Xii 1NTI{«)1>ICTI<)N'. 



.15. A ('(iniple'ti' K-:if (•()in[)risi's tlic Bhxih , tlio Slnlk, ami a pair of Stipules; 

 liiit those tlirec parts are not always present in one leaf. 



3G. Tlio Blade, Linih, or Lamina, is the expanded part, and presents a great 

 variety of forms. It is simple, when it consists of a single ])ieee, liowever cut or 

 divided ; and cumimunil, when of two or more distiiut pieces (Itajiits), which 

 .separate hy a joint. 



.'?7. Tiic Stalk, or Petiole, connects the blade with the stem. When it is 

 wanting, the leaf is said to be sessile. Tiie stalk of a leallet is called a Piliolule. 



38. Tiie Stijiiiles arc ajjpendages of various forms, placed one on each side at 

 tiie base of the petiole. They are separate, or else united with the petiole, or 

 with each other, wlien they occasionally ft)rtn a slieath (Ocltrea) artiund the 

 stem above. The stipules of a leaflet are called Stiptls. 



39. The manner in which the veins are distributed through the leaf is called 

 Venation. 



40. There are two modes of venation ; viz. paralkl-veined, or nerved, when 

 several simple veins, or ribs, run parallel from the base of the blade to its apex ; 

 and reticulated, or netied-veinid, when the veins divide into numerous primar\' and 

 secondary branches (veinhts), which again unite to form a kind of network. 



41. The latter mode embraces both the pinmitdy reined, or feather-veined leaf, 

 where the petiole is continued through the middle of the blade, giving off at in- 

 tervals lateral veins; and the palmately veined or ribbed leaf, when it divides at 

 the apex into three or more strong branches. 



42. The manner in which leaves arc divided corresponds with that of their 

 venation. 



43. A simple pinnately veined leaf becomes pinnatijid, when the incisions 

 (sinuses) extend about half-way to the midrib, or continuation of the petiole ; 

 and pinnatelji divided, when they extend down to the midrib. A compound pin- 

 natel}'' veined leaf is, of course, pinnate, with the separate leaflets arranged on 

 each side of the common petiole. When this is terminated by a leaflet, the leaf 

 is said to be odd-pinnate, or unequally pinnate, and when it is wanting, abruptly 

 pinnate. 



44. So, also, the palmately A'cined leaf becomes palmately cleft or divided, 

 when the incisions are directed toward the base of the blade. When the divis- 

 ions consist of separate leaflets, it becomes palmately compound. 



4.5. Floral leaves, or those from the axils of which the flowers arc developed, 

 arc called Bracts; and those which arc borne on the flower-stalk, Bractlets. 



6. The Flower. 



46. A Flower consists of those parts, or organs, which arc concerned in the 

 production of seed. Like the leaf, of which its jjarts are a niodirtcation, it is 

 developed from an axillary or terminal bud. 



47. The manner in which the flowers are an-angcd on the stem or branches is 

 termed the Inflorescence. 



48. There are two modes of inflorescence ; viz. the indefinite, or centripetal, 

 where the flowers all arise from axillary buds, the lowest or outermost expand- 

 ing first, while the axis elongates indefinitely from the terminal bud ; and the 

 definite, or centrifugal, where the flowers arise from the terminal bud, first, of the 

 main axis, and successively from that of the branches. 



