-^ 



DiPSACUs. LXXIV. DIPSACEiE. 309 



1. P. Fagopyrum. Torr. & Gray. ("Valerianella radiata. Mcench.) Wild 

 Cm-n-scdad or Lamb Lettuce. — St. dicnotomous, nearly smooth ; Ivs. oblong- 



spatulate, subenlire ; /r. 3-sided, obscurely 2 — 3-toothed at the summit. — West- 

 ern N. Y. to Ohio ! Stem 8 — 18' in height. Bracts lanceolate, acute. Fruit 

 resembling that of buck-wheat (Polygonum Fagopyrum) in form, containing 

 one large seed and two empty cells. Flowers white. June. 



2. F. RADIATA. Michx. 



Liis. entire, or toothed towards the base, obtuse ; jls. white ; fr. ovoid, pu- 

 bescent, somewhat 4-angled, obscurely 1-toothed at apex ; emfty cdls not di- 

 vergent, but with a groove between them.; fertile cell flattish, broader than the 

 other 2. — Low grounds, Mich. ! Ohio ! to La. Stem 6 — 12' high, dichotomou& 

 like the other species, smooth. Leaves oblong, more or less tapering to the 

 base, 1 — 2' by '^ — 4". Fruit less than 1" long, at length nearly smooth. May. 



3. F. OLiTORiA. Vahl. Pawnee Lettuce. 



Fr. compound, oblique, at length broader than long, not toothed at apex ; 

 fertile cell larger than both the others ; empty cells united, but with a groove 

 between; Ivs. spatulate-obtuse, radical ones ]>etiolate; Jls. pale blue. — Natural- 

 ized in some portions of the U. S. Stem smooth, 8^ — 12' high, dichotomous. 

 Leaves mostly entire. Flowers in dense cymules. Fruit V diam. June. \ 



4. F. UMBiLiCATA. W. S. Sullivant. 



Fruit subglobose, inflated, apex 1-toothed, the anterior face deeply umbili- 

 cate, sterile cells several times larger than the fertile one; bracts subspatulate- 

 linear, not ciliate. — Columbus, Ohio, Sullivant! Plant smooth in all its parts, 

 1 — 2f high, many times dichotomous. Leaves oblong, obtuse, clasping, dilated 

 and coarsely dentate at base, 1 J' — 3' by 3 — 10". Flowers in numerous cymules, 

 corymbosely arranged. Fruit nearly 1" diam., with 1 rib at the back produced 

 into a tooth at apex, and a conspicuous depression in front. 



Order LXXIV. DIPSACE^.— Teaselworts. 



Herbs nr low shrubs, with whorled or opposite leaves. 



Fla. collected upon a common receptacle and surrounded by a many-leaved involucre. 



C'al. adherent, often pappus-like, surrounded by a scarious involucel. 



Cor. tubular, somewhat irregular, the limb 4 — 5-parted. 



Sra. •!, alternate with the lobes of the corolla, often unequal. Anthers distinct. 



Ova. inferior, one-celled, oneovuled. Styleone, simple. 



Fr. dry, indehiscent, with a single suspended seed. 



Genera 6, species 150. The order is nearly allied to the Compositip. The species are all natives oi 

 the temperate regions of the Eastern continent, none of them American. Their properties are unimpor- 

 tant. One of the species below is useful in dressing cloth. 



1. DiPsAcus. 



Gr. Sixpacj, to thirst ; alluding to the water held in the axils of the leaves. 



Flowers in heads ; involucfe many-leaved ; involucel 4-sided ; calyx 

 superior; corolla tubular, 4-cleft ; fruit 1-seeded, crowned with the 

 calyx. — (D riants large, hairy or prickly. Lvs. opposite., connale (some- 

 times distind') at base. 



1. D. sYLVESTRis. Mill. Wild Tea.-^el. 



Z/ws. connate, sinuate or jagged; hds. cylindrical; brads of the involucre 

 longer than the head of flowers, slender and pungent, bent inwards. — A tali, 

 naturalized, European plant, growing in hedges and by road-sides, Mass. toia. ! 

 Stem about 4f liigh, angled and prickly, with the opposite, lance-shaped leaves 

 imited around it. Flowers bluish, in a large oval ox cylindrical head whose 

 bracts or scales are not hooked as in the next species, but straight. July. § 



2. D. FuLLONUM. Fullers' Teasel. — Lrs. connate entire or serrate ; Ar/. cylin- 

 drical; bracts \\o6ke& ; z«roZ. spreading. — A cultivated, European plant. Root 

 fleshy, tajfering. Stem erect, furrowed, prickly, hollow, about 5f high. Leaves 

 two at each node, united at their bases around the stem in such a way as to 

 hold a quantity of water. Flower;? whitish, in large, oval or ovoid heads. Cul- 



