296 



CYATHEACEAE 



[CH. 



as "not scaly," and it is possible that some others may, like Lophosoria and 

 Metaxya, bear only hairs. This feature contrasts strongly with the hairs of 

 the Dicksonieae, in which Family scales are absent. In many of the 

 Cyatheaceae the scales are borne upon peg-like outgrowths, comparable to 

 those bearing the stiff branched hairs of Gleichenia pectinata (compare Vol. l, 

 Figs. 191, 192). It is probable that the scales are the result of a webbed and 

 flattened development of such hairs. The pegs persist after the scales fall 

 away, and constitute the "armature" of hard woody spines present in certain 

 species belonging to all three genera, but most frequently in Heviitdia and 

 Alsophila (see Fig. 567, also Vol. I, Fig. 191). 



Fig- 558- Part of a pinna of Hemitelia Karsteniana Kl. 

 showing many vein-fusions. (After Mettenius.) 



Anatomy 

 The stems of the Cyatheaceae have a highly complex structure. But it 

 is readily intelligible in terms of the simpler states seen in GleicJiciiia and 

 LopJiosoria: for the former genus gives the steps from protostely to a fully 

 developed solenostele, while the latter leads on to the dictyostelic state. 

 A well-developed dictyostele is present in the adult stem of all the three 

 genera, giving off highly disintegrated leaf-traces and numerous root-traces. 

 But there is in addition a medullary, and sometimes also a cortical accessory 

 system. Thus a high complexity is attained. It will be unnecessary to 

 repeat here the detailed descriptions already given elsewhere (compare 

 De Bary, Coinp. Anat., Engl. Edn. pp. 291-294. Origin of a Land Flora, 

 p. 604. Also /^tr/w, Vol. I, p. 156, Figs. 150, 151). But the inconstancy of the 

 accessory strands ma}' be noted. A medullary system is present in the adult 

 stem in all three genera. But while a cortical system also is present in 

 Cyathea Imrayana (Vol. I, Fig. 1 50), it is absent from Hemitelia setosa (Vol. I, 



