Flora of the Palousc Rcgio?i in 



ANALYTICAL KEYS TO THE FAMILIES. 



Plants vascular, reproducing by spores. Branch PTERinoPHYTA 



Plants vascular, reproducing by seeds. Branch spermatophyTa 



Branch PTKRIUOPHYTA. 



Leaves few, large: steins solid, mostly underground. 

 Sporangia borne within the tissue of the leaf. 



Sporangia in a prominent and distinct fertile lobe of the leaf: spores 



of one kind. ophioglossaceae i 



Sporangia in the enlarged bases of the leaves: spores of two kinds. 



ISOETACEAE 2 



Sporangia formed of modified hairs or outgrowths from the surface of 

 the leaf. 

 Sporangia in groupsonthe back of foliage leaves: sporesof one kind. 



POLYPODIACEAE 2 



Sporangia in a closed receptacle formed by the folding back and 



fusion of the edges of a modified leaf: spores of two kinds, 



in the same receptacle. marsiliaceae 5 



Leaves minute, whorled: stems hollow, jointed. EQUISETaceae 6 



Leaves small, scattered, numerous: stems solid. SELAGINELLACF.ae 7 



Branch SPERMATOPHYTA. 



Ovules and seeds not in a closed cavity, usually on the face of an open scale- 

 leaf: stigmas none. Class gymxospermae hi 



Ovules and seeds contained in a closed cavity surrounded by one or more 

 closed and modified leaves forming an ovary: stigmas present. 



Class AXGIOSPERMAE III 



Cotyledon one: stem with no distinction into bark, woodand pith (endo- 

 genous): leaves usually parallel-veined: parts of the flower 

 nearly always in threes. Subclass monocotyledones hi 



Cotyledons two: stem (with rare exceptions) of bark, wood and pith 

 (exogenous): leaves usually net-veined: parts of the flower 

 in fours, fives and sixes, never in threes. 



Subclass DICOTYLEDOXES IV 



Class IV. GYMNOSPERMAE. 

 Fruit a cone. pixackae 8 



Fruit drupe-like. taxaceae ii 



Class V. ANGIOSPERMAE.— Subclass i. MONOCOTYI*EDONES. 



Carpels one or more, distinct: parts of flowers mostly unequal in number. 

 Flowers not in the axils of dry chaffy scales (glumes): aquatic or marsh 

 plants. 

 Perianth of bristles or chaffy scales: endosperm mealy or fleshv. 



tvphaceae 12 



Perianth corolla-like or herbaceous or none: endosperm none or 

 very little. 

 Perianth-segments, when present, herbaceous. 



xaiadaceak 12 



Perianth of two series of segments, the outer (sepals) green, the 



inner (petals) mostly white, alismaceae 13 



