NORTH CORRIDOR 99 



list of these in order from north to south is given on p. 145, 

 but we may draw attention to Solanum wendlandii; and to 

 Bougainvillea glabra, var. sanderiana, flowered in 1897. The 

 variegated variety of Arundo donax grows vigorously in the 

 bed under the wall. 



On the other side of the corridor, away from the wall, are 

 the Acanthaceous Hexacentris coccinea, and two specimens of 

 the India-rubber Tree, the Yam, Dioscorea macrura, Asparagus, 

 and Vitus plerophora a most instructive specimen, for the 

 stem has been cut away quite a foot from the ground, down 

 to which numerous adventitious roots have grown, which lie 

 on the surface like a tangled coil of string. The pink aerial 

 roots often exceed 12 ft. in length. 



Cyperus, Begonia, and Streptocarpus are planted out in 

 the border. 



Of other Yams there are the Otaheite Potatoe, Dioscorea 

 sativa, cultivated in India, and D. reticulata. The tubers 

 contain much starch and may increase to a weight of 50 Ib. 

 They are nearly related to the Elephant's Foot grown in 

 Green-house No. 12. 



Passiflora edulis yields a fruit like the Granadilla of tropical 

 America, from which a preserve is made. 



Ficus elastica, well known from pot specimens grown as 

 ornamental plants, is one of the principal sources of india- 

 rubber,* which exudes from its leaves and trunk as a semi- 

 liquid white juice, wherever an incision is made through the 

 epidermis. 



No. 5. THE FERN HOUSE 



The old collection of Tropical Ferns was contributed in great 

 measure by James Atkins, Esq., of Northampton. 



* Other sources of rubber are Hevea braziliensis or Siphonia elastica 

 of Central America, one of the Euphorbiaceae ; Castilloa elastica of 

 Mexico (Artocarpaceae) ; Landolphia, Willughbeia, and Urceola, Apocyna- 

 ceous plants from Malaya, Borneo, and Central Africa. Isonandra gutta 

 {Palaqnium gutta), Malaya, yields the well-known gdtta parcha. 



