158 CRYPTOGAMOUS OK FLOWERLESS PLANTS. [SECTION 17. 



minate upward in a leaf-stalk. The subterranean trunk or stem of any 

 strong-growing herbaceous Tern shows a similar structure. Most Ferns 

 are circinate in the bud; that is, are rolled up in the manner shown in Kg. 

 197- Uncoiling as they grow, they have some likeness to a crosier. 



487. The fructification of Ferns is borne on the back or under side of 

 the leaver The early botanists thought this such a peculiarity that they 



603 807 MS 



always called a Fern-leaf a Frond, and its petiole a Stipe. Usage con- 

 tinues these terms, although they are superfluous. The fruit of Ferns 

 consists of Spoke-cases, technically Sporangia, which grow out of the 

 veins of the leaf. Sometimes these are distributed over the whole lower 



Fio. 501. The Walking-Fern, Camptosorus, reduced in size, showing its fruit- 

 dots on the veins approximated in pairs. £02. A small piece (pinnule) of » 

 Shield-Fern : a row of fruit-dots on each side of the midrib, each covered by its 

 kidney-shaped indnsium. 503. A spore-case from the latter, just bursting by the 

 partial straightening of the incomplete ring; well magnified. 504. Three of the 

 spores of 509, more magnified. 505. Schizsea pusilla, a very small and simple- 

 leaved Fern, drawn nearly of natural size. 606. One of the lobes of its fruit- 

 bearing portion, magnified, bearing two rows of spore-cases. 507. Spore-case of 

 the latter, detached, opening lengthwise. 508. Adder-tongue, Ophioglossum: 

 spore-cases in a kind of spike: a, a portion of the fruiting part, about natural 

 •izej Bhowing two rows of the firm spore-cases, which open transversely into two 

 wives- 



