CHARACTERS OF TRIBES AND GENERA. 
“Synopsis” of the above work, the number is reduced to 
. seventy. With a few exceptions they are stemless, gene- 
. rally cxspitose, with smooth glossy fronds, a few only 
being slightly pilose or furnished with glands. The 
greater number have free venation, but anastomose vena- 
tion characterises Woodwardia and its allies. 
170.—BrzcnwuM, Linn., in part (1754). 
Hook. Sp. Fil. 
Vernation fasciculate, cespitose, often stoloniferous, or 
solitary erect, sub-arborescent. Fronds simple, pinnatifid 
or pinnate, from a few inches to 4 to 6 feet high ; pinne 
adherent or rarely articulated with the rachis. Veins 
forked ; the sterile venules free, or their apices thickened 
and forming a cartilaginous margin; the veins of the ` 
fertile pinne combined near their base by a transverse, 
continuous, sporangiferous receptacle, constituting a linear, 
_ costal, or rarely extra-costal sorüs. IJndusiwm linear, pues 
Type. Blechnum occidentale, Linn. ; 
Illust. Hook. and Bauer, Gen. Fil., t. 54 B. ; Moore Ind, 
p. 11 B.; J. Sm. Ferns, Brit. and For., fig. 100 ; Hook. 
- Syn. Fil, t. 4, fig. 34. | 
Oss.—In the " Species Filicum " forty species of Blech. 
. ^um are described, but in the * Synopsis Filicum" they 
 &re reduced to eighteen, 
2 Great confusion exists in the synonymy of this genus. 
with that of Lomaria, the most obvious distinguishing cha- 
acter being in the fertile fronds of the latter being con- 
. tracted, but I must admit that this distinction is not always. 
definite, it being difficult to determine to which genus 
. certain intermediate forms belong, and, to make the matter 
: | Worse, Presl characterises the species of Blechnum under 
