FERNS OF THE MALAY-ASIATIC REGION. 6 



1. OPHIOGLOSSACE^E. 



Rhizome usually underground, small, usually erect, of very slow growth, 

 producing one or two leaves annually; fronds small or of moderate size, 

 without stipules, straight or folded in vernation (not circinate) ; fertile 

 segment very contracted, springing from the ventral face of the sterile 

 frond or of its stipe; sporangia large, formed each from a group of 

 superficial cells and having a wall several layers of cells thick, without 

 any annulus. 



A small family of three genera. These are perhaps the most primitive living 

 Pteridophyta. The origin of the sporangium, the vernation, and the structure 

 of the stomata recall Anthoeeros; and these characters and the occurrence of 

 collateral bundles with secondary thickening indicate a close affinity to what must 

 have been the ancestors of the flowering plants. 



Veins reticulate 1- Ophioglossum 



Veins free: 



Sterile segment pinnate in plan..- 2. Bolrychium 



Sterile segment trifid, its divisions sparingly pinnate 3. Helminthostachys 



1. OPHIOGLOSSUM Linnaeus. 



Sterile segment entire or sparingly forked, with anastomosing veins; 

 fertile segment likewise simple or rarely forked, fleshy, linear; sporangia 

 immersed in the sides of the segment and opening by a slit transverse 

 to it. A genus of at most 43 known species, chiefly tropical. 



Fertile and sterile segments separating at or below the base of sterile blade. 



Sterile blade with an apparently stout midrib L O.fibrosum 



Without apparently stout midrib. 

 Sterile blade linear or lanceolate. 



Segments separating well above ground 2. 0. gramincum 



Common stipe hardly reaching above ground. 



Fertile segment rising from base of sterile... 3. 0. japonicum 



Sterile segment stalked 4. 0. braunii 



Sterile blade ovate or elliptic. 



Base cuneate or truncate 5. 0. pcdunculosum 



Base cordate 8. 0. reticulatum 



Sterile blade obovate 7. 0. obovatnm 



Fertile segment rising from sterile blade. 



Terrestrial 8. 0. intermedium 



Epiphytic - &• 0. pendulum 



Sterile blade practically none 10. 0. simplex 



1. Ophioglossum fibrosum Schum. 



Ehizome large and globose with numerous fibrous roots; common stipe 

 very short; sterile segment 4 to 5 cm long, lanceolate or oblong, acute 

 or obtuse, thick and opaque; venation very dense next the costa, giving 

 the appearance of a broad midrib; fertile segment 3 to 5 cm long, on a 

 stipe of 10 to 12 cm; sporangia up to 50 on a side. 



Southern India, Sumatra, tropical Africa. 



