THE TASHAITIAN FLOBA. 225 



'the margin or upper surface, propagation usually by lateral budding. Ovary 

 l-oelled, with usually 1 amphitropous ovule. Fruit a minute utricle. 

 The order consists of but two genera. 



LEMJSTA. 



Flowers formed on the margin. Fronds with a descending root-fibre, at least 

 in the peltate species. 



The genus is found throughout the world. The Tasmanian species are 

 cosmopolitan. 



Fronds oblong with a slender stalk, dichotomously 



dividing, often many times ... ... ... ... 1. L. trisulca. 



Fronds oblong, simple 2. L. minor. 



1. L. TEISTJLCA, Linn. Frond oblong, 1-3 lines long, with a slender stalk, often 

 2 or .3 times as long. Young fronds arising, one on each side of the old one, near 

 the base, not separating from the parent frond, and also bearing young fronds 

 upon maturity ; being repeated several times, the plant may extend to several 

 inches. Flower of Tasmanian plant not seen. 



Common in still fresh water ; also in New South Wales, Victoria, South 

 Australia, and Queensland. Fl. Dec. 



I have always found the Tasmanian plant submerged, and have never 

 found it bearing root fibres. Its general habit also differs from the 

 European form. 



2. L. MINOR, Linn. Fronds oblong, about 2 lines diameter, each with a 

 descending root-fibre ; floating, rapidly budding, so as to cover a considerable 



.surface; the fronds separating when mature 



Very common in still water ; also throughout Australia. Fl. Dec. 



Order LXXXIV. NAIADEJE. 



Perianth, when present, of 3-6 inconspicuous scales. Floral structure very 

 varied, hermaphrodite or unisexual. Stamens 6 or fewer, sessile or nearly so. 

 Pistil of 6 or fewer, usually free, carpels, tapering above into the style and 

 bearing 1 ovule, rarely combined. Fruit 1-seeded nuts, or, where the pistil is 

 syncarpous or the carpels many-ovuled, follicular. 



A cosmopolitan, order of very varied forms ; living principally in water, 

 both salt and fresh, but in some instances also in comparatively dry 

 situations. The included genera are often formed into 2 orders — 

 Triglochin, Potamogeton — and a few small genera not represented in 

 Tasmania forming the order Potamees or Juncaginaceee. 



i. Fresh water or terrestrial plants, the flowers 



numerous in spikes ... ... ... ... ii. 



Flowers few or solitary, or, if numerous, the 



plants are marine ... ... ... ... iii. 



ii. Carpels usually 3 ... ... ... ... ... 1. Triglochin. 



Carpels usually 4 ... ... ... ... ... 2. Potamogeton. 



iii. Flowers few or many together ... ... ... iv. 



Flowers solitary .. • ... ... ... ... v. 



iv. Flowers few, on an elongating coiled peduncle... 3. Ruppia. 

 Flowers in numerous spikes, on a common stalk 4. Posidonia. 

 Flowers few, on a flat peduncle, buried in the 



base of a leaf ... ... ... ... ... 5. Zostera. 



T. Leaves filiform, about j inch ... ... ... 7. Lepiloena. 



Leaves spathulate, 1-3 inches ... ... ... 6. Cymodocea. 



Leaves oblong, stalked ... ... ... ... 8. Malophila. 



