DIPSACE^ COMPOSITE. 241 



3. Houstonia. Calyx 4-parted, persistent, inserted on the corolla. 

 Stigmas 2. Capsule 2-celled, many-seeded. # 



H. CCERULEA (Bluets, Innocence). Smooth ; stem slender, dichoto- 

 mous ; radical leaves spatulate ; peduncles long, filiform, i-2-flowered ; corolla 

 pale blue, fading to white, with a yellow base, somewhat salver-form. Little 

 plant, z'-S' high, in moist grounds. April-September. 



4. Cephalanthus. Calyx-limb 4-toothed. Corolla tubular, slen- 

 der, 4-toothed. Stamens 4. Style filiform, much exserted. Stigma 

 capitate. % 



C. OCCIDENTALIS (Button-busK). Leaves oval, entire, smooth, acute, 

 petiolate ; flowers in large, globose heads, white. Common in wet grounds. 

 July. 



Order XLIV. DIPSACE^E. 



Herbs. Leaves opposite, or verticillate, sessile. Stipules none. 

 Flowers in dense involucrate heads. Calyx-tube adherent to the 

 ovary. Limb somewhat campanulate, 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 I -celled, containing I ovule. Fruit 

 a bony achenium. 



Dipsacus. Flowers in heads. Involucre many-leaved. Calyx- 

 tube adhering to the ovary. Corolla tubular, 4-cleft. Stamens 4. 

 Fruit i-seeded, crowned with the calyx. %. 



D. SYLVESTRIS (Teazel}. Prickly ; leaves lanceolate-oblong, opposite ; 

 heads cylindrical ; bent inward ; bracts terminating in a long, straight awn ; 

 flowers blue. A prickly plant, 2-4 feet high. July. 



Order XLV. 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 assum- 

 ing the various forms of bristles, hairs, scales, and is termed pap- 

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

 Stamens 5, their anthers united in a tube. Ovary i -celled, i- 

 ovuled. Style 2-cleft, Fruit a dry, indehiscent achenium crowned 

 with the pappus. 



