SPECIES AND VARIETIES OF BRITISH FERNS. 61 
4. A. viride, Hudson. —Fronds linear, pinnate, rachis green 
above. Plate XIII. fig. 4. 
5. A. Trichomanes, Linnaeus. —Fronds linear, pinnate, ra¬ 
chis black throughout. Plate XIII. fig. 5. 
mr. incisum.—Pinnae deeply lobed. 
mr. cristatum.—Fronds tasselled at the end. 
6. A. marinum, Linnaeus.- —Fronds pinnate, rachis winged. 
Plate XIY. fig. 1. 
7. A. fontanum, It. Brown. — Fronds bipinnate, narrow 
lanceolate, rachis winged, smooth. Plate XIII. 
fig. 2 . 
8. A. lanceolatum, Hudson. — Fronds bipinnate, broad 
lanceolate, rachis wingless, scaly. Plate XII. fig. 1. 
mr. mierodon.—Pinnae only lobed or subpinnate at the 
base, wavy. 
9. A. Adiantum-nigrum, Linnaeus. —Frond bipinnate, tri¬ 
angular ; segments wedge-oblong. Plate XII. fig. 2. 
mr. acutum. — Fronds tripinnate, triangular, much 
acuminate ; segments linear. Plate XXII. fig. 2. 
Genus 8. CETERACH, Willdenow. 
1. C. officinarum, Willdenow. —The only British species. 
Plate I. fig. 1. 
