330 



SCIENCE-GOSSIP. 



Genital Plates are nearly circular, similar to 

 those of the female. 



Palpi are like those of the female, as shown in 

 fig. 34, with the exception that there is another 

 very short tactile hair between the two long 

 ones. 



Localities. — This mite is not common. I have 

 only taken about eight specimens in four years. 



IX. — Curvipes ambiguus Piersig, 1894. 



There is some doubt about this mite, Piersig 

 having named it from the nymph. It curiously 

 has three discs on each plate, whereas all the 

 other nymphs of this genus known at present 

 have only two. 



Genital Abea. — Fig. 36 will show the arrange- 

 ments of the genital plates. 



(D 



/ 



Fig. 36, C. amhiguus. — Genital area of nympli. 

 Localities. — Having found the nymph myself 

 at Staines in 1895, it should be included in our 

 British list. 



(To be continued.) 



SUCCULENTS AT KEW. 



Bt E. H. Wilson. 



AFOEMAL introduction to my subject seems 

 unnecessary, since the Succulent House is so 

 well known to all frequenters of the Eoyal Gardens 

 at Kew. Many are probably more interested and 

 amazed at the marvellous collection of plants 

 grouped together in this house, than in any of the 

 other departments of the gardens. It would seem 

 at first sight as if the authorities had determined 

 to group together in this structure all the prodi- 

 gies of plant life. The variety in form seems 

 endless and infinite. The enormously thick leaves 

 and terrible spinescent apices of the American 

 aloe (Agave), the columnar stems of giant cacti 

 armed with stout, horny spines, the huge cande- 

 labra Euphorbias, the remarkably articulated stems 

 of the " prickly-pear " ( Opuntia), covered with short, 

 barbed spines, and many other curious and gro- 

 tesque plants combined, have earned for this 

 house the seemingly appropriate name of the 

 " Chamber of Horrors," a name which has clung 

 tenaciou.sly to it for well-nigh half a century. 



The whole aspect of this house is so totally 

 different from its neighbours that it cannot fail to 

 attract and impress even the most casual observer. 

 To the average visitor it is simply a mviseum of 

 vegetable curiosities. To the gardener, the gor- 

 geous and beautiful flowers of Phyllocactus and 

 Epiphyllum, the great white flowers of the "night- 

 flowering Cereus," often a foot in diameter, and 

 the graceful habit of species of Asparagus, will 

 strongly appeal, if other things fail. To the 

 botanist, the whole house is a veritable treasure- 

 trove. The entire collection is one huge demon- 

 stration of that marvellous phenomenon known as 

 plant metamoi'phism. Nearly every species shows 

 the same organs modified in diverse ways and 

 in varying degrees, all apparently with the 

 ooject of better subserving their function in the 

 plants' economy and aiding in ensuring the per- 

 petuation of the species. As an evolutionist the 



botanist here finds some of the strongest evidence 

 extant of adaptation of plants to environment. 



Practically all the inhabitants of this large 

 house (200 ft. by 30 ft.), are xerophytes — that is 

 to say, plants which inhabit dry regions. As one 

 would natiu-ally expect, we find xerophytic repre- 

 sentatives of many different families of plants, 

 but the great majority belong to the foUo^ving 

 seven natural orders : Liliaceae, Amaryllideae, 

 Cactaceae, Euphorbiaceae, Crassulaceae, Asclepia- 

 deae, and Compositae. Nearly every arid region 

 of the tropical and sub-tropical parts of the globe 

 is represented by the plants in this house ; but 

 the majority are concentrated in two widely- 

 separated geographical areas, of South Africa on 

 the one hand, and Mexico, Texas, Arizona, and 

 Peru on the other. To the former belong the 

 majority of the Liliaceae, Euphorbiaceae, Crassu- 

 laceae, Asclepiadeae and Compositae ; to the 

 American continent the Cactaceae and Amarylli- 

 deae. The insular flora of the Canaries is well 

 represented by various species of Sedum, Crassula, 

 and Euphorbia. Of the remaindei-, Abyssinia, 

 Somaliland, and Australia claim a share. Par- 

 ticu.larly noteworthy are the grass-trees or black- 

 boys (Xanthorrhaea) of Australia. The prickly 

 pear, and Amei'ican aloe, have been largely intro- 

 duced and planted in the Canaries, Mediteranean 

 region, India, and South Africa. The former is 

 esteemed by many for its fruit, whibh is acid and 

 pulpy ; but in the Canaries the plant is used as 

 food for the cochineal insect. The aloe yields 

 valuable fibre, and is cultivated for this in India. 



In the regions enumerated, the average rainfall 

 i s very small, and in parts of Mexico rain may not 

 fall for two or three years. Any plant to exist 

 under such adverse conditions must certainly pos- 

 sess special and peculiar structural adaptations 

 whereby transpii-ation or loss of water, due to the 

 action of the sun's rays, is reduced to a minimum. 



