2i8 DIPTEROID FERNS [CH. 



definitely terrestrial. The two last-named are both more advanced types 

 than Cheiropleiiria. This comes out in C. tricuspis in the presence of scales 

 upon its fleshy rhizome, in its highly disintegrated stele and leaf-trace, its 

 ternate leaf-form, its more highly organised diplodesmic sporophyll, its 

 smaller but more specialised sporangia and lower spore-output. The features 

 that link it more especially to Cheiropleuria are the underlying general scheme 

 of construction, the diplodesmic sporophyll, and the absence of a perispore. 

 These also connect Christopteris with Platycerinm, notwithstanding its pecu- 

 liarities, which are no doubt related to habit. As illustrating the effect of this 

 the sporophyll of Platycerinm may be compared as regards outline with that 

 of the epiphytic Ophioglossicm palmatnm (Vol. II, Fig. 343). No one would 

 suggest any near phyletic relation between these bizarre epiphytes : but such 

 similarity as they show gives one of the most striking examples of homo- 

 plastic adaptation to like conditions. 



Copeland (Perkins, Fmgmenfa, 1905, p. 188) founded the genus Christopteris on C. sagiita 

 (Christ) Copeland, a species already described by Christ as Polypodium sagitta {Bull. 

 Herb. Boiss. p. 199, 1898). This is a Fern with creeping rhizome bearing bristle-like 

 paleae. The sterile leaf is long-stalked with a broad triangular blade, and venatio anaxeti. 

 The fertile leaves are narrow and Acrostichoid. Later {Philipp. Journ. Botany., Vol. xii, 

 No. 6, 1917) Copeland suggested the inclusion oi Leptochilus tricuspis (Hk.) C. Chr. and 

 L. -uarians (Mett.) Fournier in his new genus ; he finds confirmation in the fact that they 

 also are diplodesmic, and that they all have paraphyses, usually simple and small, as in 

 C. tricuspis : also that their paleae, though peltate at the base, are drawn out at the apex 

 into long bristles. Later there were added C. cantonieiisis Christ from Canton, C. Cope- 

 landi Christ from the Philippines, and C. Eberhardtii Christ from Annam. The genus 

 thus constituted has a rather wide distribution, though clearly centred in the Malayan 

 region. One species is Himalayan, others are from Siam, South China, the Philippines, and 

 from New Caledonia. This Copeland regards as indicating antiquity : and he refers them 

 to the ancient Matonioid-Dipteroid stock, along lines of comparison based upon those of 

 my Studies VI, Jan. 1917. 



It may be that as detailed knowledge increases other Ferns of "Acrostichoid" or " Poly- 

 podioid" character may ultimately find their place with those already in Christopteris. 

 They may either be new species discovered in that prolific Eastern region, or others already 

 assigned, as Leptochilus varians has been, to some other affinity. It is interesting mean- 

 while to note that Frau Schumann {I.e. p. 250) has already placed L. varians in close 

 relation with L. tricuspis., both being without perispore. 



Neocheiropteris Christ 



The Fern named Neocheiropteris palmatopedata (Bak.) Christ is a native of 

 Yunnan. It was originally referred to Polypodiiun by Baker, but was given 

 generic rank by Christ. It has a rather thick fleshy hypogean rhizome, 

 bearing ovate scales: the leaves are solitary, with a long petiole bearing a 

 pedatifid blade, deeply lobed with the apparently middle lobe erect, as in 

 Matonia, while the lateral lobes are patent and pedate (Fig. 727). The well- 



