INTRODUCTION TO BOTANY. y 



Leaves are, 



amplexicaia, OTstm-clasping, when the sessile base of the blade is not 



hori^ont^aT*' ^''™'' '^'''"^ '''" ^^'' "^^ ^ ^^' clasping the stem 

 perfoliate, when the base of the blade not only clasps the stem, but 



closes round it on the opposite side, so that the stem appears to 



pierce through the membrane of the leaf itself. 

 decurrent, when the edges of the leaf are continued do^^oi the stem 



so as to form raised lines, or narrow stem-borders called tvings. 

 shcathn.g, when the base of the blade, or of the expanded petiole 



fonns a vertical sheath round the stem for some distance above 



the node. 



ft'o^T^'.'^.v'^''" ^""""^ .^T^""'^ are called radical, when they spring directly 

 fiom a rhizome or stock, or are inserted so close to the base of a stem as to 



sE"frnST^^'-"'^^.-^°°' °/.^*^^^- L^^--« -^^ .«'?4 when the? 



spimg from the mam portions of the stem ; rameal, when from a branch^ 



37. Eadical leaves are rosidate, when they spread in a circle on the 



pound ; cauhne or ranieal leaves are>...r Jor tufted, when the leave of 



two or more nodes are brought close together in a pencil-like tuft by the 



38 Leave^re ^t^^^^des; as in Aspalathus, Asparagus, eil 



simple ^nd^ entire, when the blade consists of a single piece, and the 



margm is nowhere indented ; simple being used as the opposite to 



compound and entire as the opposite to dentate, hhed, or divided 



c./t«^., when bordered with straight hairs, or hair-like teeth ; cilia. 



late when the hairs are small. 

 ^e^/^^«/^, or toothed, when the margin is sHghtly notched at re-ular 

 distances into what have been compared to teeth. Such leaves 

 are serrate when the teeth are pointed like those of a saw • 



';:r /V"" ^^r* ^^^^ ^^^^^^^^- ^^^ diminutives serrulate, 

 <l^^'nlcite are usedtoexpress minutely serrate or minutely crenate 

 The hollows between the teeth are respectively called irra^e^m 



oj-LlCI C) OKltll) CS* 



sinuate v^lcen the margin is bluntly indented, ^dth broad, shaUow, 

 and irregailar hollows bejwecn the projections (Hke the bays 

 between the headlands of a coast) ; wavy, or undllate, when the' 

 edges of such a leaf are not flat, but bent up and down (like 

 calle7Z«l ' "'^^' ^""^ ^"^"^^ between the projectionLe 



lobed or cleft, v^hen more deeply indented or divided, but so that 

 the mcisions do not reach the midiib or petiole. The teeth or 

 sections of such leaves are called lobes 



"^'"'to'dMpH^^ff ^1f T "'^'^ ^" ^^'^^ ^^ P^^i^^^' b^t the parts 

 so duided off, called segments, do not separate fi-om the petiole 

 even when the leaf falls without tearin- ^ ' 



....,.W when divided to the midi-ib or petiole, and the parts so 

 di^aded off caUed leafets, separate, at least on the faU of the 

 leaf from the petiole, as the whole leaf does from the stem, 

 ithout tearing. The petiole of a compound leaf is sometimes 

 called the common petiole (because conuuon to all the leaflets 

 which often are united to it hy pet iolales or incHvidual petioles') ' 

 sometimes the rachis, a term also appHed to the inflorescence 



from' thoT.ll''''^ "''''''' °'' ^f ' distinctly marked by veins, which, starting 



hom the stalk diverge or branch as the blade widens, and spread over S 



yst:r(nO)^:'Se.f^^¥f veins, represent the woody a'nd v^s^Sar 



s^bttm (1/U) ol the leaf. The principal ones, when prominent, are often 



