329 



ON THE STKUCTURE OF THE RESIN-SECRETING GLANDS IN SOME 



AUSTRALIAN PLANTS. 



By Marjorie I. Collins, B.Sc, Linnean Macleay Fellow or the Society in 



BOTAXY.* 



(With Test-figures 1-12.) 

 Introductiox. 



While engaged upon an investigation of the resinous secretion of the bud 

 in certain Australian genera of the Natural Orders Sapiiidaceae, Leijiiininoseae 

 (Sub-Order Mimo^eae) , Compositae, Goudeniaceae and Myoporineae, the writer's 

 attention was drawn to certain types of glandular hair, some of which have not 

 been recorded previously for these Orders. 



Since in all cases the developmental stages tlmiAv an interesting light upon 

 the structure of the mature gland, and since the results obtained might prove to 

 he of systematic value, it is thought desirabJij to place these observations on 

 record. 



Glandular hairs are described for the following species : — Dodonaea viscosa 

 Linn. [Sapindaceae). Acacia rupieola F. v. M., A. armata R Br., A. pi/criantha 

 Benth.. ,1. rerniciflua Cunn., (Leguminoseae, Sub-Order Mimosieae), Ixodea achill- 

 eoides R.Br., Heliclirysum semipapposum DeCand., and Hiimea cassiniacea F. v. M. 

 {Compositae). Mi/oporum serratuni var. ivfiilare R.Br., Mi/oporum serratum v^ar, 

 viscosum R.Br., and Eremophila latifolia F. v. M. (Myoporineae) . 



^ly thanks are due to Professor Osborne, University of Adelaide, for the 

 ■nterest he has slio'mi during the progress of the work. 



Description of Glandli.ar Hairs. 



N. 0. SAPINDACEAE. 



In his account of the Sapindaceae, based iipon Radlkofer's monograph {'2), 

 Solereder states that glandular hairs are widely distributed, and are present on 

 young leaves throughout the order (3, p. 230). The glands are described as being 

 multicellular peltate .scales, in which the cells of the shield either show a radial 

 arrangement (Arytera). or are polygonal and irregularly placed (Filicium, etc.). 

 It is recorded that in some genera, e.g., Melai/odifcus. the external glands are 

 analogous to glandular shaggj' hairs, since they possess a palisade-like secretory 

 region at the perijihery. 



In Dodonaea viscosa, which was examined by the present writer, the glandular 

 hairs resemble the Melanodiscus type. They are large in propoi-tion to the thick- 

 ness of the young leaf, and show a tendency towards radial arrangement of the 



•Tlie observations recorded in this paper were made while the writer held the posi- 

 tion of Demonstrator in Botany, The University of .\delaide. 



