaments are long, and the pericarp is ovate, with two 
cells. Canary birds are very fond of the seeds of the plantain. 
Aggregate Jiowers. We find in this class what Linnaeus called the 
aggregate flowers, such as have many flowers on the same recepta- 
cle ; they have a general resemblance to the compound flovv^ers in 
the class Syngenesia, but differ from them in having but four sta- 
mens, with anthers separate, while the Syngenesious plants have 
five united anthers. The aggregate flowers are not often yellow, 
like many of the compound flowers, but are usually either blue, 
white, red, or purple. The Button-bush, (Cep/ialanthus,) of about 
five feet in height, affords a good example of this natural order. The 
inflorescence is white, appearing in heads of a globular form, each 
consisting of many perfect little florets ; each head has its own 4-cleft 
calyx, but there is no general calyx, or involucrum, for the whole. 
Only one species of this genus, the occidentalism'^ is known, and this 
is entirely confined to North America. The Teasel (Dipsacus) 
belongs to the aggregate flowers ; its inflorescence is in heads of the 
form of a cone. The receptacle is furnished with narrow, stiff 
leaves in the wild Teasel, (sylvestris ;) in the cultivated species, (ful- 
lonimj) these bristly leaves are hooked, and are used by clothiers to 
raise a nap or furze on woollen cloth. The Cornus, so called from 
the Latin cornu, a horn, on account of the hardness of the wood, is 
a genus composed mostly of shrub -like plants, with flowers growing 
in flat clusters, or cymes, like the elder. The Jlorida, a species of 
Cornus, often called box-wood, sometimes dog-wood, is a beautiful 
ornament of our woods. It may be considered either a large shrub 
or a small tree; it grows from the height of fifteen to thirty feet. Its 
real corollas are very small, and are clustered together in the man- 
ner which is called, in botany, an aggregate. This aggregate of 
flowers is surrounded by that kind of calyx called an involucrum, 
which, in this plant, consists of four very large leaves, usually white, 
but sometimes of a pale rose-colour ; to the latter circumstance is 
owing its specific name forida, or florid. You would, no doubt, on 
the first sight of this plant, mistake the large leaves of the involu- 
crum for the petals. At Fig. 126, b, is a representation of a species 
of the cornus ; the style is about the same length as the petals ; these 
are four is number, oblong and equal. 
At c, Fig. 126j is the Cissus,-\ or false grape; its calyx is very 
♦ From ocoidens, the west, being found on the western continent. 
t Mirbel thus names the plant whose flower is here described, and places it in the 
class Tetrandria. Eaton describes it under the name of Ampelopsis, and places it in 
the class Pentandria. Although it may occasionally be found with five stamens, its 
four petals and four divisions of the calyx, seem to indicate that the fifth stamen is 
but an accidental circumstance; this seems to have been the opinion of Mirbel and 
some others. 
Plantain— Aggregate flowers— Button-bush— Teasel— Cornus—Cissus. 
