602 R. J. HARVEY-GIBSON AND MINNIE BRADLEY ON 



independent course through the next internode, but more usually the median bundle 

 only runs distinct, while the lateral bundles fuse with adjacent bundles. This species 

 shows occasionally two axillary branches in the axil of each leaf. 



G 1 nudum corniculatum. — The leaf-trace consists of several strands which follow 

 fairly independent courses down the stem, the vascular tissue from the axillary 

 branch being intercalated between the leaf-trace strands. Fusion then takes place 

 between these bundles and the stem bundles, so that the number of cords in the stem 

 is not much increased over that present above the leaf entry. 



In Bocconia microcarpa the leaf-trace usually consists of seven strands which 

 (save the median one) split and again reunite in the basal region of the petiole before 

 entering the stem cylinder (fig. 37). The mode of entry is very gradual. First of 

 all the vascular system of the axillary branch separates and the median bundle from 

 the leaf enters ; then the lateral bundles of the axillary branch separate to permit 

 the lateral cords of the leaf-trace to enter between them, but there are no immediate 

 fusions. Further down the bundles of the branch fuse and taper off, becoming much 

 less prominent than the leaf-trace cords intercalated between them. The entry of 

 the basal leaf-traces is effected in a similar manner. 



In Eschscholzia californicn the leaf-trace is formed of one large median and four 

 to six smaller lateral bundles. These latter fuse among themselves, while the median 

 bundle remains distinct. As a rule the median and lateral cords do not enter by the 

 same gap, but the former is separated from the latter by certain stem bundles. The 

 median bundle retains its individuality for a considerable distance, while the lateral 

 strands merge into the stem cylinder. 



In Hypecoum grandijiorum the leaf-trace is uni- or tri-fascicular. The upper 

 leaf-trace, which is usually unifascicular, is inserted between two segments of a stem 

 bundle, and maintains its independence through an entire internode. Although the 

 phyllotaxis is a 2/5 spiral, the first two leaves arise so close together that the leaf- 

 traces are inserted practically simultaneously. When the leaf-trace is trifascicular 

 the method of entry is identical with that of Eschscholzia californica ; many varia- 

 tions, however, occur. 



In Dicentra formosa the traces are unifascicular and enter without forking, 

 while the vascular tissue of the axillary branch arranges itself half on either side of 

 the entering leaf-trace. The radical leaves have generally three main bundles and 

 several smaller ones, all of which enter by one gap ; and, although at first they 

 remain independent for some time, they gradually fuse in groups and ultimately lose 

 their identity in the stem cylinder. 



The leaf-trace in Adlumia cirrhosa consists of an arc of several independent 

 strands which enter the stem system by one gap. Their number is, however, reduced 

 to five by lateral fusion before actual entry (fig. 38). Two marginal strands, one on 

 either side, fuse with adjacent stem bundles — sometimes simultaneously, sometimes 

 in succession. Three bundles remain, of which the two lateral unite with these com- 



