330 Dr. G. Ogilvie on the Vascular and Woody Tissues of Ferns. 
to the external characters of the rhizomes, as explained in my 
former communication on this subject (Ann. Nat. Hist. Dec. 
1859). 
Rootstock a stoloniferous rhizome. 
Polypodium vulgare. Adiantum Capillus Veneris. 
Dryopteris. Hymenophyllum Tunbridgense. 
Phegopteris. —— Wilsoni. 
Lastrea Thelypteris. 
Trichomanes radicans. 
Pteris aquilina. 
Rootstock a dichotomous caudex. 
Polypodium alpestre. Asplenium viride. 
Polystichum Lonchitis. trichomanes. 
Lastrea Oreopteris. —— Ruta muraria. 
rigida. septentrionale. 
Cystopteris fragilis *. Woodsia Ilvensis. 
Athyrium Filix foemina. Allosorus crispus. 
fontanum. Scolopendrium vulgare. 
Asplenium Adiantum nigrum. Ceterach officinarum. 
lanceolatum. Blechnum boreale. 
—— marinum. Osmunda regalis. 
Rootstock a right caudex (extending by a single terminal bud). 
Lastrea cristata. 
Botrychium Lunaria. 
Ophioglossum vulgatum. 
Polystichum aculeatum. 
Lastrea Filix mas. 
—— dilatata. 
EXPLANATION OF THE PLATES. 
PLATE V. 
Fig. 1. Cross section of the rhizome of Osmunda regalis, showing the 
brown cortical substance and the pale tissue within, surrounding 
the central vascular cylinder with its cellular pitb, and a cambium- 
layer only on its exterior: @ a, origins of the petioles; 5 6, root- 
lets. (The outer tissue has been partially pared away, to fit the 
specimen into the section instrument.) 
Fig. 2. Cross section of a petiole near the base, showing the cut extremities 
of the longitudinal filaments and of the crescentic fasciculus and 
dark band. The asterisk in this and the other sections of petioles 
marks the side next the rhizome—that which is uppermost when 
the frond is laid on its back. - 
Fig. 3. The central vascular cylinder of the rhizome of O. regalis dissected 
out, showing the imbricated fasciculi going to the petioles. 
Fig. 4. A portion of the netted cylinder of Lastrea dilatata opened out, 
showing the origin of the petiolar fasciculi. 
Fig. 5. Cross section of the rhizome of Blechnum boreale, showing the 
great development of dark tissue in this stem. The outer series 
of fasciculi (in pairs), a aa, belong to the origins of the petioles ; 
* The other British forms of Cystopteris are questionable species ; but 
if Mr. Newman is correct in assigning to C. montana a “ stoloniferous 
rhizome” (History of British Ferns, p. 97), this may perhaps. be a good 
species. 
