PARASITES AND SEEDLINGS COMPARED. 373 



serve for the production of an organism of an entirely different kind, whence it is 

 perceived that, in nutrition, it depends by no means simply upon the chemical nature 

 of the food-materials, but far more upon the inherited nature of the species of plant. 

 The majority of phanerogamous parasites are connected with their host-plant 

 only by means of small haustoria : the rest of the body lies outside the host. All the 

 organic substance from the host-plant must now pass over to the parasite through 

 this relatively small surface of the haustoria. as is conspicuously the case in the 

 Orobanchese and Cuscuteae. But it is just in this apparently most difficult point 

 of parasitism that the plants in question agree with the seedlings of normal 

 plants : the embryos of seeds provided with an endosperm also take up the whole of 

 their nourishment from the endosperm by means of special haustoria, which in this 

 case are always parts of leaves. An uncommonly clear example illustrating what 

 has been said has already been given in the case of the Date seedling (p. 344). The 

 same may be said of the Grasses, the haustorium of which is usually termed the 

 scutellum by botanists: I have referred to this on p. 38 (Fig. 28; cf. Fig. 35). 

 Moreover, most Monocotyledons afford similar examples of the absorption of the 

 endosperm by a haustorium of the seedling'. Probably the most striking case is 

 that of the germinating Cocoa-nut, the tiny embryo of which, when it begins to grow, 

 developes at the apex of its first leaf a haustorium resembling that of the Date 

 seedling : this subsequently attains the size and form of a turnip, in order to absorb the 

 nutritive materials contained in the huge seed. In these cases it is peculiarly organised 

 haustoria on the leaves of the seedling which absorb the substances of the endosperm 

 at their surfaces, and transfer them to the seedling : in many other cases, especially 

 in the Coniferse and some Dicotyledons {Ricitius e.g.), the cotyledons themselves, 

 which develope subsequently into normal green leaves, accomplish this. In all such 

 cases, however; the seedling acts like a parasite, which by means of peculiar organs 

 absorbs its nourishment from a vegetable body (the endosperm) filled with reserve- 

 materials. The most conspicuous difference, in contrast to the haustoria of parasites, 

 consists in that the absorbing organs of seedlings are only slightly in contact with the 

 endosperm, and by no means organically connected with it ; whereas, as already 

 stated, the haustoria of parasites become so intimately connected with their host- 

 plants, that it is often difficult to decide where the boundary between the two lies. 

 Parasites have therefore in this respect an advantage over normal seedlings ; they 

 behave towards their host-plants rather like the buds of a germinating tuber or bulb. 

 Just as the assimilated nutritive substances pass over from the endosperm, or from the 

 tissue of a tuber or rhizome, into the seedling shoots, etc., the assimilated materials of 

 the host-plant also can pass over into the haustorium of the parasite ; and just as it 

 is from the seedling of a seed, or the sprout of a tuber, that the force for transferring 

 the reserve-materials into its tissues proceeds, so the parasite possesses the forces 

 for extracting and storing up in itself the assimilated materials from the tissues of the 

 host-plant. If this takes place in the case of seedlirigs by the excretion of ferments, 

 however, we can scarcely doubt that ferments are also formed in the haustoria 

 of parasites, and transferred into the tissues of the host-plant. In Cuscuta I have 

 had the opportunity of convincing myself that the starch stored up in the tissues 



1 Cf. my treatise, ' Uchcr die Keimung des Samens von Allium Ce/ti,' Bot. Zcitg., 1S63 (p. 57). 



