97 



Euphorbia 



Fagus 



Picus 



Praxinus 



Gleditscliia (Tison) 



Hamamelis ( Tison) 



Hedera- 



Hedychium 



Hellconia 



HiJinulus (OJuTjeuf) 



Inula 



Jatropha 



Jugland 



Koelreuteria 



Latania 



Laurus 



l^igustrura 



IiOranthus 



Losropterygium 



Madura 



Mansoa 



Blaranta 



Hicania 



Mo rue 



Musa 



Ochtoma 



plea 



Ostrya 



Passiflora 



Paulrmmia 



Perilla 



Hiarbitis 



Philodendron 



Phyllanthsu 



Picea (Raatz) 



Pinus (Raatg) 



Piratinera 



Pistacia 



Plantageo 



Plat anus 



Populus 



Portulaca 



Prunus (y/ieler) 



Pterocarya 



Quercus 



Bhus 



Kicinus 



Robina 



Rosa (Matae) 



Rubia 



Rtuilex (Dutailly) 



Salix 



Sambucus 



Santalxim 



Schinus 



Sideroxyltun 



Solanum 



Sparmannia 



Stigmatophyllum 



Strelitzia 



Taraxa crura 



Tbunbergia 



Ulnus 



Urtica 



Xanthoxylon (Tison) 



Vitis . 



(104) Bo far as I kiioTCst only Cyathea ins ignis may be consid- 

 ered as a representative of vascular cryptogams , in whicli 

 according to Conwentz (loc. cit. p. 35) , tyloses appear 

 in the old petioles. 



Two more important points are to be settled - the giies 

 tion as to the dtiology of ty^joses in the ducts and the 



question as to their physio log-ical si^nifioance . 



It has not yet been made sufficiently clear, uiider 

 what conditions tyloses are produced. Beyond doubt, the 

 parenchyma cells are stimulated to tylose formation throng 

 injury to the branches, roots, etc. Tylose formatio^a ap- 

 pears as well in'artifical pruning etq^, , as in ^e "physio- 

 logical " injury, which defoliation brings v^th it; in Ro- 

 binia only a few hours suffice to bri^ about the formation 



