678 PROFESSOR F. O. BOWER ON 



the vein dichotomises. In (b) there are three veins ; evidently the right shank has 

 forked again. From this condition (c, d) illustrate how, by repeated right and left 

 dichotomies, a sympodial venation may be built up, with a prominent midrib. This 

 corresponds to what has been shown in Campbell's drawings for Angiopteris, 

 Marattia, and Dantea. It is an easy transition from fig. 10, d, to fig. 11, which shows 

 a young leaf of Angiopteris with incipient pinnation at the base. The venation of 

 its upper region is a simple elaboration of that in fig. 10, d. It shows on the right 

 hand a first basal pinna, and a second on the left is imperfectly indicated. The 

 basal lateral vein, essentially dichotomous, has developed sympodially, with a 

 marked midrib. The next vein on the left, though it supplies an evident lobe, or 

 imperfectly formed pinna, has a venation that is clearly dichotomous, the sympodial 

 development being hardly established. Upon these simple materials the scheme 

 of construction of the leaf in the genera Dansea, Marattia, and Angiopteris is 

 wholly based. In all it is essentially dichotomous, but with a scorpioid sympodial 

 character asserted early. 



In Kaidfussia the fundamental nature of the venation appears to be the same. 

 But it is obscured even in the juvenile leaves by reticulate anastomosis, which 

 may be held on ground of general comparison to be a character relatively recently 

 acquired. This is borne out by the first juvenile leaves,* in which anastomosis is 

 superposed upon a venation similar in its main branchings to that seen in Dansea 

 and Angiopteris. But the distal ends of the veins in Kaulfussia are connected 

 by curved loops. 



Certain features of the adult leaf of Angiopteris were described many years ago.t 

 It was found that the pinnae appear monopodially, in acropetal succession, and with 

 regular alternation on rhe two sides of the leaf. Their number is small, and the 

 " phyllopodium " terminates abruptly in a blunt cone,| which may sometimes still 

 be recognised in the mature leaf. An appearance is thus produced as though the 

 leaf were sympodial. Sometimes the last pinna takes an apparently terminal 

 position, but examination of the development shows that this is not its real position. 

 These features are important for comparison on the one hand with other Ferns, and 

 on the other with the Higher Plants. It would appear that in Angiopteris, after the 

 few monopodial pinnae have originated, the apical growth usual in Ferns ceases, as 

 it does in Cycads and Angiosperms. Nevertheless their arrangement accords with 

 the scorpioid sympodium usual in the earlier-formed pinnae of other Ferns. 



It was further concluded that the so-called " stipules " are basal growths origin- 

 ating below the pinnae, and not of pinna-nature. They are formed from those 

 marginal wings which may be more or less clearly traced throughout the length 

 of the leaves of Ferns. They appear to be of the same nature as the basal growths 

 in the Osmundaceae, but more massive. In Angiopteris there is a commissure 



* Campbell, liuit. Ann., t. xiii, pi. viii, fig. 36. t Bower, Phil. Trans., part ii, 1884, p. 479. 



\ L.c, figs. 16, 17. 



