DICOTYLEDONES. 



Series I. Choripetalae. 



Petals separate and distinct from each other, or wanting. 



The series is also known as Archichlamideae, and comprises 

 most of the families formerly grouped under Apetalae (without 

 petals) and Polypetalae (with separate petals). Exceptions to the 

 typical feature of separate petals are found in the Fabaceae, in 

 which the two lower petals are more or less united; in the 

 Fumariaceae, where the two inner petals or all four of them are 

 sometimes coherent ; in some Crassulaceae ; the Polygalaceae, in 

 which the three petals are united with each other, and with the 

 stamens ; Oxalidaceae and Ilicaceae, whose five petals are sometimes 

 joined at the base. 



t Petals none (except in family Portulacaceae and in most Caryophyllaceae, 

 which are herbs with the leaves nearly always opposite, the seeds with endosperm). 



Calyx none (except in some of the SANTALAI/ES, and sometimes 

 Loosely jointed trees, the leaves reduced to verticillate scales 



Order 1. 

 Plants not loosely jointed ; leaves normal. 



Herbs with small perfect flowers in spikes. Order 2. 



Trees or shrubs ; staminate flowers, and some- 

 times also the pistillate, in aments. 



Leaves simple. Order 3. 



Leaves odd-pinnate or trifoliolate ; fruit a 



nut enclosed in a husk, or drupe-like. Order 4. 



Calyx present. 



Flowers monoecious, dioecious or polygamous, 



ovary superior, 1-celled. 

 Flowers dioecious or perfect ; ovary inferior, at 



least in part. 

 Ovary 1-celled. 

 Ovary several-celled (usually excelled) ; flowers 



perfect. 

 Flowers mostly perfect ; ovary superior. 



Embryo straight or nearly so; fruit an achene. Order 8 

 Embryo coiled, curved or annular ; fruit not 

 an achene. 



in Casuarinaceae). 

 CASUARINALES. 

 PIPERALES. 



MYRICALES. 

 JUGLANDALES. 



Order 5. URTICALE.S. 



Order 6. 

 Order 7. 



Order 9. 



SANTALALES. 

 ARISTOLOCHIALES. 

 POLYGONALES. 

 CHENOPODIALES. 



$$ Petals present (wanting in Ceratophyllaceae, aquatic herbs with whorled 

 dissected leaves ; in many Ranunculaceae ; in Lauraceae, alternate-leaved aromatic 

 trees and shrubs ; in Zanthoxylum, pinnate-leaved trees of the Rutaceae ; in many 

 Euphorbiaceae ; in some species of Ludivigia in Onagraceae ; in Proserpinaca of the 

 Haloragidaceae). 



A. Ovary superior, free from the calyx (partly or wholly inferior in Loasaceae). 



Carpels solitary, or several and distinct (united in some Nymphaeaceae) ; sta- 

 mens mostly hypogynous and more numerous than the sepals ; sepals mostly 

 distinct. Order 10. RANALES. 



Carpels 2 or more, united into a compound ovary ; 



stamens hypogynous; sepals mostly distinct. Order 11. PAPAVERALES. 



Carpels solitary, or several and distinct, or some- 



times united ; stamens mostly perigynous or epi- 

 gynous ; sepals mainly united or confluent with 

 the concave receptacle (hypanthium). 

 Carpels united into a compound ovary ; sepals 



mostly distinct. 

 Stamens few, rarely more than twice as many 



as the petals. 



Stamens as many as the sepals or fewer 

 and opposite them, or more numerous. 

 Ovules pendulous, the raphe toward the 



axis of the ovary. 



Ovules pendulous, the raphe away from 

 the axis of the ovary, or erect, or as- 

 cending. 



Stamens as many as the sepals and alter- 

 nate with them, opposite the petals when 

 these are present ; ovules erect. 

 Stamens usually very numerous (except in 

 Violaceae and Passifloraceae) ; disc in- 

 conspicuous, or none. 



Order 12. ROSALES. 



Order 13. GERANIALES. 



Order 14. SAPIKDALES. 



Order 15. RHAMNALES. 



