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Thus there are certain palms which possess green, juicy leaves, much relished by snails. These are protected by a sort of spine entanglement formed upon certain roots, which grow at the base of the leaves. Nor is this the only case in which spines are found on roots. There are certain South African bulbs (_Moræa_) which are protected from the wild pigs by a dense mass of spiny roots.[81] On my march to Uganda from Mombasa, I was very much astonished to see an extraordinary Wild Yam. It had a huge underground tuberous part full of starchy matter, but it was quite impossible for any marauding wild boar to get at it, for it was entirely enclosed in a sort of arbour of long, arching roots densely covered by stout spines, which made a perfect protection.[82]