192 BROOM-RAPES, BALANOPHORE.E, RAFFLESIACE^. 



the whole mode of growth. The phenomena of the swelling of the embryo into a 

 tubercle after it has chanced upon a nutritive root, the destruction of the cortex, 

 the exposure of the wood at that part of the root where the tubercle is adnate, and 

 the derangement of the course of the woody bundles ensue, it is true, in the same 

 manner as in the other Balanophorese ; but the frayed wood-bundles of the foster- 

 root only form quite short lobules which penetrate but a short distance into the 

 parasitic tuber-stock, whilst the vascular bundles, formed meantime in the latter, 

 adhere to them in such a manner that they might be mistaken for direct continua- 

 tions of them. 



When once the parasitic tubers have thus become adnate to a root, and by 

 means of this union are provided with food, they grow round the nutrient roots in 

 such a way that the latter appear to perforate or actually to issue from the 

 tubers. They are always roundish, brown outside, and warty, but without 

 scales, and they never produce inflorescences directly, but put forth in the first 

 place several whitish or yellowish runners varying in thickness from a quill to a 

 finger, which creep along horizontally under the ground, bifurcating, and becoming 

 interlaced with other ramifications. At the places of contact they coalesce, and so 

 occasionally form a net-work which is almost inextricably entangled with the root- 

 system of the plant preyed upon. Whenever a runner of this kind comes into 

 contact with a living root belonging to the host -plant, the surface of contact at once 

 swells up. The part afiected is converted into a tuberous mass and becomes adnate 

 to the root, the process being the same as occurs in the case of the tubercle pro- 

 duced from seed, A net-work of runners thus connected with the root-system of 

 the nutrient plant at several spots by means of tubers as large as peas might be 

 compared to the reticulum woven by Lathrcea round the roots of its hosts; but, 

 apart from the size, there is the essential difference that inflorescences are never pro- 

 duced from the white threads of the ramifying and sucker-bearing roots of Lathrcea, 

 whereas the runners of Helosis afford points of origin for new inflorescences. Warts 

 are produced on the surfaces of the thicker cylindrical runners, and within these 

 are developed the buds of the inflorescences. The outer coat of the warts is then 

 rent open at the top and constitutes a little cup, out of which grows a naked, scale- 

 less shaft terminated by an oval spadix. Seeing that the runners rest horizontally 

 under the earth whilst the shafts ascend bolt upright from the ground, the latter 

 are always at right angles to the runners, of which they are to be regarded as 

 branches. 



The flowers are grouped in capitula, presenting in the spadix a dense mass. 

 They are protected by peculiar bract-scales, each of which by itself is like a nail 

 with a facetted head. These heads are in close contact with one another, so that 

 the young inflorescence seems to be inclosed in a panelled coat of mail, and 

 resembles to a certain extent a closed fir-cone. By degrees, however, these bract- 

 scales detach themselves and fall off", and thus the flowers, till then roofed over by 

 them, become visible. When the seeds are mature, the whole runner concerned in 

 the production of the inflorescence, and usually also the tuber which served as the 



