i66 BLECHNOID FERNS [CH. 



hypothetical starting-point for the Blechnoid series. It was necessary to 

 state these facts at the outset so as to fix the terminology, and to aid lucid 

 description. 



Here it may fitly be noted that in no natural group of Ferns do the 

 observations of Hannig on the occurrence of a perispore bring such in- 

 consistent results as in the Blechnoids and Onocleoids. He found {Flora, 

 Bd. 103, 191 1, p. 339) that a perispore is present in Sadleria, Doodia, and 

 Brainea, and also in Phyllitis {Scolopendritivi) : but it is absent in Blechnum 

 and Woodwardia, and also in Stenochlaena {Loinariopsis). Such results cut 

 across what is certainly a very natural family, as judged by many other 

 features. It is worthy of remark, however, that the Onocleeae are similarly 

 inconstant: for he states that a perispore is absent in Onoclea sensibilis, but 

 present in Matteiiccia {Stnithiopteris) orientalis and germanica. Such facts 

 need not destroy confidence in this valuable diagnostic character for general 

 use: the facts for the Ferns at large are too consistent for that. For 

 instance, it is very constantly present in the Aspidieae and Asplenieae, 

 and absent in the Pteroids. But the fact that inconstancy occurs both in 

 the Onocleoid and the Blechnoid Ferns appears to strengthen the relation 

 between these families, a relation which underlies the whole phyletic 

 argument of this Chapter. 



Blechnum (§ Lomaria) tabulare (Thunbg.) Kuhn 

 In habit this is a dwarf Tree-Fern (Fig. 686). It is synonymous with 

 Lomaria Boryana (Swartz) Willd., and it resembles in general characters the 

 more familiar B. capense (L.) ^j-^^^^^aaz^^ 



Schlecht {= Lomaria procera m^® % )•) 



Spr.). Its stem may be 4 feet \\% (§) / ^"^""^^^^^^^iv, 



high, and the leaves are very l\ % 7 /l^--^ ^^ ^^^ 



firm and coriaceous, and simply i/^ "^^ m ® /•■f 



pinnate. The narrow dark- / 1 ^ ^^S^s <t IM 



coloured scales are distinctive. /'/^ /fe? ^'"""'"'''^ ^ \k\ 



The sterile leaves are spreading //ssstk ^^ ^B^ V--:>\ 



and the venation open. The // (| 5 ^ Wr-----'-<\ 



sporophylls are erect, the ( \ a ^ ^1 /^^^ Z— -~0\ 



pinnae narrow, and the reflexed Vv" W^ """ ^1^'^ *^ ^^^^ 



indusioid margin dark brown. ^'"^^^^V lil (^ ^ ® B 



The vascular structure of the ^<^5k ® <9> M 



axis is dictyostelic with a mass- ^xN^ ^.,--<^!^^^ ^m ^ /v 



ive pith (Fig. 689). Following ^vv;v^^->^■'^ ^<^v_^,--0^ 



the succession of the leaf-traces Y^g. 689. Transverse section of the stock of Blahmcm 



as numbered from below, it is tabtdare (Thunbg.) Kuhn. The numbers indicate the suc- 



, u u C \^ cessive leaf-gaps, from which the leaf-traces arise as two 



seen that at the base 01 each straps, subdividing early to form a horse-shoe curve. ( x 4.) 



