158 CRYPTOGAMOUS OR FLOWERLE3S PLANTS. [SECTION 17. 



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

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

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

 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 leave" The early botanists thought this such a peculiarity that they 



606 507 602 



always called a Fern-leaf a FROND, and its petiole a STIPE. Usage con- 

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

 consists of SPORE-CASKS, technically SPORANGIA, which grow out of the 

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



FIG. 501. The Walking-Fern, Camptosorus, reduced in size, showing its frtiit- 

 on the veins approximated in pairs. 502. A small piece (pinnule) of a 

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

 kidney-shaped indusinm. 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 niagnilied. 5uf>. Sehi/;ra pusilla, a very small ami simple- 

 leaved Fern, drawn nearly of natural si/e. 506. One of the lobes of its fruit- 

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

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

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

 si/e; showing two rows of the linn spore-cases, which open transversely into two 

 valves. 



