XLViii] DEPARIA 259 



This is in essential accord with Dennstaedtia: but a difference appears in 

 the fact that instead of the marginal sorus turning downwards with age, 

 here it is directed definitely upwards. The origin of the superficial sori has 

 been found by Thompson to be essentially the same, with a like relation 

 to a vein-ending; a fact that bears upon the interpretation of their unusual 

 position. If Deparia be adopted as a good genus, it is clearly related to 

 Dennstaedtia through D. prolifera. The divergent peculiarities of the leaf of 

 D. Moorei may be interpreted in relation to its shade-habit. A broader leaf- 

 expanse and reticulate venation are signs of specialised advance; they are 



B. C 



Fig- 753- Young sori of jJeparia l\Ioorei Hook., showing their marginal origin. In A the 

 wedge-shaped cell marks the centre of the receptacle, with the upper and lower indusial 

 lips arising superficially. B shows the same more advanced. C is a sorus almost mature, of 

 mixed type, and definitely turned upwards. The figures have all the natural orientation. 

 Highly magnified. (After J. M^L. Thompson.) 



seen also in the shade-loving Hypoderris among the VVoodsioid Ferns, in 

 Onoclca as against Mattcuccia, and in Christensenia among the Marattiaceae. 

 Similarly D. Moorei would appear to be a condensed shade-form of Deparia. 

 With that condensation it may be held that the occasionally included veins, 

 stopping short of the margin which they all reach in the originally open 

 venation, offer a physiological opportunity for the formation of sori here 

 not marginal, but appearing in an anomalous position on the upper surface. 

 An analogy, though not an exact one, of transfer of sori to the upper surface 

 is seen in Polystichum anomalum (Vol. I, p. 225). In neither case should any 

 far-reaching phyletic or systematic weight be attached to the anomaly. 

 Deparia, including D. Moorei, should therefore resume its natural place as 

 a substantive eenus derivative from the Dennstaedtioid Ferns. 



