409 



THE GENUS THEROSPH/ERA, 



Arch, in Hook. Kew Journ , ii, 52, pro parte. 



I. HISTORICAL. 



This genus, established by Archer in Hooker's Journal of Botany in 1850, 

 is limited to two species which occur, one on the mainland and one in Tasmania, — 

 where it was originally found by Gunn on the mountains near Lake St. C air, 

 whilst in the former it grows on the Blue Mountains west of Sydney. It is closely 

 alhed to Dacrydium. 



II. SYSTEMATIC. 



They are small, low-growing shrubs, occurring generally under shelving rocks 

 at the base of waterfalls. 



The leaves are small, decussate, spirally imbricate, and the flowers dioecious. 

 Male amentum ovoid, globular, terminal, microsporophylls few, spirally arranged, 

 subsessile, the incurved apex narrower than the anther ; the microsporangia 

 parallel, opening outwards in two cells. The female amentum ovate, the macro- 

 sporophylls being spirally arranged, imbricate, and bearing at the base of each an 

 individual erect macrosporangium. 



The fruit cones are ovoid, with concave scales thickened at the base. 



Seed ovoid-oblong, "contracted into a neck and crenulate at the orifice, and 

 occasionally longitudinally winged. 



1. Phcrosplia2ra Hookcriana, 



Archer in Hook. Kew Journ., ii, p. 52; Hook. f. Tas. 1, 355, t. 99. 



Habitat. 



This densely branched shrub is restricted in its distribution to the alpine 

 regions of Tasmania, where it has been recorded from the mountains near Lake 

 St. Clair {Gunn) ; and the high alpine flats of Mount Field East [F. Mueller). 



