410 



N VMPH.EACE.E. 



[Hypogynous Exogens. 



It seems, however, desirable to state, in this place, what the reasons are which , hare 

 Se wiS avey confused distribution of fibrovascular bundles among it not at all 

 accoramgw ^ uucl ° , , j^es of fibres are there placed in a con- 



to ltf n «toSKiC e ^r2e importance of so-*, «. leost, of these con- 

 aider,' ions ; P „« l'd„ »"« .hint that the, quite dispose of the quest™ J- to»h«. j, m . 



Fmlncrens as Schleiden first pointed out, and has no resemblance to that of -^gens. 

 ^teafiett derled from internal structure is therefore more in favour of Water- 

 hies bS Endogens than Exogens. The true ground for considering then i Exo- 

 5ens isSainlv confined to the two-lobed embryo. It seems to have been forgotten 

 SwlenTown and Brongniart proved Richard's cotyledon to be nothing , more -than 

 he annuotic sac, they did not also prove, as a necessary consequence, that the so-called 

 SumuTof Sard was a dicotyledonous embryo. It may be monocotyledonous, 

 not^thstandin' its vitellus. Certainly its two lobes are very like those of Exogens ; 

 Eut I toTthat nVymphcea alba the lobes are not suddenly contracted at their base 

 Uke true cotyledons, (no? are they in Nelumbium,) and, moreover that the plumula is, 

 ntthTplan Placed in an oblique direction with respect to the lobes • so that, in fact, 

 L embryo of NySpl-a is much like a modification of such monocotyledonous embryos 

 as thL of Aponogeton, Cymodocea, and Posidoma.-See Ann. Sc. n.s. m(1. 

 Sdeed, I perceive° no re Jon why it should not be regarded as having , one spht 

 coSon rather than two distinct ones. The principal mass of the nucleus m the 

 Leas o r6rchids appears from the researches of Professor Link to be an analogous 

 Tasf In these plaL the nucleus is a spheroidal cotyledon, from whose surface Jhe 

 radicle and plumule respectively protrude. We have only to imagine it elevated on each 

 side and we P should have the twodobed body of this Order. For the present, however, 

 I am not prepared to disturb existing arrangements ; though I much suspect tfia 



will be done by some other Botanist. Indeed Jtt. Ail. uiong 

 niart has lately declared that the position of Waterhlies 

 appears to him very AoubtiuL— Enumeration xxv. De Lan- 

 doUe assigns as a further reason for considering Waterhlies 

 to be Dicotyledons, that they are lactescent, a property not 

 known in Monocotyledons. But in this he is mistaken ; Lim- 

 nocharis, a genus belonging to Butomads is lactescent 

 Finally, Mr. Hassal appeals to the condition of the pollen ol 

 Waterhlies, which he thinks proves them to be undoubted 

 Monocotyledons. The pollen grain of Nvmphsea is de- 

 scribed by this observer as being oval, hispid, with a tur- 

 row down one side, and emitting a single pollen tube, which 

 marks he regards as characteristic of Eudogens. 



The germination of Nymphtea alba is not exactly either 

 exogenous or endogenous. The radicle is clearly endorhizal, 

 as in the latter; but the cotyledons lengthen their bases to 

 allow the plumule to escape, just as in an acorn ; and this u 

 perhaps one of the strongest arguments in favour of the lobes 

 of the embryo being really cotyledons. 



Supposing this Order to be exogenous and dicotyledonous, 

 its immediate affinity will be with Poppy worts, with some 

 genera of which it agrees in the very compound nature 01 

 the fruit, from the apex of which the sessile stigmas radiate, 

 in the presence of narcotic principles and a milky secretion, 

 and in the great breadth of the placentae. Waterhlies are 

 F,g. cclxxxx ii. bu. ana ^.^ ^ to Mag noliads, with which they agree 



Fig. CCLXXXVII. bis— Germination of Nymphsa alba. 



