393 



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thistles, from which they are, however, 

 easily recognised by their tawny pappus 

 hairs, those of sow-thistles being silvery 

 white. The stems seldom exceed twelve 

 feet in height. The leaves vary much in 

 form and size, some being entire and two 

 or three inches long, while others are afoot 

 or more in length, and pinnatifld. The 

 flower-heads few and large in some, or nu- 

 merous and small in others, are arranged 

 in terminal panicles, and the numerous 

 florets are either of a white or tawny-yel- 

 low colour. The achenes, compressed or 

 triangular with winged angles, are crowned 

 with a pappus of rough unequal hairs. 



The most striking species of the genus 

 is B. macrantha, whose lower leaves are 

 stalked, oblong, coarsely toothed, and ob- 

 tuse, while the upper ones are small and en- 

 tire, and clasp the stem by their base. The 

 flowerheads are more than an inch in dia- 

 meter. Seven species are enumerated. 

 The name Rea is sometimes given to these 

 plants. [A. A. B.] 



DEXHAMIA. A genus of tropical Aus- 

 tralian trees or shrubs of the spindle-tree 

 family, chiefly distinguished by their bony 

 capsules and numerous seeds. Their pale- 

 green stalked leaves are oval or lance- 

 shaped, and have entire or spiny margins. 

 The flowers are small, green, arranged in 

 terminal panicles, and have a five-cleft 

 calyx, five petals, and Ave stamens, in- 

 serted on a sinuate fleshy ring. The fruits 

 are imperfectly three or five-celled bony cap- 

 sules, the seeds being enveloped in a beau- 

 tiful red aril. B. heterophylla has some of 

 its branches furnished with lance-shaped 

 entire leaves, and others with oval leaves 

 having spiny teeth like those of the holly. 

 Five species are known. [A. A. BJ 



DENNISONIA. The only species of this 

 genus, which belongs to the vervain 

 family, is B. temifoUa, a North Australian 

 bush,with straight stems clad with glandu- 

 lar hairs, and a great abundance of mint- 

 like leaves, which are sessile, oval and 

 sharply toothed. The little rose-coloured 

 flowers are single in the axils of the leaves 

 and shortly stalked, the corollas being two- 

 lipped. The genus bears the name of Sir 

 W T. Dennison, governor of New South 

 Wales. [A. A. B.] 



DENNST.EDTIA. A genus of herbace- 

 ous ferns of the group Bickfoniece, distin- 

 guished from Bicksonia itself, chiefly by 

 having a cup-shaped instead of a two- 

 valved indusium, this being reflexed so as 

 to stand at a right angle to the plane of 

 the frond. They have creeping rhizomes, 

 and for the most part large herbaceous 

 bipinnate or decompound fronds. B. punc- 

 t'dohvla , I), cicutaria, B. apiifolia, &c, are 

 familiar examples. The same group has 

 been sometimes called Sitobolium, or by 

 error Sitolobium. [T. M.] 



DENS. A toothing ; adj. DENTATE : 

 having sharp teeth with concave edges. 

 When these teeth are themselves toothed, 

 the part is duplicato-dentate : not bidentate, 

 which means two-toothed. 



DENTARIA. A family of herbaceous 

 perennials belonging to the Gruciferce, and 

 closely allied to Cardamine, from which it 

 differs in having broad seed-stalks, and in 

 its creeping roots being singularly toothed; 

 hence the systematic name, and the Eng- 

 lish one of Toothwort. Thei'e are many 

 species, which inhabit mostly the tempe- 

 rate regions of Europe and America, and 

 are ornamental plants with terminal 

 corymbs of light purple, sometimes white 

 or yellow flowers. The roots of B. diphyUa 

 have a pungent mustard-like taste, and 

 are used by the natives of the mountains 

 of North America, from Pennsylvania to 

 Canada, instead of mustard, under the 

 name of Pepperwort. The genus is repre- 

 sented in England by B. bulbifera, a slender 

 plant about eighteen inches high with pin- 

 nate leaves and a few pretty light purple 

 flowers. In the axil of every stem-leaf is a 

 small bulb of a purple hue, by which the 

 plant, which rarely perfects seeds, is propa- 

 gated. Though local it is very abundant in 

 some of the woods of Hertfordshire, creep- 

 ing extensively by means of its curiously 

 toothed white roots, and forming dense 

 patches. The root-leaves are all pinnate, 

 those of the stem pinnatifld, the upper 

 ones nearly simple. [C. A. J.] 



DENTATO-CRENATE. The same as Cre- 

 nato-dentate. 



DENTATO-LACINIATE. When tooth- 

 ings are irregularly extended into long 

 points. 



DENTATO-SERRATE. When toothings 

 are taper-pointed and directed forwards, 

 like serratures. 



DENT DE CHIEN. (Fr.) Eryfhronium 



Bens Cards. 



DENT DE LION. (Fr). Taraxacum Bens 

 Leonis. 



DENTELAIRE. (Fr.) Plumbago euro- 

 pcea. 



DENTELLA. Little creeping annuals, 

 natives of marshy places in India and the 

 Indian Islands, constituting a genus of 

 CinchonacecB. The flowers are small.white, 

 on axillary flower-stalks, with a roundish 

 hairy calyx-tube united to the ovary ; the 

 limb of the calyx is five-cleft ; the corolla 

 is funnel-shaped with a dilated throat, its 

 limb five-cleft, each of the petals having 

 on either side a small acute tooth-like pro- 

 cess ; the stamens are concealed within 

 the corolla; and the fruit is a two-celled 

 berry, surmounted by the lobes of the 

 calyx. [M. T. M.] 



DENTICULATE. Having very fine mar- 

 ginal teeth. 



DENUDATE. When a surface which 

 has once been hairy, downy, &c, becomes 

 naked. 



DEODAR. Abies, or Cedrus, Deodara. 



DEOPERCULATE. A term used in de- 

 scribing mosses, when the operculum will 



