72 FORMS OF LEAVES. 



leaves much importance is attached in determining the species and other 

 botanical characteristics of plants. In some the species is decided 

 entirely by them. 



The periods of leaves are three. The seminal leaves come up from 

 the ground with the plant, and after nourishing it, they die. The 

 primordial leaves immediately follow the seminal and are like them in 

 form, position and size. The characteristic leaves are found in the 

 mature state of the plant. These changes do not however always 

 take place, the latter being in some plants the only ones which 

 appear. 



The forms of leaves are various and important in classification. A 

 leaf commonly consists of the leaf-stalk and disc. It is simple or com- 

 pound. The simple is when but one grows on a leaf-stalk and com- 

 pound when there are several, as in the rose. The obicular, or round 

 leaf, has its petiole, or base inserted into the centre and is peltate, as 

 the nasturtion. Reniform, or kidney-form, as the ground-ivy : it is 

 crenate, with margin scolloped and ciliate, fringed with hairs. Cor- 

 date, or heart-shaped, with accuminated or acute point, serated, or 

 with notched margin, like saw-teeth, as in the aster. Ovate, or egg 

 shaped : this is also abovate, oval, or eliptical. Lanceolate, as in the 

 peach. Linear, as in Indian corn and the grasses, and sheathing, or 

 enclosing the stem. Deltoid, or triangular, as in the lombardy poplar. 

 Sagittate or arrow-head shaped, as sagitaria. Jlcerose, or needle 

 shaped and clustered as in the pine ; it is subulate, like an awl, rigid 

 and evergreen, as with trees common to the mountains. Pinnatiftcd 

 and pectinate, like comb teeth and lyrate, with a broader segment. 

 Palmate, or hand-shaped, as passion flower, segments oblong like 

 fingers. Digitate, finger-shaped, distinct leafets, without palm, as 

 the horse chestnut. Cannate the bases of two united, appearing as 

 one leaf. Lobed, deeply indented at their margins and three or four 

 lobed, according to number. Sinuate, margins with deep round divisions. 

 Emarginate with slight indentation. Flabelliform, or fanshape, as in 

 some palms : such leaves are sold in China for fans. Ste.llated, or 

 whorled, as in a ring around the stem. Tubular, of which there are 

 numerous varieties, as the onion, etc. Some are hollowed out at the 

 base and contain fluid, deposited during rain. The pitcher plant of 

 Ceylon is a remarkable example of the tubular shape, being a cylin- 

 drical cup six inches long filled with pure water, with a lid opening 

 and shutting according to the weather. Primate, wing shaped, leaf 

 stalks opposite each other. Sinate, two leaves springing from the 

 petiole. Ternate, three leaves arising from the petiole and biternate, 

 triternate, decompound and tricompound. There are also other forms, 

 even to the burden of the science, which are not at first important to the 

 general reader. To those minute in their enquiries and making large 

 collections of leaves and flowers a more extended work will be neces- 

 sary. 



