DICKSON I A. 



169 



have their trunks thoroughly watered twice a day; but these copious waterings 

 should gradually decrease as the season advances, and during the winter the 

 trunks should only be kept constantly moist, the heads being slightly shaded 

 during the hottest summer days only. 



Dicksonias of arborescent habit are invariably propagated from their spores, 

 which they produce in great abundance, and which germinate very freely. 

 Those species which are provided mth rhizomes may be increased by the 

 division of those organs, an operation which is best done in March or April ; 

 but when required in large quantities, it is found more advantageous to 

 propagate them from spores in the usual way. 



Principal Species and Varieties. 



D. (Eudicksonia) abrupta — Eu-dick-so'-ni-a ; ab-rup'-ta (abrupt), Bory. 



This stove plant, native of the Bourbon Islands, is thoroughly distinct 

 from all other known species through the simply-pinnate (once-divided) 

 character of its fronds, 1ft. to IJft. long, 4in. to 6in. broad, furnished on 

 both sides of their midrib with sessile (stalkless), spear-shaped leaflets that 

 are scarcely toothed and of a leathery texture. The lower of these leaflets, 

 about oin. long and lin. broad, have their two halves rather unequal, the 

 base of the upper one being truncate (terminating abruptly) and that of 

 the lower one shghtly eared. The fertile leaflets are narrow and acuminate 

 (terminating in a long, slender point), with numerous sori (spore masses) 

 placed along both edges. D. ahrupta is a most peculiar plant, its habit and 

 general appearance being very like that of the well-known Ne-phrolepis 

 davallioides. — Hooker, Species Filicum, i., p. 72. 



D. (Patania) adiantoides — Pat-an'-i-a ; ad-i-ant-6-i'-des (Adiantum-like), 

 Humboldt, Bonpland, and Kuntli. 

 A very strong- growing, stove species, native of Tropical America, its 

 habitat extending from the West Indies southward to Brazil. Its gigantic 

 fronds, which are produced from a creeping rhizome (prostrate stem) and 

 sometimes attain 12ft. m length, are bipinnate (twice divided to the midrib). 

 Their lower leaflets, 1ft. to 2ft. long and 6in. to 12in. broad, have their 

 pinnules (leafits) cut down in the lower part nearly to the midrib ; these 



