ZOOLOGY AND BOTANY. MICROSCOPY. ETC. 573 



the estublishment of a collective species so large as to be inadmissible in 

 the present state of descriptive botany. 



Affinity of Neurocallis.* — H. Christ, in a supplementary note 

 corrects an error made in his fifth paper on the ferns of Costa Rica. A 

 new species, Pteris macrodktya, was there described from fragments of a 

 sterile frond of what is now shown to l)e Neurocallis. It is interesting 

 that Baker made an analogous mistake in describing a soriferous frond of 

 Neurocallis as Pteris dominicensis, an error which Jeuman set right. The 

 outcome of the present correction is that the distribution of Neurocallis, 

 believed hitherto to be confined to the West Indies, is now extended to 

 Central America, and that an addition is made to the species common to the 

 Antilles and Costa Rica. The genus Neurocallis is of uncertain affinity. 

 Placed by some writers in Acrostichum and doubtfully near A. aureiini, 

 its irregular network of veins is more like that of the Pteris Haenlceana 

 group than the small regular network of A. aureum. Its texture is 

 herbaceous, not coriaceous ; the sori linear, marginal, leaving free a wide 

 costal band ; edge of soriferous pinn^ narrowly reflexed like an 

 indusium. Just as StenochlcRiia is regarded as a derivative of Asplenium, 

 so Neurocallis may prove to be an acrostichoid species of Pteris. At 

 present it should be left an independent genus. 



Dimorphic Fronds of Stenochlgena.t — H. Christ discusses the 

 biological and systematic meaning of dimorphism and malformation in 

 epiphytic ferns, especially StenochUena. Climbing ferns, which have to 

 grow up to a height of some 170 ft. in order to get the benefit of the 

 sunshine, require the most ingenious contrivances to maintain their 

 existence. Such are the humus-storing nest-leaves of Drynaria and 

 Poll/podium biforme, the sap-storing tubers of the stolons of Nephrolepis, 

 the so-called water-leaves of Aspleniwn obtusifolium, leaves of analogous 

 function in Pteris, and above all the marvellously multiplex lower leaves 

 of Stenochlmia. This latter plant roots in the ground and sends up a 

 branched rope-Hke climbing stem to a height of 60 or 100 ft. or more, 

 and bears the ordinary assimilatory and soriferous fronds at the top of 

 the tree by which it has climbed. But down below it is clad with a 

 dense foUage of deep green tender finely divided leaves of utterly 

 different appearance — so different in fact that they have been referred 

 by the older authors to other genera, namely to Scolopendrium by Bory, 

 to Davallia by Hooker, to a special genus Teratophyllum by Mettenius, 

 to Diplora and Triphlehium by Baker. Karsten, though giving us an 

 excellent account of them and a good interpretation of their functions, 

 still held to their inclusion in the pseudogenus Teratophyllum. One of 

 the first to claim them as appendages of SteiiochUena was Bishop Hose. 

 Copeland's Asplenium epiphyticum is without doubt a Stenochlmna. 

 Christ describes the manifold variety of form of these lower leaves and 

 points out their more primitive Hymenophyllaceous structure as compared 

 with the upper assimilatory leaves, and holds that their function is to 

 absorb moisture and aid in the nutrition of the plant. There is, he 

 believes, an atavism about them ; they are an ancient type of leaf 



* Bull. Herb. Boissier, vii. (1907) pp. 585-6. 



t Verb. Schweiz. Natur. Ges., St. Galleu, 1906, pp. 178-88 (12 pis.). 



