640 MAESILEACE^ OE EHIZOCAEPE^ — LYCOPODIACE^. 



pedatum (Canadian Maiden-hair), and A. Oapillus Veneris (true 

 Maiden-hair). 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 with wooUy matter ; DavalUa 

 caTiariensis is called Hare's-foot Fern on this account, and Oibotmm 

 Barometz receives the name of Scythian or Tartarian-lamb, because, 

 when prepared in a particular way, it resembles that animal. 



Order 217. — Maesileace^, or Ehizocarpe^, the Pepperwort 

 Family (p. 279). Stem wanting. Leaves often stalked, with the 

 lamina divided into three or more wedge-shaped pieces ; sometimes the 

 lamina is abortive ; vernation circinate. Eeproductive organs near 

 the root or along the petiole, enclosed in an involucre. At the base 

 of the leaves or petioles stalked sporocarps are formed, which are 2-4- 

 celled or 2-4-valved ; they contain antheridia (microspores) and spor- 

 angia iu separate cavities (fig. 504, p. 279), or there may be separate 

 sporocarps for antheridia and archegonia (fig. 505, p. 279). The 

 spore forms a prothallus bearing one or more archegonia. — Creeping 

 or floating plants, found in ditches and pools in various parts of the 

 world, more especially in temperate clirnates. They are not put to 

 any important use. Marsilea Macropus or Salvatrix is the Nardoo plant 

 of Australia, the sporocarps of which have been used as food by 

 travellers in that country. There are 4 genera and upwards of 40 

 species. Examples — Marsilea, Pilularia, Salvinia, AzoUa. 



Order 218. — LYOOPbMACEiB, the Club-moss Family (p. 278). 

 Stems creeping or corms ; annular vessels in the axis. Leaves imbri- 

 cated, more or less setaceous, sometimes subulate. Sporangia, axillary 

 and sessile, 1-3-celled, opening by valves or indehiscent ; often of two 

 kinds. One, round, reniform or crescentic, consisting of antheridian 

 cells, with spermatozoids ; the other, called oophoridium (iiov, an egg, 

 and pofs'iD, I bear), of a roundish or tetrahedral form, opening by two 

 valves, and enclosing four large spores capable of germinating ; these 

 spores contain an internal prothallus on which archegonia are formed. 

 In Lycopodium we. meet with one kind of theca containing numerous 

 small spores ; while in SelagineUa there are microspores or antheridia 

 (figs. 498, 499, p. 278) at the upper part of the cone-like fructifica- 

 tion (fig. 497, p. 277) ; while at the lower part there is a sporangium 

 containing macrospores (fig. 501, p. 278), producing a prothallus 

 bearing archegonia, which are fertilised by the spermatozoids of the 

 antheridia from the interior of the microspores. The fertilisation of 

 Lycopodium has not been fuUy ascertained. In Isoetes the two kinds 

 of reproductive bodies are embedded in the substance of the base of 

 the leaf. Isoetes is put by many in a distinct order, IsoETACE.ffi:, 

 QuiHwort Family. They difi'er from Lycopods in their habit, and in 

 their stem, which is a perennial, woody caudex increasing by annual 



