RANALES 393 



ruminate endosperm suggests relationship to Euponmtia and the 

 Myristicaceae, rather than to the MagnoUaceae, but is, perhaps, an 

 ancient character retained in several lines. The receptacle ranges from 

 convex to somewhat concave; in Calijcanthus and Rosa, it is deeply 

 concave. 



The wood is remarkably uniform for so large a family; generic differ^ 

 ences in the wood are difficult to determine. (Asimina stands apart from 

 other genera in its ring-porous wood. ) The vessels are simply perforate; 

 the wood parenchyma is apotracheal, in fine, regularly spaced, con- 

 centric lines (a character that differentiates the wood of this family 

 from that of all other families); the rays are chiefly uniseriate, a few, 

 multiseriate. This wood is more specialized than that of the MagnoUa- 

 ceae in vessel type and differs greatly in its parenchyma distribution. 

 The phloem is stratified in some genera, an advanced character for a 

 primitive family. 



Anatomically, the flower resembles that of the MagnoUaceae in the 

 presence of a cortical vascular system, but this system is less strongly 

 developed than that of the magnolias. (The vascular system is less well 

 known in detail than that of the magnolias; apparently, it has been 

 described only in Asimina and Annona.) In Asimina, the cortical 

 bundles are derived from the stele of the peduncle below the calyx and 

 become inversely oriented or concentiic. No uniform plan of arrange- 

 ment is followed. Tlie sepals receive all their several traces from the 

 cortical system; the petals receive the median trace from the stele of 

 the axis, their several lateral traces from the ascending cortical bundles. 

 The stamens each receive a single trace. (This single-trace supply, the 

 most advanced condition in the MagnoUaceae, is found only in a few 

 species of Michelia.) The lower stamens are supplied from the cortical, 

 the upper from the axial bundles. Some of the "stamen traces" branch 

 and supply more than one stamen. At this stamen-trace level, other 

 branches tie together tlie cortical and axial systems. The distal parts of 

 the cortical system are used up in the formation of carpel traces, three 

 to each carpel. (The vascular system of two species of Aimona differs 

 from that of Asimina in no essential way.) The floral cortical system of 

 the Annonaceae, as compared with that of the MagnoUaceae, has been 

 called both "only partially developed" and "reduced." 



Only four examples of a cortical vascular system in the floral axis o£ 

 angiosperms appear to have been described — those of the MagnoUaceae, 

 Annonaceae, Calycanthaceae, and Himantandraceae; others may exist 

 where cortical bundles are present in the stem, as in Justicia (Dian- 

 thera ) . 



The patterns of the cortical systems of the MagnoUaceae and the An- 

 nonaceae are similar and differ from that of Cahjcanthus. The two types 



