ON THE GERMINATION OF CHARA. 307 



thus makes it a part of the pro-embryo. It is not a part of the pro- 

 embryo, but a part of the primary root, which iu its formation, and 

 frequently, too, in its first growth, is a shoot of equal morphological 

 value with the pro -embryo. The first secondary shoots of this node are 

 the lateral rootlets springing from the base of the root ; the ramifi- 

 cations of the root-node and first node of the stem are the secondary 

 shoots of the pro-embryo. The first node differs from all succeeding 

 ones in this, that it is split by the halving- wall into two equal forks, 

 which, it is true, eventually assume very different characters. It is 

 conceivable that species or individuals exist in which the two forks 

 remain equal in their development, and two similar pro-embryos grow 

 out of the first node without any primary -root ; but such a case, it is 

 true, has not hitherto been observed. 



Premising the structure and order of development of the shoots to 

 be understood, we may recapitulate the foregoing observations on the 

 normal morphological phenomena in the sense that the Chara plant is 

 built up of three successive grades of unequal shoots. The first arises 

 in the slightly elongating oospore, and consists of the basal cell and 

 the first node. The latter divides into two originally equal branches 

 of the same morphological status. These develop unequally as the 

 primary root and principal pro-embryo ; from the latter proceeds a 

 shoot of the third grade, forming the first stem. 



From the nature of the thing the first of these shoots can only be 

 present in the singular number, for it undergoes no organisation beyond 

 that described. The principal pro-embryo gives birth in its two 

 nodes, on the one hand, to lateral rootlets, and, on the other hand, to 

 rudimentary leaves as integral parts of its structure, not as equal rami- 

 fications. The primary root branches into equal forks, not only at its 

 base, but also in its successive joints. The primary stem, unlimited in 

 longitudinal growth, and the continual repetition of the successive for- 

 mation of internodes and nodes, is also typically unlimited in its parity 

 of branching, for in each whorl of leaves there is the rudiment of a 

 normal branch in the basal node of the first leaf, or of the first and 

 second leaves, which branches may grow out and ramify in the same 

 unlimited manner. But the first stem, proceeding direct from the 

 third node of the pro-embryo, suffices in itself to form a perfect and 

 complete plant, inasmuch as it has the power to form sexual organs in 

 its leaf-whorls. This may be seen even in germinating plants of the 

 commonly very intricately branched Tolypella glomerata ; and in Chara 

 crinita^ as already mentioned, the shoot in question frequently bears 

 oogonia in its first whorl of leaves. 



The arrangement and order of succession of the shoots described 

 are termed typical or normal, because necessary to the formation of a 

 perfect plant, because the same sequence is constant in every indivi- 

 dual, and each limb or joint is invariably developed in the same mor- 

 phological position, and from a cell that may be predetermined, and, 

 finally, because they not only theoretically, but often actually, build 

 up the plant alone, without the addition of others. But the actual 

 formation of the plant need not be limited altogether to the normal 

 members, for they may be supplemented by accessory or adventitious 

 shoots, which, regarded in themselves, may be referred to this or that 

 category, but differ from the normal in that they may remain unde- 



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