526 INTRODUCTION TO CRYPTOGAMIC BOTANY. 



as in 0. regalis, they are collected at regular distances into 

 little opposite fascicles, instead of being equally distributed 

 along the costa. These form the genus Planesium of PresL, a 

 fact first pointed out by Mr. J. Smith. 



3. ScHiz^ACEiE, Presl. 



SchiZjEE^, Mart, Endl., Lindl. 



Sporangia oblong, furnished with an imperfect ring at the 

 apex, bursting longitudinally, arranged in imbricated spikes, 

 or on resupinate divisions of the frond. 



593. In OsmundacecB the ring was represented by a disc of 

 hexagonal cells ; in Schizceacece there is a single series only of 

 cells, forming a spurious horizontal ring at the apex (Fig. 114, 

 a, h). There are two distinct forms assumed by the fruit. 

 The sporangia are either disposed at the back of the frond, on 

 imbricated spikes, formed from a transformation of the ulti- 

 mate pinnae ; or in other cases they appear, from the resu- 

 pination of the fruit-bearing spikes, to be seated on the upper 

 side, though in reality on the lower. In the former series we 

 have ferns remarkable for their climbing habit. Lygodium 

 articulatum,, for instance, in New Zealand, ascends trees 50 

 or ] 00 feet high, and its tough, wiry stems are used for cord- 

 age. These are, for the most part, confined to tropical coun- 

 tries. Lygodium palmatwm, however, occurs in New England 

 and Pennsylvania. Aneimia approaches in habit to Osmunda, 

 especially in those species which have the fertile fronds par- 

 tially transformed. From either a genus is separated on 

 account of the reticulate veins, Aneimidictyon and Lygodic- 

 tyon. The Brazilian Trochopteris is remarkable for its sub- 

 orbicular lobed frond, the lower lobes of which bear the 

 sporangia. In other respects it is an Aneimia. Mohria has 

 the sporangia seated near the margin of the frond. In 

 Schizma the frond is either dichotomous, palmate, or flabelli- 

 form, according to the degree in which the divisions are 

 laterally united or separated, the same species exhibiting an 

 entire or highly divided frond. As the pinnate spikelets ter- 

 minate the lobes, we have either a frond fringed with spikelets 

 or exhibiting as many as there are divisions. In Actinostachys 

 the fertile lacinias are digitate instead of pinnate, and the 



