84 RHIZOGENS. 



Fungals. In Cynomorium, Scybalium and Balanophora, this part is wanting, 

 and in its room the roots of those genera emit roundish deformed tubers 

 collected in a circle upon the roots of other plants, and growing into them 

 by some unknown process, Blume says, " that at the period of germination 

 of Balanopliore£e there is produced from the roots of the Fig on which they 

 grow an intermediate body, of a fleshy nature and intimately combined with 

 its superficial woody layers, and that this intermediate body is penetrated 

 by their spiral vessels, which render it woody." He moreover adds, that 

 " several seeds of Balanophoreae germinate on nearly the same points of the 

 Fig-root ; hence this woody body, or luxuriant product of the juices that are 

 sucked out, has generally an irregular form, and the plants proceeding from 

 such tubers grow out in diflerent directions, much in the same manner as the 

 tubers of a Potato generate their offsets : with this difference, however, that 

 in a Potato the eyes of the plant are in the circumference, while in Balano- 

 phora they are placed in the centre, and on that account the intermediate 

 body where the oft'sets break out, has necessarily a conical extension." 

 Something of the same kind occurs in Scybalium, whose tubers are expanded 

 in an irregular form about the root of some unknown tree, are fleshy, and 

 composed even in the substance of the stalk of somewhat irregular cells and 

 no spiral vessels. In the room of leaves these plants have scales, which 

 differ from true leaves in the want of colour, a character common to all other 

 plants parasitical on roots. A vertical stalk (stipes), sometimes terminated 

 by a solitary head of flowers, sometimes bearing several heads variously 

 arranged upon the stalk, is found in all the genera of Balanophoracete ; which 

 moreover agree in this that the flower-heads, which at first are sessile on the 

 rhizome and concealed by many rows of imbricated scales, resemble the 

 leafy rosette of a Sempervivum without colour, or rather the very small bud 

 of a Rafliesia. The genuine species of Helosis show on their rhizome 

 roundish conical buds seated on a very short stalk, or altogether sessile, 

 enclosing the rudiments of the future head within a very thin involucre, as a 

 fungus within the volva ; this latter after a time sphts into three or more 

 segments, and emits the flower-head enlarged and furnished with a stalk, 

 which is altogether naked except at the base, where it is surrounded by 

 the scale-like segments of the withering involucre. This is the most simple 

 form of involucre, which in the other genera becomes more and more com- 

 plicated, and finally runs into numerous series of imbricated scales which 

 clothe the stipes more or less completely. In those genera which grow upon 

 the bark of the stems of trees, there are some diversities of structure in the 

 organs of vegetation that are very remarkable. Blume tells us that Rafflesia 

 Patma appears upon the creeping roots or stems of Cissus scariosa in the 

 form of solitary or clustered hemispherical dilatations, which look like 

 excrescences or expansions of the root. These excrescences are something 

 of the nature of leaf-buds, consisting of layers of scales and a more solid 

 centre. As the latter increase in size they burst through the wrapper by 

 tearing it irregularly from the apex towards the base, and develop them- 

 selves in the form of numerous scales, at first flesh-coloured, then brownish, 

 and finally deep purple, which surround the flowei*s. As soon as these parts 

 are exposed, richly nourished as they are by the humid air that surrounds 

 them, they grow with such raj^idity that it is reported that Rafliesia, which, 

 when full-blown, is a yard across, and when unexpanded, is as large as a 

 middle-sized cabbage, only takes about three months for its complete forma- 

 tion. Brugmansia has a similar mode of develoj)ment. 



At one time it was believed that Rhizoft'cns agreed with Fungals in tlie 



