Vlll 



THE TASMANIAN FLORA. 



Sub-class — Petaloidej: HYPOGENJi. — 

 continued. 



Order Ixxxiv. 

 Ixxxv. 



Naiadem. 

 AlismacecB. 



Sub-class — G-LUMtFLORiE . 

 Order Ixxxvi. Gentrolepidece^ 



Ixxxvii. 



Ixxxviii. 



Ixxxix. 



Bestiacece. 



Ci/peracecB. 



Graminem. 



GTMNOSPERMS.^Plants in which typical ovules are developed and the 

 gametic generation, though still very rudimentary, is much more defined than in 

 Angiosperms. The ovules are not developed in closed sacks or carpels, but upon 

 the upper surfaces of scale-like bracts, or may appear naked _ and terminal, 

 sometimes more or less enclosed in a fleshy aril, microspores still maintaining 

 the character of pollen and formed in well-developed stamens. Stamens and 

 pistils often massed into cones, but no specialisation of members to form true 

 flowers. 



The Gymnosperms, represented in the present day principally by Conifers, 

 such as Pines, Cypresses, Tews, date back long before the time of Angiosperms, 

 forms occurring as remotely as the Old Eed Sandstone era. And whereas in the 

 present day the Angiosperms contain as varied forms as perhaps they ever did, 

 the Gymnosperms have long passed their prime, which appears to have been in 

 the Mesozoic era. Also, though we have no evidence yet unfolded to demonstrate 

 the descent of the great sub-divisions of the Angiosperms, we have abundant 

 evidence of the close relationship of the Gymnosperms to the ferns through the 

 Heterosporous Lycopods 



Representatives of only two orders ocoar in Tasmania: — 



CupressacecB (Cypresses). Cover scales and ovuliferous scales entirely 

 fused, forming somewhat solid cone scales that usually bear many 

 ovules. 

 TaxacecB (Yews). Ovuliferous scale wanting. ■ Cones never woody, 

 generally succulent. Ovule sometimes solitary and immersed in a 

 fleshy aril. 



PTERYDOPHYTA. — (Fern-tribe). — Plants which do not develop flowers, 

 and whose spore-bearing sacks are either developed in clusters or singly, upon the 

 backs or margins, or sometimes immersed in the tissues of, leaves or at the base or 

 axils of leaves. The spore-bearing leaves similar to the barren leaves, or sometimes 

 greatly specialised, but never assuming the character of cones. Spores in some 

 orders of two kinds, small and large ; the small-spored sacks never assuming the 

 specialised form of stamens, the microspores producing semi-enclosed gamophytic 

 growth, in which are developed antheridia that produce motile gametes ; the 

 large-spored sacks producing megaspores that develop semi-enclosed 

 gamophytic growth, in which is produced archegonia that develop each an 

 ovum. This development of the megaspore differs in little but degree from the 

 development taking place in the Gymnosperms, only in the latter they 

 remain attached to the parent plant, while in the former they are shed from 

 the sporangia before, or soon after, commencing gamophytic development. 

 In other orders the spores are all of one size ; each spore grows into an 

 independent being in the form of a flat, green, thalloid plant or prothallus, 

 from a quarter to a few inches in size, with the essential organs of reproduction, 

 the antheridia and archegonia, developed on the under surface. 



The plants representing the Pterydophyta in our flora are few in number, and 

 varied in structure. They are the remaining representatives of a vast and 

 luxuriant flora that, dating back into early Palseozoic times, reached a 

 marvellously rich development in the later Palseozoic ages, to dwindle down to a 

 comparatively modest rank in the present day. We find accordingly that many 

 present-day forms — little, retiring plants, with apparently no immediate 

 relatives — are the sole surviving descendants of noble and important families. 



