236 I'LOEA INDICA. [Nympliaacea . 



aware, been worked out ia a comprehensive manner, — that is, with reference to the 

 germination of all Natural Orders. Lindley, on the other hand, cites the fact of the 

 bases of the cotyledons elongating and emerging in germination, as "perhaps one of 

 the strongest arguments in favour of the lobes of the embryo being really cotyle- 

 dons." 



3. Bhizome. The true anatomy and structure of this organ is one of the most difh- 

 cult possible to demonstrate, nor do we profess to understand it thoroughly. AVc 

 have attempted to trace the courses of the vascular bundles in N. pygmcea, Lotus, 

 and stellata, both before reading Trecul's paper and since, but without being able 

 to give the necessary time, of which some idea may be formed from Trecul's having 

 devoted more than a year to the study of Nuphar lutea alone, the result of which, so 

 far as the rhizome was concerned, brought him no further towards a definite con- 

 clusion than that " the structure of the stem, and of some other parts of the plant, 

 is what prevails in the greater number of plants that have one cotyledon," jMure 

 recently, however, after the study of Victoria, he expresses himself more positively, 

 and is " confirmed in his opinion of the analogy of structure that exists between 

 NympJt{sace(P and Monocotyledons." 



Commencing with our own analysis, we found that the rliizomes presented a cen- 

 tral medullary mass, surrounded by a tolerably well-defined zone of vascular bundles. 

 They differ from Exogens in wanting liber, wood-wedges, and medullary rays, and in 

 the confused arrangements of the vascular tissue ; and from Endogens in the vascular 

 zone surrounding a column of pith, in the arrangement of the vascular fascicles, and 

 in their"compositiou. Our conclusion was, that this structure was quite reducible 

 to a veiy low and deranged type of Exogenous stem, such as might be expected to 

 occur in an axis of which all the interuodes are crowded into the smallest possible 

 compass, and in a plant the habit and general arrangement of whose organs of support 

 and nutrition differ so widely from that of ordinary Exogens. In this opinion we 

 were strengthened by some peculiarities in the structure of the abbreviated rhizomes 

 of other Exogens, by the fact that vascular bundles often do form a confused plexus 

 at the nodes, and that their arrangement in these is hence not reducible to the Exo- 

 genous type which prevails in other parts of the same stem. The great deviations 

 from the normal type in Menispermaee^e, and very many other plants of less peculiar 

 habit than Nympka'-ace(S, further confirmed us in this opinion, no less than the fad 

 that there are no Endogenous rhizomes known to us with which those of Nymphce- 

 acecB can at all be compared. We may also re]jeat here what we have alluded to 

 under MeiiisprnnacPfO, that in our opinion a mere reduction of the Exogenous stem, 

 by the successive obliteration of its medullary rays and liber, and the confused arrange- 

 ment of its vascular bundles, by no means implies a transition to the Endogenous class- 

 AVe consider that there are other and far more important anatomical differences be- 

 tween these two great classes, and that, to establish an Endogenous affinity for the 

 rhizomes of such very anomalous plants as Nympliisacece, it is necessary to prove the 

 existence of some, at any rate, of the absolute characters of Endogeus, as the courses 

 of the vaScular bundles and their composition. 



Turning to Trecul's beautiful analysis of the rhizome of Nuphar lutca, we do not 

 find our opinion altered; these show the courses of the vascular bundles, and their 

 relations to the petioles, peduncles, and axis, with a precision that we failed to attain, 

 and we have full confidence in their accuracy; but there is nothing in these that appears 

 to US to establish an Endogenous affinity, and much that is seen in other Exogens. 



rienfrcy's careful observations on the rhizome of Victoria differ from Trcctd's on 

 iNtq-}har, and he treats the subject rather difl'erently. The rhizome of Victoria pre- 

 sents an almost solid axis of vascular bundles, not a zone of them. Its points of 

 affinity with Endogens licnfrey states to be: — 1. The apparently continuous develop- 

 ment of a terminal bud. To tliis we would object that the real nature of the growing 

 point is not likely to be easily demonstrable in an abbreviated axis of so many inter- 

 nodes, and that other manifestly Exogenous rhizomes present a similar appearance. 

 2. That the roots are all adventitious. This is perhaps the strongest point of any, but 

 its value in relation to the laws of germination in general cannot be said to be esta- 



