14 VV'iass, A TyloJcHdron-like hossil. 



KXI'LANA'IION OK I'LATJC II. 



/'/]C- I- — Secretory passage (mucilage? canal) from pilli of 'lylo- 

 (IcndroH Coivardii \n transverse section. Several of the 

 surrounding cells have undergone division. x 65. 



y'/i,'. 2. — 'I'wo adjacent secretory canals of the pith. x 65. 



^''K- 3- — Apparent fusi(;n (jf two adjacent canals. x 65. 



/'/.V- 4- — Secretory canal showing repeated division of the sur- 

 rounding cells of pith. 'I'he dolled lines indicate the 

 walls which could not be clearly distinguished in the 

 section. x 65. 



/'/i,'. 5. — J^ongitudinal view of secretory canal. 'I'hc horizontal 

 elongation of the [)arei;chyma cells of the i)ilh can be 

 clearly seen. x 65. 



J'ig. 6. — Portion of transverse section across tlx- imier margin of 

 the vascular tissues showing a grouj) of tracheids 

 isolated in the [)arenchyma of the pilh. x 150. 



J'^S- 1- — J'^iifi'iil longitudinal section through [)ortion of vascular 

 tissue showing two isolated scalariform tracheids to the 

 inside (left) of the main mass of tracheids. x 150. 



I'ig. 8. — Portions of tracheids from radial longitudinal section 

 showing various forms of pitting. 

 a. Horizontal pits, 



Ik Two rows of bordcri'd i)its and one " fused " pit 

 at base. The latter closely resembles the pits 

 seen in a. 



c. Two alternate rt)ws of i)its. 



d. Single row of pits. All x 230. 



