INDEX 



149 



Ontogeny, of sieve-tube elements, 

 !)4-i)7 

 of stele, 104-l(»(i, 131-132 

 of stoma, 48 



of trac'hearv elements, 83-80 

 of vessel elements, 83-84 

 Organismal theorj', 1 

 Osteosclereides, structure and oc- 

 currence of, 68 



PALISADE parenchyma, in leaf 



of Syringu, 125 

 Pajier, cellular composition of, 90 

 Parenchyma, critique of concept 

 of, 57 

 form of cells of, 57-58 

 functions of, 58 

 material for study of, 59-60 

 photosynthetic, 59-60 

 j>r(jtoiilasts of, 58-59 

 regressive differentiation of, 58- 



59 

 storage, 59 



structure and chemistry of Avails 

 of, 58 

 Pear, stone-cells of, 70 

 Pelargonium,, cell walls in pith 

 and cortex, 11 

 druses in, 5 

 multicellular unbranched hairs 



of, 53 

 study of epidermis of, 49 

 study of stem of, 108-111 

 J^eJIioiiia, starch-containing- cldor- 



oplasts of, 4 

 Tepcromia, nmltiple epidermis of, 



50 

 l-'erforation-plate, in vessel ele- 

 ments of Pferidiuni, 88 

 types and evolution of, 83 

 Perforations, distinctive of vessel 

 elements, 81 

 evolution of, 82-83 

 ontogeny of, 83-84 

 types of, 83 



Pericycle, critique of, 74 



functions of in root, 132-134 

 Pericyclic fibers, in stem of Ciicur- 

 ^ bit a, 98 

 in stem of Pelargonium, 109 

 Periderm, function of, 107 

 origin of in roots, 134 

 structure and development of, 

 107-108 

 Persimmon, endosperm of, 8 

 Petunia, study of stem hairs of, 



2-3 

 Phellem (see also Cork), origin 



and structure of, 107 

 Phelloderm, origin and structure 



of, 107 

 Phellogen (see also Cork cam- 

 bium), origin and func- 

 tions of, 107-108 

 origin of in roots, 134 

 Phloem, complex structure of, 93 

 fibers in, 74, 76, 94, 113 

 functions of, 94 

 of Cucurbita, 98-99 

 jiarenchyma, of Cucurbita, 99 

 rays, in stem of Tilia, 114 



origin of, 27 

 structure of, 94 

 Phloroglucin and hydrochloric 



acid, use as stain, 141 

 Phloroglucinol, use for bast fibers, 

 77 

 use for sclereides, 70-71 

 use for tracheary elements, 87 

 Picea, structure of shoot apex, 25 

 Pine, resin canals of, 117 

 secondary xylem of, 117 

 Piniis, bordered pit-pairs in, 13, 

 88-89 

 resin canals of, 117 

 study of cambium of, 28 

 study of leaf of, 128 

 study of phloem of, 99 

 study of tracheids of, 88-89 

 Pit aperture, use of term, 11 



