XLVlIlJ 



PROSAPTIA— TAENITIS 



255 



(Fig. 588, C-H) : the peculiar twin bristles on the leaves, the clathrate scales 

 of the rhizome, and the vascular anatomy also coincide. Even the superficial 

 origin of the sorus, though it arises very close to the margin; the method 

 of its overgrowth by tissue that is not of the nature of an indusium in the 

 sense of Davallia; the details of the sporangia and spores, all point to 

 Polypodium obliqiiatuni. The difficulty lies in the near proximity of the sorus 

 oi Prosaptia in point of development to the margin, which results in a close 

 imitation of Davallia. The whole story, which runs curiously parallel to that 

 of Cystopteris in comparison with Diyopteris, shows that Prosaptia is not a 

 Davallioid Tern. It is one of the superficial series in which the sorus, with 

 special modifications, has approached secondarily to a marginal position. 

 (For the systematic treatment of Prosaptia see Van Rosenburgh, Malayan 

 Ferns, 1909, pp. 567, 613.) 



Fig. 750. a = Polypodium obliquattun, portion of a young fertile leaf, seen from below. 

 The sori are hidden in long grooves, with only a narrow opening. b = Prosaptia sp. 

 from Sumatra. Part of a leaf with young sorus, seen from below. It is clear that the 

 lower part of the soral sheath belongs to the lower leaf-surface. Note the twin bristles 

 on the leaf-surface of both. (After Von Goebel.) 



Taenitis Willdenow 



The Taenitidinae, as grouped by Diels (E. & P. I, 4, p. 302), are palpably 

 an unnatural association, from which Heteropteris Fee (= Paltoniuvi Presl), 

 Hyvienolepis Kaulfuss, and Christopteiis Copeland, may be detached on the 

 ground of their venation, as well as on other features (see Chapter XLV). 

 Of the remainder the leading type is Taenitis, a genus which affords one of 

 the most open problems of comparison. This also has been recently treated 

 by Von Goebel, but with indecisive results. It may still be held as a "genus 

 incertae sedis." 



The genus is characteristically Malayan. The synonymy of its best 

 known and for long its only species, Taenitis blechnoidcs (Willd.) Sw., 

 occupies nearly a page of Christensen's Index. The rhizome of this ground- 

 growing Fern bears hairs, which are enlarged at the base into a cellular 



