CH. XLIV] 



BLECHNUM 



171 



§Eu-Blechnum 

 Such conditions as those just described lead naturally to the state charac- 

 teristic oi Eu-BlediniLin, as it is seen in B. brasiliense Desv., or B. occidentalc L. 

 (Fig. 693). These are large sub-dendroid species, with pinnate leaves, bearing 

 on their bases and on the stem and terminal bud dark scales, together with 



Fi(T. 693. Blechmiin (L.) \^EH-Blechnum\ A-C^B. occidentale L. ^=part of a leaf. B, C = dia- 

 grams of the venation, i? of a sterile, C of a fertile pinna. D-E = B. voiuhile Kaulf. Z) = part of a 

 leaf, ^ = part of a pinna with venation and sori. (i?, C after Mettenius, the rest after Diels.) From 

 Natiirl. Pflanzcnfam. 



mucilaginous hairs (Vol. I, p. 198). Their leaves are all alike, and their 

 pinnae broad. The fertile pinnae bear coenosori of the same type as in 

 B. spicant, seated close to the mid-rib (Fig. 693, A). In their development 

 the wings of the fertile pinna arise in the same way as the sterile, by the 

 usual marginal segmentation (Fig. 692, 12, a). The sorus does not make 

 its appearance until the wing has attained considerable size: it originates 

 as a rather massive upgrowth at some distance from the actual margin, 



