WOOTON AND STANDLEY—FLORA OF NEW MEXICO. 13 
Subclass 1. MONOCOTYLEDONES. 
KEY TO THE ORDERS. 
Perianth when present rudimentary or degenerate, often composed of bristles or mere 
scales, not corolla-like, sometimes wanting. 
Flowers in the axils of dry or chaffy, usually imbricated, bracts (scales or glumes), 
10. POALES (p. 42). 
Flowers not in the axils of dry or chaffy bracts. 
Perianth of bristles or chaffy scales............... 7. PANDANALES (p. 39). 
Perianth fleshy or herbaceous, or wanting. 
Fruit baccate; endosperm present; plants 1 cm. broad or less, consisting 
merely of a flat thallus with 1 or more roots, floating. 
11. ARALES (p. 124). 
Fruit drupaceous; endosperm wanting; aquatics with well-developed 
StOMS....2.ceceeeeeeeeeeeeceeececeeeees 8. NAIADALES (p. 39). 
Perianth of 2 distinct series, the inner usually corolla-like. 
Gyneecium of distinct carpels...............2202202 22 eee 9. ALISMALES (p. 41). 
Gyneecium of united carpels, 
Endosperm mealy........--+--ee-eeeeeeeeeeeeee 12. XYRIDALES (p. 125). 
Endosperm fleshy, horny, or cartilaginous. 
Ovary and fruit superior................20-206- 18. LILIALES (p. 127). 
Ovary and fruit wholly or half inferior. ; 
Endosperm present; flowers regular.14. AMARYLLIDALES (p. 145). 
Endosperm wanting; flowers irregular..15. ORCHIDALES (p. 148). 
Subclass 2. DICOTYLEDONES. 
KEY TO THE ORDERS. 
Corolla wanting. 
Calyx wanting. 
Herbs. 
Flowers moneecious or dicecious........30. EUPHORBIALES (p. 392). 
Flowers mainly perfect. 
Flowers spicate; styles wanting.......... 16. PIPERALES (p. 154). 
Flowers axillary; styles present. 
(Callitrichaceae) 30. EUPHORBIALES (p. 392). 
Trees or shrubs. 
Fruit many-seeded; seeds each with a tuft of hairs. 
17. SALICALES (p. 154). 
Fruit 1-seeded; seeds without tufts of hairs ...... 42, OLEALES (p. 495). 
Calyx present, at least in the staminate or in the perfect flowers. 
Flowers, at least the staminate, in aments or ament-like spikes; fruit a 
nut or achene; trees or shrubs. 
Leaves simple; ovule pendulous and anatropous.19. FAGALES (p. 163). 
Leaves pinnate; ovule erect and orthotropous. 
18. JUGLANDALES (p. 161). 
Flowers, at least the staminate, not in aments; fruit various; herbs, trees, or 
shrubs. 
Ovary inferior. 
Flowers, at least the staminate, in involucrate heads. 
(Ambrosiaceae) 50. ASTERALES (p. 618). 
