ASCIDIA OE PITCHERS. 



When two lobes at the base of a leaf are prolonged beyond 

 the stem and unite (fig. 156), the leaf is pafoKate (per, through, and 

 fofatm, leaf), the stem appearing to pass through it, as in Bupleurum 

 perfoliatum, and Chlora perfohata: when two leaves unite by their 

 bases they became ammatt (eon, together, and notes, born), as in 

 Lonioera OmETrC^f"'"; an ^ '*hen leaves adhere to the stem, forming 

 a sort of winged or leafy appendage, they are decurrtnt (efecurrt), to 

 ran down or along), as in Thistles. 



164. The vascular bundles and cellular tissue are sometimes devel- 

 oped in such a way as to form a circle, with a hollow in the centre, and 

 thus give rise to what are called jittxlar (jiftula, a pipe) or hollow leaves, 

 and to asddia (n2m*, a small bag) or pitchers. Hollow leaves are 

 well seen in the Onion. Pitchers are formed either by petioles or by 

 lamina*) and they are composed of one or more leaves. In some Con- 

 vallarias, two leaves unite to form a cavity. In Sarracenia (fig. 187) 

 and Heliamphora, the pitcher is composed apparently of the petiole of 

 the leaf. In Xephentes (fig. 181), and perhaps in Cephalotus. while 

 the folding of a winged petiole,/), forms the pitcher, a, the lid, e, which 

 is united by an articulation, corresponds to the lamina. This kind of 

 asridiiim is called calyptrimorphovs (zjcArcrf*, a covering, and p**Zr., 

 form), and may be considered as formed by a leaf such as that of the 

 Orange (fig. 185); the lamina, , being articulated to the petiole, />, 

 which, when folded, forms the pitcher. In Dischidia Raffiesiana. a 

 daubing plant of India, the pitchers, according to Griffith, are formed 

 by the lamina of the leaf, and have an open orifice into which the 

 rootlets at the upper part of the plant enter. These pitchers would 

 seem therefore to contain a supply of fluid for the nourishment of the 

 upper branches of the plant. In Utricularia, the leaves form sacs 

 called ampullae. 



Structure and Farm cf Leaves in the Great Dirwiwu cf the Vegetable 



Kingdom. 



165. KxgaMM r iiMjit. " !>**. In Ifra^gw, the vena- 

 tion is reticulated, the veins coming off at acute angles and forming 

 an angular network of vessels (fig. 136), and the trachea? communi- 

 cating with the medullary sheath. They are frequently articulated, ex- 

 hibit divisions at their margin, and become truly compound. There 

 are no doubt instances in which the veins proceed in a parallel man- 

 ner, but this win be found to occur chiefly in cases where the petiole 

 may be considered as occupying the place of the leaf. Examples of 

 this kind are seen in Acacias (fig. 188), as weQ as in Ranunculus 

 gramineus, and I-inon* 



' Edge r Tona-f otrledonou. t.-eaTe- Ir. E:_ :; : _-.:_>, '..- 



leaves do not present an angular network of vessels, nor do they er- 



