DIG 



DID 



honour of Mr. James Dickson, a genus of 

 the Cryptogamia Filices class and order. 

 Natural order of Filices, or Ferns. Ge- 

 neric character: fructifications kidney- 

 shaped, lying under the edge of the 

 frond at the lower surface ; outer valve 

 formed of the substance of the leaf itself; 

 inner membranaceous ; involucre double, 

 one from the surface, opening outwards ; 

 the other from the inflated margin of the 

 frond, often embracing the former, open- 

 ing inwards. There are thirteen species, 

 D. arborescens, tree dicksonia, was 

 found by Sir Joseph Banks in the island 

 of St. Helena. It flowers most part of the 

 winter. And D. culcita, shining leaved 

 dicksonia, is found in the island of Madei- 

 ra, where it is called feila brom. The 

 inhabitants make pillows and cushions of 

 the roots. It is supposed (Phil. Trans. 

 1698) that this plant and the Scythian 

 Lamb are one and the same, though they 

 come from countries so remote. 



DICOTYLEDONS, plants whose seeds 

 have two side-lobes, and consequently 

 rise with two seminal leaves. Most 

 plants are of this kind. See COTTLE- 



OONS. 



In the lip and masqued flowers, the 

 didynamia of Linnaeus, and in plants 

 whose seed-vessel is of the apple, cher- 

 ry, or pod kind, the seed leaves rise unal- 

 tered ; that is, without any farther ex- 

 tension or developement than when they 

 made part of the seed. In the mallow, 

 and the cross-shaped flowers, they ap- 

 pear double ; in buck-wheat they are 

 rolled up ; in cotton, folded or plaited ; 

 in salt-wort and all the pot-herbs, they 

 are spiral, or twisted like a screw. 



DICRAN1UM, in botany, a genus of 

 the Cryptogamia Musci class and order. 

 Capsule ovate, oblong; fringe simple, 

 of sixteen broadish, inflected, cloven 

 teeth. This is a very numerous genus, 

 divided into two sections: A. teeth of 

 the fringe unconnected at the base ; B. 

 teeth of the fringe connected at the 

 base. 



DICTAMNUS, in botany, English/rax- 

 inellfi, a genus of the Decandria Monogy- 

 nia class and order. Natural order of 

 Multisiliqux. Rutaceae, Jussieu. Essen- 

 tial character : calyx five-leaved ; petals 

 five, patulous ; filaments having glandu- 

 lous dots scattered over them ; capsule 

 five, conjoined. There are two species, 

 of which D. albus, fraxinella, has a pe- 

 rcnnial root, striking deep into the 

 jground, and the head annually increas- 

 ing in size; stalks many, two or three 

 feet high ; flowers in a long pyramidal 

 loose spike, or raceme, nine or ten in- 



ches long ; calyx deeply five-cleft ; seg- 

 ments lanceolate, obtuse, the three up- 

 per red, the two lower green ; corolla 

 large and handsome ; the natural colour 

 pale-purple, with dark purple veins, va- 

 rying to white. The whole plant, espe- 

 cially when gently nibbed, emits an 

 odour like that of lemon-peel; when 

 bruised it has something of a balsamic 

 scent : this scent is strongest in the pedi- 

 cles of the flowers, which are covered 

 with glands of a rusty red colour, exuding 

 a viscid juice or resin, which exhales in 

 vapour, and in a dark place may be seen 

 to take fire. Fraxinella is a native of 

 Germany, France, Spain, Austria, and 

 Italy. It flowers with us about the end 

 of May, or early in June ; the seeds ripen 

 in September. For its beauty and fine 

 scent it deserves a place in every good 

 garden. 



DICTIONARY, a collection, or cata- 

 logue of all the words of a language, art, 

 science, &c. with their explanations, 

 ranged in alphabetical order. 



DIDELPHIS, the opossum, in natural 

 history, a genus of Mammalia of the or- 

 der Ferae. Generic character : fore-teeth 

 small and rounded ; upper, ten small and 

 rounded ; intermediate, two, longer ; 

 lower, eight, intermediate two, broader 

 and very short ; tusks long ; grinders 

 denticulated ; tongue fringed with papil- 

 lae ; abdominal pouch, in most species, 

 containing the teats. 



These animals first became known to 

 Europeans on the discovery of America, 

 and excited their particular attention by 

 a deviation in their structure from that of 

 all other known quadrupeds. This sin- 

 gularity consists in the female's posses- 

 sion of a bag or pouch in the lower part 

 of the abdomen, which is opened and 

 closed at pleasure, and to which her 

 young resort for shelter and security in a 

 variety of dangers. Some females pos- 

 sess, according to Gmelin, two or three 

 of these pouches, and the male is stated 

 also, in the same author, occasionally to 

 have one. These animals live in the 

 woods, bun-owing in the earth, and, by 

 means of a prehensile tail, are alert in 

 climbing trees. Their general motion is 

 slow, and their food consists of insects, 

 worms, and vegetables, young birds, and 

 particularly poultry. They are by no 

 means peculiar to the Western continent, 

 but are to be found in various other parts 

 of the world. According to both Shaw 

 and Gmelin, there are twenty-one spe- 

 cies, of which the following are most de- 

 serving of attention : for the spotted 

 opossum, see Mammalia, Plate IX. fig. 1. 



