i 9 i S ] AASE—MEGASPOROPBYLLS OF CONIFERS 297 



The strobilus of Taxodium distichum possesses the same general 

 characters as described for Cr.yptomeria japonic a. 



The strobilus of Cunninghamia Davidiana (figs. 1 29-141) is 

 composed of a relatively large number of sporophylls. The scale 

 is united to the bract, with the exception of a small edge distal 

 to the insertion of the three inverted and slightly winged ovules. 

 The vascular supply to the sporophyll departs from the cylinder 

 gap as one large bundle; this bundle soon divides more or less 

 definitely into three; a further division takes place until a row of 

 fifteen or more normally oriented bundles results in the expanded 

 part of the sporophyll. In the earlier course of the branching of 

 the bundles weak strands separate from the lateral bundles and 

 swing around 180 so as to lie on the dorsal side of sporophyll; 

 some of these strands fork, so that an upper row of five or six 

 inverted bundles results; some of these bundles may begin blindly; 

 near the insertion of the ovules one or two strands bend toward 

 the chalaza and end there or a short distance behind the chalaza. 

 Owing to the fact that the bundles in the lower row adhere more or 

 less in the earlier course of division, it is difficult to determine 

 whether the median of the three first bundles passes undivided 

 into the narrow portion of the bract. It is accompanied, however, 

 by branches from the lateral bundles for some distance into the free 

 portion of the bract. At the tip and base of the strobilus are 

 sterile sporophylls. These have a vascular anatomy similar to 

 that of the fertile sporophylls, with the exception of the absence 

 of the upper inverted bundles in the former. Neither scale nor 

 ovules are present, but in place of these appear slight excrescences 

 with different staining reactions. 



Araucarineae 



The ovulate strobilus in the Araucarineae is composed of 

 numerous spirally arranged and closely compacted sporophylls. 

 Each sporophyll bears one inverted ovule, which is imbedded in 

 the sporophyll tissues in Araucaria, and naked and winged on one 

 side in Agatliis. Another feature of the Araucarineae of significance 

 in this connection is the branching of the sporophyll bundle in the 



