40 



THE FLORIST. 



In the first group (1), with sori transverse to the veins, parallel 

 with the costa or margin, it is to be remarked, that in the few cases 

 where the fronds have no veins, the plants may be recognised as 

 belonging here, by the circumstance of the sori being parallel with the 

 midrib. The sorus is usually linear or considerably elongated, but it is 

 occasionally oblong or lunately curved, or, in one or two groups, sometimes 

 punctiform. In the first of these exceptional conditions, the fact of its 

 having the same general direction as the costa or margin indicates at 

 once the group to which it belongs ; and in the second, the sori being 

 marginal with a transverse indusium, there is no difficulty in ascer- 

 taining that they belong to the type of structure in which the sorus is 

 transverse to the veins. 



Irrespective of these somewhat aberrant and exceptional forms, which, 

 however, rightly viewed, find their place in the series without difficulty, 

 the group now before us is again divided into three parts, by means 

 of secondary characters derived from the receptacles. These characters 

 are found in the form of the receptacle, which is linear, oblong, trans- 

 versely-arcuate, or rarely punctiform, or in its position with respect to 

 the midrib or margin. In this way we mark out three groups of 

 moderate extent, as follows : — 



Sori transverse to the veins, &c. 



(a) Receptacles linear or oblong, costal or subcostal (often at the same time 

 submarginal by the contraction of the frond) . 



(6). Receptacles linear (sometimes oblong or punctiform) marginal or sub- 

 marginal (rarely medial), always remote from the costa. 



(c) . Receptacles short arcuately-transverse on the venules, subparallel with 

 the costa or margin. 



The first group (a) with linear costal receptacles embraces two 

 sections, as follows : — 



(a). Receptacles costal, &c. 



Sori indusiate linear superficial . . . §3. Lomariece. 

 Sori nonindusiate, linear or oblong, superficial or 

 immersed §4. Pleurogrammece. 



The Lomariece consist of four genera, whose common character is 



the continuous line of spore- 

 cases situated near to the 

 costa, and furnished with 

 an indusium. Of these 

 Lomaria and Blechnum 

 have the veins free ; and 

 Salpichkena and Sadleria 

 have them combined. 

 Neither of the latter genera 

 are in cultivation, but they 

 are interesting, the first as 

 being scandent, and the 

 second arborescent. 



The Pleurogrammece 



(a) Lomaria callosa ; (4) Blechnum differ obviously fl'Om the 



onentaie. Lomariece in wanting an 



indusium, while they agree with them in the costal line of spore-cases. 



