132 



NATUIiAL mSTORY OF PLANTS. 



bearing on its inner face the two cells, adnate for their whole 

 length, and each dehiscing by a longitudinal cleft.' The carpels, 

 also indefinite, consist each of a one-celled ovary, 

 surmounted by a horn-shaped style, bent outwards at 

 the tip." The whole of the inner face of the ovary 

 and style is traversed by a longitudinal groove, of 

 which the everted edges are covered above with 

 numerous stigmatic papilla?. In the inner angle of 

 the ovary is seen a parietal placenta bearing two de- 

 scending anatropous ovules, witli the micropyle looking 

 upwards and outwards.^ The fruit consists of a large 

 number of finally dry carpels' inserted on the now woody 

 axis. Each opens when ripe along the dorsal suture (fig. 168),* 

 to free one or two seeds which remain for a variable time sus- 

 pended to a slender filament (fig. 109)." Each seed has three 

 coats ■/ the outermost is quite fieshy ; the middle hard and testa- 



' The pollen of M. gran<liJlora L. consists of 

 grains of the shape of a grain of corn, somewhat 

 acute at each end, and with a large longitndinal 

 fold due to the inflexion of the outer coat. H. 

 ^loiiL has already pointed out that it has the same 

 form as in most Monocotyledons {Ann. Sc. Nat., 

 S('r. 2, iii. 221). In contact with water the form 

 changes, so that the fold disa])pcar8, the length 

 is diminished, and the ends are rounded. The 

 exterior is covered with projecting granulations of 

 a fatty consistency, and the superficial and deep 

 parts of the grain present a marked contrast in 

 colour. The centre is darkest, and finely granular. 

 M. macrophylla Miciix., has similar jwUen 

 grains, hut more elongated and fusiform. 



- The style varies greatly in form and size 

 from the short somewhat dilated horn of M. 

 grandijlora L., or the slightly hooked suhulatc 

 point of M. Yulan Desk., to the revolute and 

 almost plumose style of M. glauca L., in which 

 last the j)apilla- of the margins of the internal 

 groove are not simple, but branched. 



* When adult, tliey become more or less oblique, 

 and sometimes even horizontal. At the same 

 time, the micropyle inclines somewhat to the 

 lattrul walls of the cell, and the rai)hos approach 

 one another on the middle line. They have two 

 coats. There are sometimes three ovides in the 

 ovary of M. Yultin 1)i:sf. and vtacrophylla 

 MlCllX. ; the third is then suiM.rior and nearly 

 median. 



* In several sitecics they long imisschs a lleshy 

 consistency, and a pinkish or yellowinli tint, re- 

 culling that of certain surculent |)ericar|iH. In 

 ■onio, tlio wmxly endocarp separates from tin- 



thicker and less consistent mesocarp after de- 

 hiscence. 



•'' Dehiscence in most species takes place simply 

 by a longitudhial cleft, of which the borders 

 separate to form two lateral panels. In some 

 others, as M. macrophifUa Micnx., besides the 

 two panels, we perceive the dorsal rib, womly, and 

 like a long subulate filament, only attached to 

 the receptacle by its base, and free from all ad- 

 hesion to the lateral walls. 



^ This filament consists of trachea*, which are 

 continued into the raphe of the seed; the turns 

 of their spirals separate as the seed di-scends. 



^ The curious organization of these seeds, with 

 an outer fleshy coat, which Linn.kus called an aril, 

 has been a source of long discussions to the bota- 

 nists ofour times (Mii:KS,Co«/ri6.,i.U>2, 17 1,211 ; 

 IIooKKU F. k TnoMs., Fl. IihJ., i. 77; A. Okay, 

 in Jlook. Jouni., vii. 2 13). Tiio origin of the 

 outer coat has been attributed to various organs, 

 some making it a special sac emanating from the 

 placenta, and finally enveloping the whole seed ; 

 while others consider it one of the pnijwr seed 

 coats, singularly modified al\er a certain age. 

 This la.st interpret^ilion alone appears stitisfactory 

 to ns, as will bo seen in the following extnut 

 fnnn the special article we recently devototl to 

 this subject {Complin Jtrndit.t, Ixvi. 7lH); Adiin- 

 Konia, viii. Ifill) — " Tlie so nmch dis|)uted origin 

 of the fleshy coat of the seeil of Mugnulia is de- 

 monstrated both l>y Wm develtipmcnt and by iUt 

 histologicid structure. It in formed by theliyinr- 

 trophied cells of the priinine, ricli firitl in starch 

 an(l afterwanls in oily matter. MoriMVer, its 

 thickness is traversed by the tracheal bundles of 



