Civ. GENERA OF KEENS : 



for the most part easily recognised at sight, is known among the 

 Cyathea by its half cup-shaped involucres, combined with the 

 arcuately-anastomosed basal venules. In one species, indeed, H. 

 speciosa, and in those nearly related forms which some botanists 

 regard as distinct from it, the arcuately-anastomosed venules are 

 only now and then produced, and are frequently entirely wanting 

 in those portions of fronds which form herbarium specimens. 

 These we must consider as aberrant species, too closely allied by 

 their external aspect to admit of their being removed from the 

 genus ; their association with which, is moreover justified by 

 the occasional occurrence of the arcuate veins, to be observed 

 in the cultivated pknts. 



Cnemidaria. Arcuate veins always apparent. 

 Ex. : H. obtusa, Klfg. I H. grandifolia, Spr. 



H. horrida, S. Sr. H. Imrayana, Hook. 



H. subincisa, Kze. \ H. marginalia, J. Sm. 



Eleutheria. Arcuate veins rare, sometimes wanting. 

 Ex. : H. speciosa, Klfs. | H. Lindenii, Hook. 



* * Veins always free. 



147. AMPHICOSMIA, Gardner, Hoolc. Land. Journ. 

 Sot. i. 441. 



HTMENOSTBGIA, J. Smith, in part ; ALSOPHII.S sp., Auct. ; HEMITELIJB 

 sp., Auet.; [Cf^iHSjR sp., Auct.; POLTPODII sp., Auct.; ASPIDII sp., 

 Auct. 



Sori involucrate, globose ; the receptacles globose or sub-pyra- 

 midal, medial or axillary. Involucre dimidiate i.e. semicalyci- 

 form with the anterior side deficient becoming reflexed, or rarely 

 forming a small shallow cup-like scale buried beneath the spore- 

 cases. Veins forked or pinnate, from a central costa ; venules 

 free. 



Fronds large, herbaceo- coriaceous, pinnate or decompound. 

 Trunk or caudex arborescent. This group has the hemitelioid 

 involucre, combined with constantly free veins. 



Hymenostegia. Sori medial on the veins. 



Ex. : A. multiflora, Gardu. \ A. capensis (Polypodium, Lin .) 



A.Hostmanni(Hemitelia,Hfc.) | A. laevis (Alsophila, J. SmJ 

 ? A. alternans (Polypodium, Wall.) 

 Chlamydia. Sori axillary at the forks of the veins. 

 Ex. : A. Walkers (Cyathea, Hk J \ A. Beyrichiana (Cyathea, PretlJ 



