Tropics, especially in Asia ; a few occur in 

 North America. [J. T. S.] 



CISTACEJE. (Rock-rose family.) A natural 

 order of thalamifloral dicotyledons, cha- 

 racterising Lindley's cistal alliance. 

 Shrubs or herbs, often viscid, with sim- 

 ple entire leaves and showy flowers. 

 Sepals three to five, persistent, unequal, 

 The three inner twisted in the bud. 

 Petals five, rarely three, falling off, often 

 crumpled, twisted in an opposite direction 

 from the sepals. Stamens numerous, not 

 united. Fruit a one-celled capsule with pa- 

 rietal placentas, or imperfectly three to five- 

 celled with central placentas. Seeds with 

 mealy albumen; embryo curved or spiral. 

 The plants are found chiefly in the south 

 of Europe and north of Africa. They are 

 very rare in North America, still more un- 

 common in South America, and scarcely 

 known in Asia, They are usually resinous, 

 and have a balsamic fragrance. The resin 

 called Ladonum is procured from several 

 species of Cistus. Helianthemum vulgare, 

 the common rock-rose of Britain, has re- 

 markably irritable stamens, which in 

 sunny weather move on being touched. 

 There are eight known genera, and about 

 190 species. Illustrative genera: Fumana, 

 Cistus, Helianthemun, [J. H. B.] 



CISTELLA, CISTULA. A cell-like shield 

 found among lichens in the genus Sphcero- 

 phoron. 



CISTCOIE. ' A membranous sac which 

 according to some, penetrates stomates, 

 and reaches the bottom of the subjacent 

 chamber. If this statement is correct the 

 cistome must be a fold of the cuticle. 



CISTOPHORUM. The stipe of certain 

 fungals. 



CISTOPTERIS. A mode of spelling 

 which is sometimes adopted instead of 

 Cystopteris. [T. MJ 



CISTFS. A genus of the rock-rose 

 family, to which it gives the name, com- 

 posed, of handsome shrubs, many of them 

 in cultivation, natives of Southern and 

 Western Europe, North Africa, and the 

 Canary Islands. They are commonly known 

 as Rock-Roses and Gum Cistus, but the 

 latter name is the better of the two, as 

 the former is equally applied to Helianthe- 

 mum, from which this genus differs in 

 l having an imperfectly five or ten-celled 

 i capsule, while in Helianthemum the eap- 

 I sule is imperfectly three-celled. The 

 greater portion of the species are elegant 

 , erect bushes, with opposite entire or some- 

 I times toothed leaves, generally oblong 

 j or lance-shaped, and axillary or terminal 

 j flower-stalks bearing one or many flowers. 

 These are made up of a five-leaved calyx, five 

 large petals, numerous stamens, and an 

 ovary crowned with a simple style. The 

 , flowers of all are handsome, and many of 

 them in size and appearance resemble 

 j those of the dog-rose; they seldom last 

 I more than a few hours after expansion, 

 I and do not open in dull weather when 

 there is no sunshine. In one group of 



species the petals are white and furnished 

 with a yellow or purple mark at their base ; 

 while in a second the petals are rose- 

 coloured, each with a yellow spot at its 

 base. None of them have yellow flowers, 

 a colour so common among the Heli- 

 antlicmums. 



The Ladauum or Labdanum of Crete is 

 a well-known gum, which exudes from the 

 leaves and branches of C. creticus, and 

 some other allied species. This plant is a 

 handsome shrub, with oblong obtuse 

 rough leaves with waved margins and 

 about an inch in length. The flowers are 

 terminal and single or twin, the petals 

 purple with a pale yellow spot at the base. 

 The gum is collected in Crete by means 

 of a kind of rake, ' with a double row of 

 long leathern straps, employed in the heat 

 of the day when not a breath of wind is 

 stirring. Seven or eight country fellows, 

 in their shirts and drawers, whip the 

 plants with these straps, which, by rub- 



Cistus creticus. 



bing against the leaves, lick off a sort of 

 odoriferous glue sticking to the foliage.' 

 ! Formerly it was said to be gathered from 

 ! the beards of goats, which are fond of 

 browsing on the foliage of the plant. The 

 gum, by gently rubbing in the hands, 

 emits a very pleasant balsamic odour, from 

 the presence of a volatile oil. It was once 

 used in time of the plague as a stimulant 

 i and expectorant, and as a constituent in 

 plaisters. About fifty hundredweight of 

 it is annually sent from Crete to Turkey, 

 where it is used as a perfume, and as a 

 fumigation. The Ladanum of Spain and 

 Portugal is derived from C. ladaniferus. 

 This is one of the most beautiful of the 

 genus, and is very frequently to be met 

 in gardens. In Portugal it is said to 

 cover leagues of country. Its leaves are 

 i lance-shaped, entire, and three-nerved, the 

 ! upper surface covered with a clammy 

 ; gluten, and the under surface prominently 

 ; three-nerved and covered with a dense 

 white tomentum. The large white flowers 

 are sometimes more than three inches 

 across in one variety, the petals having a 

 1 deep purple blotch at the base. The gum 



