I90 BLECHNOID FERNS [ch. 



the base of the shorter and wider blade (see Christ, Farnkr. Fig. 66'j^. It is 

 but a step from this to the state of the sporophyll of the North American 

 Cainptosoriis rhizophylliis (L.) Link, or the Chinese C. sibiricus Rupr., with 

 their partially reticulate venation (Fig. 707,/^), but towards the margin and the 

 caudate tip of the blade the veins are free. In the broader reticulate region 

 the sori appear irregularly disposed, though still a reminiscence of the 

 IVoodwardm-type is seen in the soral fragments borne on the veins parallel 

 to the mid-rib. Towards the caudate tip the arrangement is simplified, passing 

 in C. sibiricus (Fig. 707, B) first into an arrangement reminiscent of B. 



B 

 Fig. 707. Irregular soral tracts of Camptosorus. A = C. rhizo- 

 phyllus (after Mettenius), showing reticulate venation, bearing 

 irregular soral tracts, often associated in opposite pairs as in 

 Phyllitis. B=C. sibiricus Rupr. Drawing from the narrowed 

 distal end of a blade, from China (Cowdray, 1920), Kew Her- 

 barium. Here there is a distinct approach to the condition seen 

 in var. Krebsii. 



punctulatum v. Krebsii, and finally it may merge into a simple Blechnoid 

 coenosorus. The most highly modified type of all is that of P. {Schaffneria) 

 nigripes (Fee) O. Ktze., where there is no mid-rib in thespathulate blade. The 

 venation is reticulate, especially near to the margin, and the disposition of 

 the soral tracts is irregular (Fig. 708). The broad scales still bear the glandular 

 tip as in Blechnum. All of these appear as results of further condensation of 

 leaf- form from that seen in the common Hart's Tongue. But yet they show in 

 their details traces of the Blechnoid origin, with B. punctulatwu v. Krebsii 

 as the index of that source. The reticulation may be held as secondary, 

 indicating such types as derivative: and with it habitually comes a less 

 regular disposition of the coenosoral fragments. These may frequently owe 

 their origin to innovation rather than to any direct disintegration of the 

 Blechnoid coenosorus. Nevertheless, the simpler and especially the distal 

 parts of the sporophylls, where the venation is open, point clearly to the 

 Blechnoid source for them all. 



