SPINULOSE, OR COMMON WOOD-FERN. 



Still narrower, and perhaps a little longer yet. Successive 

 pinnae are gradually narrower, and less triangular in outline. 

 At about the fifth pair they begin to grow shorter as well 

 as narrower, and so rapidly decrease towards the acute and 

 slightly acuminate apex of the frond. The secondary rachises 

 are very narrowly winged. The pinnules are oblong or 

 oblong-ovate, sub-acute, and set on rather obliquely. They 

 are usually incisely lobed, but sometimes more deeply cut, 

 into oblong lobes which are spinulosely toothed at the apex, 

 and often somewhat so on the sides also. The veins are 

 always free. There are a midvein and from five to seven 

 veins in each lobe, the first vein being always on the supe- 

 rior side. These veins are either simple, or they bear a single 

 short veinlet on the upper side half-way between the midvein 

 and the margin. The sori are seated astride on the middle 

 of the vein, if it be truly simple, but if it be bent at an 

 angle as if trying to branch, the sorus is directed towards the 

 course the branch would take: — if the branch be actually 

 formed, the sorus is seated on it, either near the apex or 

 some distance below it according to the length of the branch. 

 I do not find any good distinction between this variety and 

 the next in the position of the sori, as indicated by Mr. 

 Davenport. The lower surface of the frond is smooth and 

 without glands, as is also the indusium, though most Euro- 

 pean authors note more or less frequently occurring excep- 

 tions to this rule. The spores are slightly reniform, and 

 minutely verrucose. 



