248 



THE POPULAR EDUCATOE. 



description of which we shall terminate this notice of the family 

 Qompositce. 



The genus dahlia is characterised by having an involucrum of 

 which the exterior bracts, about five in number, are reflexed, 

 and the internal ones, from twelve to twenty in number, arranged 

 in double series, are membranous at their summit, thick and 

 fleshy at their base. The achsenia, or fruit, are surmounted by 

 two short points. The stem is herbaceous ; leaves opposite and 

 pinnatifid. The species most cultivated in our gardens, which 

 it embellishes during the autumn, is the Dahlia coccinea, or 

 ordinary scarlet dahlia. It is a native of Mexico, whence it was 

 transported to Spain about 1790, and a specimen was sent from 

 Madrid to France in the year 1802. At first the French gardeners 

 cultivated it as a greenhouse plant, but they soon discovered the 

 dahlia to be capable of flourish- 

 ing in the open air. From this 

 time the plant was rapidly dis- 

 seminated, and many varieties 

 began to appear. The flowers of 

 the primitive species were all 

 simple, the disc yellow, the rays 

 arranged in two series, dark 

 scarlet and velvety in appear- 

 ance. In 1810 varieties sprang 

 up, having lilac, rose-coloured, 

 and saffron-yellow rays. In 

 1818 double-flowered varieties 

 were obtained, possessing cornet- 

 shaped tubular florets, consti- 

 tuting an imbricated rose. Since 

 then so many varieties have 

 sprung up, that their mere enu- 

 meration would be impossible. 



SECTION XL.VALEKIANA- 

 CE.ffi, OB VALEEIAN WORTS. 



Characteristics : Calyx adhe- 

 rent to the ovary ; corolla mono- 

 petalous, epigynous ; stamens 

 ordinarily less numerous than 

 the lobes of the corolla, and 

 adherent to its tube. Ovary 

 three-celled, two of which cells 

 are barren, the third containing 

 one seed ; ovule pendant ; seed 

 dicotyledonous ; radicle superior. 



The Valerianacece, which de- 

 rive their name from the valerian, 

 one of the principal genera, are 

 either herbs, with slender roots, 

 or perennials, having an almost 

 woody rhizome, generally con- 

 taining odorous matter. The 

 radical leaves ar tuft-like, 

 petiolate, simple, opposed, and 

 without stipules. 



The flowers of most of the 

 Valerianacece contain both pistils 

 and stamens, though certain 

 members are monoecious, others 

 dioecious. Usually the inflorescence is a cyme, sometimes a 

 corymb. The tube of the calyx is attached to the ovary ; the 

 limb of the calyx divided into three or four parts. The corolla, 

 inserted into the margin of a disc crowning the ovary, is tubular, 

 and shaped like a funnel. Its tube is often spurred at the base, 

 its limb generally divided into five lobes, and sometimes irregular. 

 The stamens inserted upon the tube of the corolla alternate with 

 the divisions of the latter. Their number is rarely five, more 

 frequently four, the fifth being suppressed ; sometimes three, 

 by the suppression of the lateral stamens. Lastly, in certain 

 cases only a single stamen becomes developed. The anthers 



176. THE FLOWERS, LEAVES, AND KOOT OF THE DAISY. 177. 



PISTILLIPEBOUS BAY - FLOEET OF THE DAISY. 178. PERFECT 

 DISC FLORET OF THE DAISY. 



embryo straight; cotyledons oblong, exceeding in length the 

 radicle. The Valerianacece are, for the most part, inhabitants of 

 the ancient continent, being chiefly found in Central Europe 

 and the Mediterranean region, and the Asiatic district of the 

 Taurus and Caucasus, from which a few species have wandered 

 to Nepaul, and Siberia, and Japan. In the tropics they are un- 

 known, except in certain mountainous regions. In Chili and 

 Magellan several species are not unf requent ; but North America 

 only possesses one. 



The Valerianacece are a natural order concerning the medicinal 

 qualities of which all persons are agreed. The active principles 

 are a volatile oil, and an acid termed the valerianic acid, which 

 chemists now make artificially. The perennials are more effi- 

 cacious than the annuals, probably because in the latter the 

 active principles have not had 

 sufficient time to develop them- 

 selves. The smell of the valerian 

 is very peculiar ; some people 

 think it agreeable; a far greater 

 number, however, are of a con- 

 trary opinion. Amongst cats 

 there is no such difference of 

 sentiment. These animals are 

 very partial to the odour of the 

 valerian, and eagerly scratch up 

 such plants of it as they meet 

 with in their rural explorations. 

 Valerian is now employed by 

 physicians in the cure of spasms ; 

 formerly its employment was 

 directed to the cure of the far 

 graver disease, epilepsy. Eeport 

 states that a Neapolitan noble, 

 who lived in the sixteenth cen- 

 tury, being a great sufferer from 

 epileptic attacks, and deriving 

 no advantage from physicians, 

 set about learning botany, in 

 order that he might discover the 

 medicinal properties of veget- 

 ables, and thus become his own 

 doctor. Notwithstanding the 

 common proverb, that the man 

 who is his own doctor has a fool 

 for his patient, the Neapolitan 

 did not study botany in vain. 

 After trying a kost of plants, he 

 at length alighted on valerian, 

 and cured himself of epilepsy. 

 Without intending any dispa- 

 'ragement to the skill and perse- 

 verance of this resolute gentle- 

 man, it may be permitted to 

 hazard a doubt whether the dis- 

 ease which afflicted him was 

 really epilepsy. 



Let us now proceed to an 

 enumeration of the principal 

 Valerianacece, commencing with 

 the Valeriana officinalis, which 



is the species most commonly employed. This plant is generally 

 distributed throughout Europe, where it frequently grows in 

 humid meadows, rarely in dry and sandy places ; its stem is 

 furrowed, its leaves pinnate and covered with down. The 

 Valeriana Phu is a German species, cultivated in our gardens, 

 the radical leaves of which are simple and lanceolate, the flowers 

 white. Valeriana Sichensis is a North American species, and 

 valued beyond every other by the Eussians. The ancients 

 vaunted the medicinal qualities of the Celtic and Indian nard. 

 The former (Valeriana Celtica) grows on the mountain sum- 

 mits of Styria and Carinthia ; the latter is a native of the 



are bent inward ; the ovary inferior, composed of three Alps. Both are still the objects of a very considerable com- 

 carpels, forming three cells, two of which are empty, the merce, large quantities being sent every year to Turkey and 

 third alone fertile. The ovule is reflexed, and hangs from I Egypt from Trieste, whence they find their way to the interior 

 the cell ; the style is simple filiform, terminated by two or ' of Africa and India. 



three stigmas, which are sometimes coherent into one. The 1 1 The Indian nard, or spikenard of the ancients, was in great 

 fruit is dry, indehiscent, ordinarily unilocular by disappearance j favour ; not that it was exactly a medicine, but it was thought 

 of the barren cells ; never containing more than one seed : to secure the affections of any lady or gentleman towards one 



