BOTANY. 65' 



high, Avhich give a peculiar character to the landscape. The thcca of ferns 

 has been looked upon as a modified leaf, having the same gyrate or circinate 

 development as the frond. Leaves have occasionally been produced in place 

 of theci^. Ferns having the theca3 on the back of the frond, and furnished 

 with an elastic ring or band, are called dorsiferous and annulate ; while those 

 having no thecal ring are exannulate. 



Few of the ferns are used medicinally. They are in general demulcent 

 and astringent. Some yield food. The rhizome of Lastrea Filix mas, 

 Male-shield-fern, has been used as a vermifuge, especially in cases of 

 tape-worm. It contains starch, gum, saccharine matter, tannin, green 

 fixed oil, and resin. Its properties are ascribed to the fixed oil. The 

 rhizome has been used for tanning, and its ashes contain much carbonate 

 of potash. The syrup called capillaire, and certain pectoral mixtures, are 

 prepared from Adlantum pedatuni and A. Capillus Veneris. The rhizome 

 of Pteris esculenta is used as food in Australia, and that of Marattia alata 

 in the Sandwich Islands. Many other species of Ferns are esculent. The 

 stems and leaf-stalks of Ferns are often covered with scales and Avith woody 

 matter. One {Davalia canarieiisis) is called Hare's-foot Fern' on this 

 account ; and another {Asj)iduun Baroniez) receives the name of Scythian, 

 or Tartarian-lamb, because, when prepared in a particular Avay, it resembles 

 that animal. 



Siih-ordcr 1. DaucBecc. Thecre united in masses, exannulate, opening 

 irregularly by a central cleft. Ex. Dangea. 



Sub-order 2. Ophioglossece. Thecse collected into a spike, formed at the 

 edges of an altered frond, distinct, exannulate, two-valved. Examples, 

 Ophioglossum, Botrychium. Ophioglossum vulgatum [pi. 54, ßg. 57), very 

 rare in the United States, Botrychium lunaria {ßg- 56). 



Stih-order 3. Osmundece. Thecae dorsal, or forming a separate stalked 

 mass (an altered frond), distinct, with a terminal or dorsal ring, more or less 

 incomplete, bursting lengthAvise by a regular slit. Examples : Osmunda, or 

 flowering fern, 0. regalis {pi. 54i,ßg. 55). 



Suh-order 4. Hynienophyllea'. Thecae marginal or dorsal, nearly sessile, 

 distinct, annulate, ring horizontal, complete, sometimes oblique, bursting 

 lengthwise. Examples : Hymenophyllum, Trichomanes, Lygodium. 



Sub-order 5. Polypod'mecB, or true Ferns. Thecae on the back of the 

 frond, pedicellate, or sessile, distinct, annulate, ring vertical, usually 

 incomplete, bursting irregularly and transversely. Aspidium filix mas 

 {pi. 54, ßg. 50) : a, a frond ; 6, rhizoma ; c, part of a frond, with sori ; 

 d, the indusium ; e and /, closed and open thecre. Adiantum capillus 

 veneris {fig. 54 a) ; 6, portion of the frond with sori ; c, opened theca. 

 Lomaria spicans (pZ. 54, ßg. 53) ; a, a fertile, and 6, a sterile frond ; c, a 

 portion of a frond, with sori ; d and e thee«. Asplenium trichomanes 

 {ßg. 51 a) ; b an opened theca. Scolopendrium officinarum {ßg. 52) ; 

 a, a frond ; b, a section magnified, showing two longitudinal sori ; c, an 

 opened theca. This species is found in the western part of New York. 

 Polypodium vulgare {ßg. 49^) ; a, frond ; b, rhizoma, with a frond stalk ; 

 c, portion of frond magnified ; c/, magnified sorus ; e, theca ; /, the same 



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