68 University of California Publications in Botany [Vol.9 



Ovary compound (= formed of more than a single carpel) ; perianth always 

 present, its segments in 2 series. 

 Ovary superior (i.e., free from the calyx). 



Plant rush-like; perianth segments similar, chaffy, none petaloid. 



Family 12. Juncaceae 

 Plant not rush-like; at least the inner whorl of perianth segments 

 petaloid. Family 13. LiUaceae 



Ovary inferior (i.e., its wall united with the calyx). 



Flowers in umbels, regular; stamens 3. Family 14. Iridaceae 



Flowers in spikes or racemes, irregular; stamen 1. 



Family 15. Orchidaceae 



II. Flowers composed of parts arranged in 4's or 5's, rarely otherwise; leaves 

 with the veins forming a network; stems with central pith and, if per- 

 ennial, showing annual rings. Dicotyledons 

 *Corolla none : calyx absent or present : if present, then herbaceous or petaloid 

 (in CaryophyUaceae, the corolla commonly present). 



Trees and shrubs. 



Flowers in catkins (aments). 



Both staminate and pistillate flowers in catkins. 



Flowers 1 to each scale or bract of the catkin, the ovary developing 

 to a many-seeded, 1-celled pod with comose seeds. 



Family 16. SaHcaceae 



Flowers 2 or 3 to each scale of the catkin; ovary becoming a winged 



nutlet. Family 17. Betulaceae 



Staminate flowers only in catkins; pistillate flowers in an involucre 



becoming an acorn cup or spiny bur. Family 18. Fagaceae 



Flowers not in catkins. 



Leaves alternate, functional; fruit an achene with persistent long 



plumose style. Family (30). Cercooarpus 



Leaves opposite, scale-like; parasitic dwarf shrubs, growing on conifers 



(in ours). Family 19. Loranthaceae 



Herbs, sometimes suffrutescent at base. 

 Ovary superior. 

 Calyx present. 



Pistil 1, its ovary 5-celled; reddish or whitish saprophyte. 



Family (44). Allotropa 

 Pistil 1, its ovary 1-celled. 



Stipules present and forming sheaths about the nodes. 



Family 20. Polygonaceae 

 Stipules absent. 



Flowers involucrate; calyx 6-parted. Family (20). Eriogormm 



Flowers not surrounded by an involucre; calyx and corolla 5- 



parted, or the latter wanting. Family 21. CaryophyUaceae 



Pistils more than 1 and distinct (i.e., each an ovary), forming 



achenes or follicles. Family 24. Ranunculaceae 



Calyx absent (i.e., flowers naked) ; aquatic plant with opposite leaves. 



Family 34. CaUitricliaceae 



Ovary inferior; aquatic plant with whorled leaves. 



Family 40. Haloragidaceae 



