334 



RESIX-SECRETIXG GLANDS IX SOME AUSTRALIAN' PLANTS, 



vertical division in both gland rudiment and basal epidermal cell (Text-figs. 9a-c, 

 ]0«-b). This vertical division is fdllowed by a series of transverse divisions 

 parallel to the first transverse wall formed. In the case of Helichrnsum semi- 

 papposum the median vertical division is followed by one transverse division only. 

 The gland cells then increase in size, the upper pair being markedly inflated 

 (Text-fig. 10 c, d). In Ixodea and Humea there are three transverse divisions fol- 

 lowing the median vertical division, so that the mature gland possesses two vertical 

 rows, each of four cells surmountin.i;' a basal epidermal cell (Text-figs. 9e-f). In 

 the glands of a species of Chri/santliemtim figured by Solereder after Yogi (3, i., 

 p. 458, fig. 103/f.). only two transvei-se divisions iollow the vertical divisiim. 



N. (>. MYOPOBIXEAE. 



Glandular hairs are of common occurrence in the two genera of Mi/oporineae — 

 Myoporum and Eremophila. Solereder states tliat these glandular hairs possess 

 "varied structure within the individual species, but agree in the tact that the 



Jfef 



Text-fig. 9. — (a-/). Stages in the development of the glandular hairs of Ixodea achille- 

 oides ; g, h, surface and lateral views of glandular hairs, (x 280). 



Text-fig. 10. — (a-d). Stages in development of the glamlular hairs of Helic/nrsiuii seini- 

 papposuiii. (x280). 



ghuididar lu'a<l is, in ahimst all cases, divided by vertical walls only" (3, p. ()26). 

 (ihindular and clothing hairs are also known to occur in the same leaf-bud, and, 

 according to Solereder, transitional forms of a d\ial nature are often found (3, p. 

 (i271. These facts suggest that glandular hair formation in the Mf/oporineae is 

 in an unstable condition. Observations made by the writer upon gland develop- 



