XXXIX] NOTHOLAENA 91 



(12), and in A'', sinnata (Lag.) Klf. (16-32), suggest that these species are 

 advanced in this feature, while the numbers in A^. affiiiis (Mett.) Moore 

 (16-64) present a specially high degree of variability (see Thompson, Trans. 

 Roy. Soc. Edin. Vol. Lir, Pt. 11, p. 386). 



Since in certain species of Notholaena the relatively large and even 

 solitary sporangia appear very close to the leaf-margin when mature, a 

 particular interest attaches to the question of the exact point of their origin 

 relatively to the marginal cells. The excellent figure of Schkuhr [Farnkrdiiter 

 Tab. 99) shows how in N. tricJwinanoidcs the mature sporangia appear as 

 though marginal, and the sori apparently confluent. It would therefore 

 seem to be a suitable species for testing the question. Sections of the young 



Fig. 644. Notholaena trichomanoides (L.) R. Br., showing the close relation of the young sporangia 

 to the leaf-margin, j = sporangia : ;^ = hair: /« = marginal cell. {A, B x 200. Cxioo.) 



pinnae show clearly that the sporangia are intra-marginal: they arise from 

 segments back from the actual marginal series, though in near proximity to 

 it. Moreover the first cleavage of the sporangial cell is by a wall that 

 impinges upon the basal wall (Vol. II, Fig. 455). These facts suggest that 

 the sporangium itself is of a relatively primitive type, with its first segmenta- 

 tion after the manner of the Schizaeaceae: but while in the latter the 

 sporangia actually originate from the marginal cells, here they are super- 

 ficial, though springing from some of the latest segments cut off from the 

 marginal series (Fig. 644). 



The prothallus bears glandular hairs of exactly the same nature as those 

 so profusely present on the young leaves of the sporophyte (Vol. I, Fig. 

 186). 



