12 Flora of the Paloasc Region 



which the seeds are ripened: stigmas present: cotyledons one or 

 two, very rarely wanting: perianth present or wanting. 



Sub-class r. MONOCOTYLEDONES. 



Embryo of the seed with but a single cotyledon , that is with the 

 first leaves of the germinating plantlet alternate: stem composed 

 of a mass of soft tissue in which bundles of wood cells are irreg- 

 ularly imbedded: no distinction into bark, wood and pith: leaves 

 usually parallel-veined, mostly alternate and entire, commonly 

 sheathing the stem at the base and often with no distinction of 

 blade and petiole: parts of flowers mostly in threes. 



Family 9. TYPHACEAE. 



Marsh or aquatic herbs with creeping rootstocks and linear flat 

 sheathing leaves: stems erect, terete: flowers monoecious, densely 

 crowded in terminal spikes which are subtended by spathaceous 

 bracts: ovary one, 1-2-celled, with as many persistent styles: fruit 

 nutlike; endosperm copious. 



19. TYPHA. 



Flowers in a dense cylindrical spike; staminate and pistillate 

 portions of spike either contiguous or separate: stamens with very 

 short connate filaments, mixed with numerous long hairs: ovary 

 long-stalked, one-celled, surrounded by numerous bristles and 

 rudimentary ovaries: fruit minute, usually splitting on one side. 



T. latifolia L. Stout, 1-3 m. tall: leaves flat, sheathing at base, 1-2 cm. 

 wide: pistillate and staminate portions of the spike close together, each 8-30 

 cm. long; the pistillate dark brown: stigmas rhombic-spatulate: pollen grains 

 in fours. In shallow water, not rare. 



Family 10. NAIADACEAE. 



Immersed aquatic plants with slender often branching leafy 

 stems: leaves flat or filiform: flowers spicate, perfect (in ours): 

 perianth usually of four herbaceous segments: stamens 1-4, 

 occasionally more, distinct, hypogj'nous: ovaries 1-9, mostly dis- 

 tinct, 1 -celled, mostly i-ovuled: seeds straight or curved; endosperm 

 none. 



Flowers perfect. 20. potamogktox. 



Flowers monoecious or dioecious. 21. NAIAS. 



20. POTAMOGETON. 



Leaves alternate or the uppermost opposite, often of two kinds; 

 the submersed mostly linear; the floating lanceolate, ovate or oval: 

 spathes enclosing the young buds usually perishing soon after 



