200 BROOM-RAPES, BALANOPHOREiE, RAFFLESIACE^. 



the root upon which they are detained belongs to a Cissus plant, they germinate. 

 On the other hand, such Rafflesiacese as occur on the woody branches of trees, 

 shrubs, and undergrowths, or on lianes, develop succulent fruits, which are eaten 

 by animals. Their seeds are protected by a horny coat, and preserve their power of 

 germination unimpaired as they pass through the animals' alimentary canals and are 

 deposited with the excrements on the stems of fresh host-plants; or the seeds may 

 stick to some part of an animal that happens to rub against them, and be brushed 

 off later on as being an uncomfortable appendage, and in this way also they may 

 fall upon the stem of a host-plant. Those Rafflesiacese which occur in Venezuela on 

 the woody lianes (Caulotretus), known by the name of "monkey -ladders", owe their 

 dispersion for the most part probably to monkeys. 



Now, if a seed has been deposited in one way or another upon a woody root, 

 creeping along the surface of the ground, or upon the stem of a woody plant, the 

 filiform embryo emerging from the seed finds a suitable nutrient substratum present 

 and it pierces the cortex of the root, and develops beneath it a tissue, which incloses 

 the wood like a sheath. In Rafflesia and in the Pilostyles parasitic on the 

 sufiruticose shrubs of Tragacanth (P. Haussknechtii, see fig. 43 ^ ), this tissue consists 

 of rows of cells, which to the naked eye look like threads. Some are simple and 

 greatly elongated, others branched, and they are united together to form a net-work, 

 so closely resembling the mycelium of a fungus as to be readily mistaken for one. 

 The most complete similarity to these vegetative bodies living beneath the cortex of 

 a host-plant is exhibited by the mycelia of the toad-stools which spread themselves 

 in the form of nets and webs between the wood and the cortex of old trunks of 

 trees. The vegetative bodies of the other species of Pilostyles consist, in each case, 

 of a tissue composed of many layers of cells forming a parenchyma imbedded 

 between wood and cortex in the host-plant and including some vessels and rows of 

 cells capable of being interpreted as vascular bundles. Only in rare instances does 

 this tissue of the parasite form an unbroken hollow cylinder encompassing the 

 wood of the host; usually the elements of the host's tissues penetrate into it and 

 permeate and split up the cylindrical soma (vegetative body) in the form of bands, 

 ribs, and fibres. Many elements of the tissues, which the imbedded parasite has 

 displaced from the living wood, and carries, as it were, on its back, perish; but 

 sometimes these discarded layers remain in connection with other living tissues and 

 so preserve their own vitality and power of expansion, and develop layers of wood- 

 cells covering the parasite. There is then a general confusion and entanglement, 

 and it is difficult to say what part belongs to the parasite and what to the host. 



When the somatic tissue of the parasite has accomplished its connections with 

 the host-plant in the manner just described, the latter is unable to rid itself of 

 its occupant. A portion of the juices of the host-plant passes into the parasite's 

 cells and the unwelcome guest augments in volume, and endeavours forthwith to 

 reproduce and distribute its kind by the formation of fruit and seeds. For this 

 purpose buds are developed at suitable spots in the reticular body of the parasite, 

 each of which is manifested as a parenchyma of pulvinate appearance, and is 



