116 



OEDEE LXni. DIPSACE.E. OEDEE LXIV. COMPOSITE. 



OBDER LXIII. Dipsaceae. 



Herbs. Leaves opposite, or verticillate, sessile. Stipules 

 none. Flowers in dense involucrate heads. Calyx-tube adherent 

 to the ovary. Limb somewhat campanulate, entire, or toothed, 

 sometimes taking the form of a pappus. Corolla tubular, with a 

 4 5-lobed, slightly irregular limb. Stamens 4, distinct, rarely 

 united in pairs, often unequal, inserted on the corolla. Ovary 1- 

 celled, containing 1 ovule. Fruit a bony achenium. 



A small order of plants, native only of the old world. Fuller's Teasel (Dip- 

 tacus fullonum), and another species, D. sylvestris, which is naturalized in 

 rarious districts of the United States, are examples. 



GROUP II. 

 ORDER LXIV. Composite. 



Herbs, or shrubs. Leaves alternate, or opposite, without 

 stipules. Flowers arranged in dense heads, on a common recep- 

 tacle, and surrounded by an involucre of bracts; the separate 

 flowers often with chaffy bracteoles somewhat like a calyx. 

 Calyx-tube adherent to the ovary ; limb obsolete, or present, and 



Fig. 17. 



assuming the various forms of bristles, hairs, scales, and is termed 

 pappus. Corolla ligulate, or tubular, often 5-cleft, and rarely 

 wanting. Stamens 6, their anthers united in a tube. Ovary 1- 

 celled, 1-ovuled. Style 2-cleft. Fruit a dry indehiscent ache- 

 nium crowned with the pappus. This order is divided into 3 

 suborder, Tubuliflorae, Liguliflorae, and Labiatiflorse, only the 2 

 first of which are represented in the Northern States. In Tubu- 

 liflorse either all the flowers, or the central flowers, are tubular. 

 This structure is exemplified in the Thistle, one species of which 

 (Cirsium lanceolaturri), is seen in fig. 17, where the flowers are all 

 tubular. In the same 1 figure is shown one of the separate flowers, 

 or florets, with its pappus surrounding the tubular 5-cleft corolla, 

 that incloses the tube of 5 united anthers, through Which projects 

 the bifid style. In fig. 18 (Aster patens), we have an illustration 

 of the form in which only the central florets are tubular, those of 

 the ray being ligulate, or strap-shaped. The two kinds of florets in 



this species are seen in the same figure. In the Ambrosia artemisiap- 

 folia, fig. 19, we have an example of this sub-order in a reduced 

 form, with moncecious flowers destitute of corollas. In the second 

 suborder, Liguliflorse, the flowers are all ligulate, as in the Dan- 

 delion, fig. 20. 



Fig. 18. 



This is a vast order, much larger than any other in the Natural System, and 

 comprehending about 9000 species. But their Importance hardly corresponds 

 with their abundance. The whole order is pervaded by a bitter astringent 

 principle, which is sometimes tonic, as in the Boneset (Eupatoriwn perfolia- 

 twri), and the Camomile. In others it is aromatic, as in Artemisia ( Worm- 

 wood), or even acrid, as in Maruta (May-weed). The Boneset also has emetic 



Fig. 19. 



properties. The seeds of the Sun-flower (ITelianthus), yield a bland oil ; and 

 the tubers of the Jerusalem Artichoke (// tuberosu*), which are represented 

 in flg. 2, Plate X, are sometimes eaten as food. The Liguliflorse all have a 

 milky juice, containing a narcotic principle, which, especially in the Lettuce, 

 has been used for opium. The order also includes many highly ornamental, 

 but not delicately beautiful plants, such as the Aster, Dahlia, Zinnia, and 

 Calendula. 



