196 



THE MARATTIALES 



Forms of Angiopteris occur from Polynesia to Madagascar and northward as 

 far as the Himalayas. The genus also occurs in northern Australia. 



The anatomy of the adult plant has been investigated more thoroughly than 

 that of any other member of the Marattiaceae. The most recent account of the 

 anatomy is that given by Miss Shove (Shove 1), while Farmer and Hill have care- 

 fully investigated the vascular system of the young sporophyte. A number of prep- 

 arations were made by the writer for the purposes of comparison with the other 

 genera, but no attempt was made to follow out in detail the extremely complicated 

 vascular skeleton of the adult sporophyte. Farmer and Hill (Farmer 3) have given 

 a detailed account of the development of the vascular system in the young sporo- 

 phyte oi Angiopteris, so that it was not thought necessary to make a large number 

 of preparations of this species, the material of which was collected at the same place 

 where Farmer obtained his plants. However, as these authors did not trace the 

 development of the young bundles from the apical meristem, it seemed worth while 

 to examine this point for the purpose of supplementing their account based upon 

 the study of the fully developed vascular skeleton. 



Fig. 178. — Four longitudinal sections of a young sporophyte of Angiopteris. 



The vascular system begins, as was recognized by Farmer in an earlier paper 

 (Farmer 1), as a single strand connecting the root and cotyledon, exactly as is the case 

 in the other Marattiaceae. In the further study of the development of the vascular skel- 

 eton Farmer and Hill employed the method of constructing a model of the vascular 

 system, built up of superimposed sheets of wax, corresponding with the outline of 

 the vascular bundles seen in the serial sections. The figures which they give, 

 drawn from such models, show very clearly the relation of the vascular strands 

 which make up the complicated skeleton in Angiopteris. The assumption is made 

 that the single stele found in the young plant is really a cauline structure, the leaf 

 traces being subsidiary. The early history of the vascular system of the young 

 sporophyte is given by them as follows : 



"The vascular skeleton in the young plant oi Angiopteris consists of an axile 

 rod of tissue, from which strands are given off to the roots and leaves respectively. 

 The first lateral root is given off at a point not quite opposite the formation of the 

 first leaf trace. It is separated from it by about 130°. The regular relation be- 

 tween the leaf and the corresponding root is, however, soon lost. The gaps produced 

 by the early leaf traces are very small and are immediately made good above. The 



