GYMNOCAEPIUM EOBERTIANDM. 69 



the second in little else than magnitude. In the figure at page 

 68, I have taken great pains to give a faithful representation of 

 some young fronds : I divided the stipes of each, on account of 

 its inconvenient length, and laying them on the block before 

 me, made an accurate copy, both as regards size and figure. 

 The stipes is much stouter and more succulent than that of G. 

 Dryopteris, and I think also more scaly ; it is of the same dull 

 green as the frond, whereas the stipes of G. Dryopteris is fre- 

 quently purple or blackish, and has a more wiry appearance. 

 The frond attains its full development in Juty, and matures its 

 seed in August. The form of the expanded frond is nearly tri- 

 angular, the base being shorter than the sides, and altogether 

 not unlike that of the common brakes : the pinnae are opposite ; 

 the first pair always have a short naked stalk ; the second pair 

 frequently have a similar stalk, but not invariably, and the 

 naked stalk of the first pair of pmnee is always shorter and 

 rather more slender than the maiti rachis between the first and 

 second pair, whereas in G. Dryopteris the three are of nearly 

 equal length and thickness : the pinnse are pinnate, the pin- 

 nules deeply pinnatifid : all parts of the frond are covered with 

 the "subtile tomentum" described by Hoffmann: this consists 

 of a number of minute stalked glands. The bend, so observa- 

 ble in G. Dryopteris at the point of union of its three branches, 

 is much less marked in G. Eobertianum. The lateral veins of 

 the lobes of the pinnules are undivided, and the capsules are 

 borne in circular clusters near the termination of each, as in 

 both the preceding species. These clusters become confluent 

 in the autumn, and form a continuous marginal series. 



I have made this description comparative rather than posi- 

 tive, on account of the confusion which has long subsisted be- 

 tween two closely allied species. 



This fern grows freely in the ordinary soil of gardens, but 

 seems peculiarly to enjoy a plentiful admixture of limestone 

 broken small : it suffers no injury from full exposm'e to the 

 sun. When cultivated in the greenhouse, it should be jjlanted 



