Nympkaacea^ flora indica. 237 



Wished ; and we have seen somewhat analogous instances in the growth of Fici and 

 Loranthacecs and Rhizophorea>, the plants of which are nourished by adventitious 

 roots, having no connection with that originally developed, which has died away. 

 Cuscuta otters another analogous case, as do those parasites which are supposed to 

 be developed first on other plants, but which afterwards are nourished by terrestrial 

 roots. 3. The absence of a cambium -layer, of bark, pith, and of a circular arrange- 

 ment of vascular structures. Of these points, the absence of pith and of the vascular 

 bundles forming a zone is exceptional in Victoria. The absence of a cambium-layer 

 is not a strong point, for there are many Exogens in which we have failed to trace it 

 in a normal condition, and there is as much a bark in "Nyrtrplueacea as there is in a 

 great many other Exogeus. 4. The isolated condition of the vascular bundles. This 

 perhaps requires confirmation, as it appeared to us that the bundles often united, 

 and, at any rate, there are various Exogens with isolated vascular bundles both in 

 the pith and bark. 5. There being no analogue to wood and liber. This appears to 

 militate equally against their Endogenous affinity, for the vascular bundles of Endo- 

 gens are composed of wood and liber, while those of Nymph&acea are not ; added to 

 which, we have seen that in Menispermea and AristolSehiea , and other Orders, the 

 liber is constantly absent, and in very many Orders qf Exogens the wood is wholly 

 replaced by vascular tissue. 



Our great objection, however, to all the above arguments, is their not bearing 

 strongly upon the question ; all ajjpear to argue an anomalous condition of Exoge- 

 nous stem, none at all approach to positive indications of the Endogenous, and we 

 need hardly say, that in a case of this kind the tendency is always to magnify the 

 importance of small deviations from a normal type, aud to seek to attach an ab- 

 solute value to them. Heufrey, however, states several objections to the Endoge- 

 nous affinity of Victoria, which, in an abstract point of view, seem as unanswerable 

 as the arguments in favour of the same affinity, but to which we do not attach any 

 importance, simply because their value as physiological and structural facts is as 

 much unknown as that of the others. These are: — 1. The vascular cord of each 

 root-bundle has not a central woody cylinder. 2. There is no fibrous layer between 

 the cortical and central substances. 3. The composition of the vascular bundles is 

 formed exclusively of ducts and unrollable spiral fibres. 4. The frequent anastomosis 

 of the vascular buudles, which is not commonly the case in Monocotyledones. — To 

 these we may add, as of far greater weight, the arrangements of the vascular bundles 

 on a longitudinal section, and that many of these run completely round the stem. 



Before dismissing this difficult subject, there are two theoretical considerations 

 which, we think, should not be overlooked : — 1. That assuming the rhizome of Kym- 

 phtea to be that of a Dicotyledon, a consideration of its habit, development, and mode 

 of growth would lead us to expect that its structure would deviate widely from the 

 type upon which it is formed ; bat that, assuming it to be a Monocotyledon, the con- 

 siderations in question would not lead us to expect in its rhizome so total a departure 

 from the type of that class. 2. That in a case of this kind, where the class to 

 which a group belongs is indicated clearly by the general structure and develop- 

 ment of its embryo, leaves, flowers, fruit, aud germination, and by direct affinity with 

 individual members of that class, it is much more philosophical to regard an appa- 

 rent exception in one organ a> reducible to an anomaly of the class with which the 

 group has a direct affinity, rather than an indication of affinity to that with which it 

 has otherwise none. We hence urge, as a fatal objection to the Endogenous affinity 

 of N rp/ueacerf, that there is no Order amongst Monocotyledons to which Treeul 

 or Heufrey has allied them, whilst there are many amongst Dicotyledons, with which 

 they accord in the structure of their foliage, perianth, fruit, aud seed. 



We sum up our reasons for considering Nymphaacea to be true Dicotyledons as 



follows : — - 



1. The structure of the embryo is truly Dicotyledonous, and resembles nothing 

 amongst Monocotyledons. 



2. The germination is strictly Dicotyledonooa and Exorhizal. The primary leaves 

 re an opposite pair, alternating with the cotyledons. 



