CELL-CONTENTS AND FORMS OF CELLS. 283 



goniaceae, Berberidaceae, Bixaceae, Borraginace^, Burseraces. 

 Capparidacese, Capnfoliaceae, Caryopyhllaceae, Chenopodiaceae, 

 Combretaceae, Compositae, Convolvulaceae, Cornacese, Crassulaceae, 

 Cruciferae, Cucurbitaceae, Dipsaceae, Ericaceae, Euphorbiace^, 

 Fagaceas, Geraniaceae, Hippocastanaceae, Hydrophyllaceae, Labi- 

 atae, Leguminosae, Malvaceae, Melastomataceae, Meliaceae, Meni- 

 spermaceae, Moraceae, Myrsinaceae, Nolanaceae, Nyctaginaceae, 

 Nymphaeaceae, Piperaceas, Platanaceae, Plantaginaceae, Polemoni- 

 aceae, Polygonaceae, Portulacaceae, Primulaceae, Rosaceae, Ru- 

 taceae, Sapindaceae, Saxifragaceae, Scrophulariaceae, Simarubace^, 

 Solanaceae, Sterculiaceae, Theaceae, Tiliaceae, Umbelliferae, Ul- 

 maceae, and Valerianaceae. 



3. Glandular leaf-teeth, as the name would signify, include 

 the glandular hairs formed on the lobes of leaves. They vary 

 in structure and may secrete mucilage, as in the Violaceae (Fig. 

 120) and in some of the Compositae, or they may secrete, in addi- 

 tion, resin, as in the Rosaceae, or calcium oxalate, as in the 

 Saxifragaceae. 



4. Special forms of multicellular glands are found in the 

 Aceraceae, in which a pair of glands are fused together. In some 

 of the Compositae and Moraceae a group of glandular hairs are 

 united. Other special types also occur in the Droseraceae, Ana- 

 cardiaceae, Leguminosae, etc. 



5. Hair-like external glands having a complicated structure 

 have been observed in a number of families. They are limited 

 to certain portions of the plant, being found in the Apocynaceae 

 at the base of the leaves and in the Rubiaceae only on the stipules. 

 They are usually very large, secreting considerable mucilage and 

 resin. The glandular, shaggy hairs occurring on the stipules in 

 the Rubiaceae are of this type, the secretion being often so abundant 

 that the young leaves emerging from the stipular sheath are 

 coated with this resin, which is even retained by the mature 

 leaves. 



IL NoN-GLANDULAR Hairs are of three general types: i. 

 Simple hairs (Figs. 148, 151), which may be unicellular or uni- 

 seriate, — i.e., consisting of a series of superimposed cells. 2. 

 Peltate or stellate groups (Fig. 153, D, E, H, K), consisting of 

 two or more hairs united at the base and spreading like a star. 



