48 



ANALYTICAL CLASS-BOOK OF BOTANY. 



(4) Oblong, the breadth greatly exceeding the 

 length, and nearly of the same breadth throughout, as in 

 figs. 7 and 12; 



(5) Oval, when both ends are somewhat sharply 

 rounded, as in figs. 5 and 6 ; 



(6) Diamond-form (rhomhoidal), as in the White 

 Birch, fig. 10; 



(7) Cordate (heart-shaped), the base forming two 

 rounded lobes, as in the Lilac and fig. 4 ; 



(8) E.ENIF0RM, a broader and shorter heart-form, as 

 in the Asarum, fig. 9 ; 



(9) Lanceolate, shaped like an ancient lance, with 

 a long and curved point, as in the Peach, fig. 8 ; 



(10) Spatulate, in the form of an ancient weapon, 

 called a spatula, fig. 11 ; 



(11) Saggitatb (arroiv-form), the base prolonged 

 backward, in two diverging lobes, as in the Calla and the 

 Arrowhead, fig. 13 ; 



(12) Hastate, the terminal lobes smaller, but still 

 more diverging, as in the Sorrel, fig. 14 ; 



(13) AuRicLED, the base winged with ear-like pro- 

 cesses, as in a species of Sage, fig. 18; 



(14) Clasping, the base of the leaf embracing the 

 stem, fig. 15; 



(15) AcEROSE (needle-shaped), leaves clustered in 

 long, slender and acute processes, as in the Pines, fig. 16 ; 



(16) Perfoliate, when the edges of a simple leaf 

 cohere, so that the stem appears to grow through it, as 

 in the Honeysuckle, fig. 17 ; 



(17) Connate, when the bases of two opposite leaves 

 cohere, so as to form a double perfoliate leaf, as in the 

 Boneset, and some species of Honeysuckle, fig. 19; 



(18) Sinuate, when a winding or sinuous line de- 

 scribes the margin, as in the Oak, fig. 1, Plate XIII. ; 



(19) Ltkate, with the notches more sharply defined, 

 and the terminal lobe larger and more rounded, as in 

 Shepherd's-purse, and the Turnip, fig. 2 ; 



(20) Pinnatifid, with the lobes reaching to the mid- 

 vein, and again divided, as in fig. 3 ; 



(21) EuNciNATE, cut into large diverging teeth, 

 which point backward, as in the Dandelion, fig. 4 ; 



(22) Linear, long and narrow, as in the Grasses, 

 fig. 5; 



(23) Pedate, with several deep lobes, somewhat 

 resembling a bird's foot, as in the Violet, which bears 

 its name, and fig. 7 ; 



(24) Palmate (hand-form), with several lobes re- 



Instances. What are the divisions of a simple leaf called ? Water Chest- 

 nut, describe. Compound leaf, define its principal forms and divisions. What 



sembling a hand with the fingers spread open, as in the 

 Passion-flower, and the Castor-oil plant, figs. 8 and 1 0. 



(25) Peltate, having the stalk fixed near the centre, 

 so as to give the leaf a shield-like appearance, as in the 

 Nasturtion, fig. 9 ; and 



(26) Oblique, with the sides of the base developed 

 unequally, fig. 13. 



■ (27) Ensiform (sword shaped), long and narrow, with 

 both surfaces alike, as in the Iris, fig. 6. 



(28) Decurrent, with the margin running down the 

 stem, as in the Thistle, fig. 14. 



276. In this plate are various modes of being cut, 

 or different forms of the lobed Leaf The lower leaves 

 of the Water Chestnut ( Trapa natans) are minutely 

 divided, while those which grow out of water are entire. 



COMPOUND leaf-forms. 



277. When a leaf is composed of more than one 

 piece or part, it is Compound. A compound leaf may 

 be distinguished from a deeply divided simple leaf by 

 the articulation,. or jointing together, of its several parts, 

 which, when the leaf decays, fall asunder. Leaves have 

 two principal modes of composition — the Pinnate Form, 

 as in the Locust, Rose and Pea, and the Ternate Form, 

 as in Clover. Other compound forms are either vari- 

 ations or combinations of these. 



278. The divisions of a compound leaf are called 

 Leaflets, and they exhibit all the peculiarities that dis- 

 tinguish simple leaves. The stalk that bears them is 

 called the Common Petiole, and the foot-stalk of each 

 particular leaflet is called the Petioldla. 



279. A Compound leaf is Pinnate, when the leaflets 

 are af&sed to each side of a common petiole, as in the 

 Eose Acacia, fig. 1, Plate XIV. Pimiate leaves are 

 also called Winged, because the leaflets serve as plumage 

 to waft them up and down in the air. 



A Pinnate Leaf is 



(1) Terminally Winged, ending in a single leaflet, 

 as in figs. 1 and 6 ; 



(2) Abruptly Winged, ending in a pair of leaflets, 

 fig. 4; 



(3) Interruptedly Winged, when the ordinary 

 leaflets are interspersed with smaller ones, as in the 

 Potato and the Agrimony, fig. 7 ; 



(4) CiRHHOSE, ending with a tendril, as in the Lentil, 

 fig. 12; 



do they exhibit? The Stalk of a compound leaf, its divisions. Describe the 

 forms. Pinnate, its varieties. Define each. 



