150 TRICHOMANES. 



Pr. S. l);uliuin, Pr. (Hymen. Hook, et Grcv.) Cumi»i<), PL Philip, n. 

 112). S. gracile, Pr. {Hymen. Hon/). S. demissura, ZV. (Hymen. 

 Sw.) S. sanguinolentum", Pr. (Hymen. Srv.) S. iinihilatum, Pr. 

 (Hymen. Sw. H. fumaiioides, Kauff. Kimze). S. axillare, Pr. (Hy- 

 n)en. Sir.) S. abietinum, Pr. (Hymen. Hook, et Grev.) 

 XIX. HvMENOGLOssuM, Pr. — H. cruentum, Pr. (Hymen. Cav.) 



SuBORD. III.— DAVALLIE.E. 



Sori globose or more or less elongated, situated at the apex 

 of a vein or veinlet, rarely on the back (below the apex). 

 Involucre superficial, inserted at the base of the sorus and 

 covering that sorus in the form of a scale, which is generally 

 half cup-shaped more or less elongated, sometimes scmicy- 

 lindrical, rarely ovate, or orbicular, or reniform, always free 

 at the apex sometimes also at the sides, but almost invaria- 

 bly fixed by a broad base, and at or near the margin of the 

 fronds or segments of the fronds ; varying much in texture, 

 from membranaceous to coriaceous. — Tu/tecl orcreepingYevns, 

 tropical or subtropical, rarely inhahiting temperate climates, 

 and chiejly the Old World, frequently with a stout scaly 

 horizontal caudex, of lohich the Davallia Canariensis, or 

 Hare's-foot Fern, is an example ; sometimes tufted. Fronds 

 simple or pinnatijid or variously and compoundly divided, 

 membranaceous or coriaceous. Veins simple or forked, not 

 in any instance, that J am aware of, anastomosing. 



Obs. Many anthors unite this gronj) or Suborder of Ferns with Dickso- 

 niece, from which tliey appear to me to be well distinguished by the invo- 

 lucre not having its origin beneath and all round the sorus, so as to form a 

 complete cup ; but, originating from the lower base of the sorus, it forms a 

 half-cup, the sides generally united with the frond, and free only at the 

 apex : still it must be confessed that in some cases (as will he seen by our 

 figures) when the sorus is at the narrow apex of a segment, that apex of the 

 segment is so united with the margins of the involucre that it ([uite resem- 

 bles the fructification of some Dicksoniccc, especially of a Loxsoma, or even 

 a Trichomanes : and, if the sides are free, the resemblance then becomes 

 great to Lindscea. In other cases, when the involucre is nearly orbicular, 

 or reniform, fixed by a more narrow base and free at the sides, and situated 

 at a distance from the margin, the aflSnity is with some Aspidiacece, espe- 

 cially with Nephrolcpis of Scliott. No two authors are agreed as to tlie 

 limits of this group, nor of the geneva which compose it : and no wonder, 

 seeing how gradually the genera seem to run one into another. To me the 

 genera appear to have been needles.sly multiplied, upon very insufficient 

 grounds, so that in many cases I cannot even adopt them as subgenera. 



