FLOWERING PLANTS AND FERNS OF ARIZONA 57 



29. Leaves simple; stamens less conspicuous than the corolla; flowers 

 not in dense heads or spikes (30). 

 30. Anthers awned or opening by pores or both ; plants shrubs or else 

 saprophytic, without chlorophyll, the leaves reduced to scales; 



corolla urceolate or subglobose 94. Ericaceae. 



30. Anthers not awned, splitting longitudinally; plants suffrutescent, 

 always with chlorophyll and well-developed leaf blades; 



corolla sal verform 96. Plumbaginaceae. 



28. Filaments attached to the corolla (31). 



31. Plants without chlorophyll, parasitic; leaves reduced to scales (32). 

 32. Stems mostly subterranean, thick and succulent, attached to the 

 roots of the host plant; corolla lobes and stamens 6 or more; 

 flowers small, very numerous, crowded on a dilated saucer- 

 shaped receptacle 93. Lennoaceae. 



32. Stems above ground, twining, slender, yellow, attached to the 



stems of the host plant; corolla lobes and stamens not more 

 than 5; flowers in cymose clusters: Genus Cuscuta. 



103. Convolvulaceae. 

 31. Plants with chlorophyll and with well-developed leaf blades (33). 



33. Fruit at maturity separating into 2 to 4 dry nutlets, or by abortion 



only 1 (34). 

 34. Stamens and corolla lobes 5; stems not 4-angled. 



106. BORAGINACEAE. 



34. Stamens 2 or 4, if 4 then in 2 pairs; stems often quadrangular 

 (35). 

 35. Ovary entire or longitudinally grooved, the style apical. 



107. Verbenaceae. 

 35. Ovary 4-lobed, the style rising between the lobes. 



i 108. Labiatae. 



33. Fruit not separating into nutlets (36). 



36. Plants shrubs or small trees, usually thorny or spiny; fruit a 

 drupe containing 1 stone (37). 

 37. Stamens 5, with 5 petaloid staminodia; corolla with a pair of 

 lobelike appendages in each sinus of the 5 true lobes; 

 flowers inconspicuous, in axillary clusters. 



97. Sapotaceae. 



37. Stamens 4; staminodia none; corolla without appendages; 



flowers showy, in terminal headlike clusters: Genus 



Lantana 107. Verbenaceae. 



36. Plants various; fruit not a drupe, if berrylike, then several- 

 seeded (38). 



38. Stamens 10 or more (39). 



39. Plants herbaceous, succulent, with a rosette of relatively 

 large basal leaves, the stem leaves bractlike, persistent; 

 carpels normally 5, separate or nearly so: Genus 

 Echeveria 49. Crassulaceae. 



39. Plant a thorny shrub with long whiplike branches; stem 



leaves not bractlike, soon deciduous; carpels 3, united. 



79. FOUQUIERIACEAE. 



38. Stamens fewer than 10, seldom more than 5 (40). 



40. Fruit a samara with the wing mostly terminal, or a didy- 



mous capsule; stamens 2 or 4 98. Oleaceae. 



40. Fruit not a samara or a didymous capsule (41). 



41. Ovaries 2, united only by the common style or stigma; 

 fruit a pair of elongate follicles; seeds often comose. 



101. Apocynaceae. 



41. Ovary 1, sometimes deeply parted; fruit a single capsule 



or berry; seeds not comose (42). 



42. Ovary 1-celled or sometimes imperfectly 2-celled by 



introflexion of the placentae (43). 



43. Stamens opposite the corolla lobes; style 1; stigma 



entire 95. Primvlaceae. 



43. Stamens alternate with the corolla lobes (44). 



44. Style 1 and entire, or none; stigma 1, more or less 

 distinctly 2-lobed or bilamellate, or the stig- 

 mas 2; plants mostly glabrous; leaf blades 

 entire; inflorescerce not scorpioid. 



100. Gentiaxaceae. 



