

CLASS IV. — ENDOGENS. 



Mono< - i$. Oen.il. 1788 ; Dei/. Mtm. Tiat. I 



L82I Imphibrya, . 



[laving now passed in review the absolutelj sexless plants, called Thallo- 

 . and all that class which, under the title of A.crog< as, compreh< nd« 

 numerous race among whom the existence of a double Bex is conjectured 

 to exist, ami having, moreover, disposed of the curious Rhizogens, winch, 

 a fungal mode of growth join a complet iol apparatus, we pass to 



End( or Monocol 5 Ledons. 



Here we find avast multitude of sp rith extremely diversified habits, 



among whom occurs every attribute supposed to be connected with tl. 

 perfeci structure. Leaves and stems are distinctly separated ; spiraH 

 breathing-pores, and air in a condition that admits of no furthei com- 



plication ; and we find in the great majority everything which constitutes as 

 elaborate an arrangement of parts as >\e have any knowledge of in the 

 table kingdom. 



This greal class bears the name <■!' Eudogens, in consequence of its 

 new woody matter being constantly developed in the first instance towai 

 the interior of the trunk, only curving outwards in it- course downwards. 

 That palm-trees grow in this way was known so long since as the time 

 Theophrastus, who distinctly speaks of the differences between c- 1 1 . 1 ■ _ • 

 ami t oogenous wood. 4 But that this peculiarity is also ext< uded t>> a con- 

 siderable part of tin' vegetable kingdom i- a modern fact, the discovery 

 which we owe t" tin- French naturalists Daubentonand Desfontaincs. The 

 path being thus opened, the inquiry lias subsequently, ami mere particularly 

 df lat.' \car-. been much extended, and tin' result is tin.' conviction that .ill 

 those numerous races to which Jussieu applied the name of Monocotyledon 

 agree essentially in this manner t>\' growth. We may I ike the palm-tn 

 typical of the endogenous structure. In the beginning the embrj 

 palm consists of a cellular ma-- of a cylindrical form, very small ami not at all 

 divided. As booh as germination commences a certain number "t cord* 

 ligneous fibre begin t" appear in the radicle, deriving their origin fn 

 plumule. Shortly afterwards, as soon as the rudimentary lea 

 plumule begin to lengthen, 3piral ami dotted vessels appear in t! in 



connection with the ligneous cords ; the latter increase in quantity 

 plant advances in growth, shooting through the cellular tissue, ind 

 parallel with the outside of the root. At the same time the cellulai I 

 ineiea-es in diameter to make I-.., ,m for the ligneous cords 



as tin-, are olsO ealle,l •. At la-t .i young hat' i- d( Veloped with a 



able number of such cords in connection with it- base, and, 



aU round the plumule, these cords ar nsequentlj conni 3 with 



the centre which that base surrounds. Within tin- ■ dly 



unfolds, the cellular tissue increasing horizontal!) at t ; ■ the 



ligneous cords, however, soon cease t,. maintain anyl 



*'Ej;ii Si ri-.r ur.r-a,. rk ui, wjjjr. 

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