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 appUcations 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 veiy fond of the seeds of the plantain. 



Aggregate flowers. 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 flowers 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, (Cephalanthus,) 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-clefl 

 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 (DipsacK<)) 

 belongs to the aggregate flowers; its inflorescence is in heads of the 

 form of a cone. The receptacle is furnished with narrow, stiflT 

 leaves in the wild Teasel, {sylvestris ;) in the cultivated species, {ful- 

 lonum,) these bristly leaves are hooked, and are used by clothiers to 

 raise a nap or furze on woollen cloth. The Cormis, 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 florida, 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 florida, 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. 126, is the Cissus,-\ or false grape; its calyx is very 



* From occidens, 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 Peiitandria. 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, 



