FERNS. 



stalk ; the stalk being what has just been described as the 

 stipes, and the blade, the remaining part of the frond. That 

 portion of the stem or rachia that runs through the frond and 

 into its minute subdivisions is called the mAArih when it has 

 the leaf or leaflet attached to either side of it. The veins 

 branch from the midrib in straight lines ; they are often forked 

 in two branches. The organs of reproduction or spores are 

 attached to the veias which run along the underpart of tho 

 leaf. 



Different terms are applied to the frond according to its 

 shape. When it is uudivided and without indentation, as in 

 the Hart's Tongue fern {Scoloipendffvwm Vulga/re), it is termed 

 entire. When the frond is indented, as in the common Poly- 

 pody {Polypodium VvZgare), but the indentations do not reach 

 the main stem, or midrib, it is termed pinnatifid, which means 

 that it has incomplete branches or leaves, the divisions of 

 which do not reach as far as the stem. When the blade is 

 divided into lateral branches, or leaflets, as far as the stem, the 

 frond is termed pimmate, and the lateral offshoots from the 

 main stem are called pirmoB. The pinnae in their turn may be 

 either pinnatifid, or lobed, or pinnate ; and if the last-named, 

 then the entire frond is styled hi-pirmate, or twice-pinnate, and 

 the separate leaves of the pinnae are called pm/nules. When 

 the fronds on the pinnae are said to be Idbed, which in some 

 cases seems almost synonymous with the term pinnatifid, it is 

 meant that the divisions of the leaf which do not reach as far 

 as the midrib on the one hand, or the leaflets which spring 

 from the midrib on the other, are scalloped, or indented round 

 the edge. When the pinnae or secondary branches of a frond 

 are themselves also pinnate, or have lateral offshoots springing 

 from them as far as the stem, the whole frond is called trU 

 pirmate, or thrice-pinnate. But when it is stiU further divided, 

 or the tertiary branches are also pinnate, it is then termed de- 

 compow/nd. When the term circmnate is used, it is applied to 

 the manner in which the fronds and pinnae are coiled or rolled 

 up in the bud. The receptacle is that portion of any vein to 

 which the spore- cases or thecoe are attached. These are small 

 vessels which contain the seed ; the form of these often affords 

 the means of determining the classification of the plant. They 

 are collected together in little masses called sori, and these are 

 sometimes covered by a membrane termed an mdMsiMm or 

 meohicre. They are always found on the under surface or th» 

 edse of the leaf; when they are in the former position they aro 



* 80S 



