47© FOURTH GROUP.— SEED- PLANTS. 



alternating with the petals (Celastreae, Ilicineae, etc.) or opposite them (Ampehdeae, 

 Rhamneae), very rarely with two staminal whorls. 



Families : i. Celastreae, 5. Ilicineae, 



2. Olacineae, 6. Ampelideae, 



3. Hippocrateae, 7. Rhamneae. 



4. Pittosporeae, 



V. Tricoccae. 



Flowers with calyx and corolla or naked (Caliitrichaceae) ; stamens one (Callitri- 

 chaceae) or more; ovary of three carpels (Euphorbiaceae) or two (Caliitrichaceae), 

 superior ; seeds with endosperm. Monoecious. 



Families : i. Euphorbiaceae, 3. Buxeae, 



2. Caliitrichaceae, 4. Empetreae. 



VI. Calyciflorae. 



Calyx, corolla and androecium with perigynous or epigynous insertion Cexcept in 

 Saxifragineae and Rosiflorae) ; the greater part of the families in this group have 

 the perianth differentiated into calyx and corolla, but there are several exceptions ; 

 flowers almost without exception cycHc (except in Cactaceae and in the androecium of 

 Begoniaceae) ; androecium isostemonous, diplostemonous or obdiplostemonous (in 

 the Rosaceae frequently more than two staminal whorls with the number of parts 

 other than in calyx and corolla) ; carpels usually united, free in Crassulaceae, 

 Rosaceae, etc. 



Order i. Umbelliflorae : Ovary inferior, calyx often rudimentary, androecium 

 isomerous with the corolla and alternating with it ; a nectariferous disk between the 

 stamens and style. 



Families : i. Umbelliferae, 2. Araliaceae, 3. Cornaceae. 



Order 2. Saxifragineae : Calyx always developed, corolla often imperfectly 

 developed or suppressed ; stamens usually in two whorls, with hypogynous (Francoeae, 

 Ribesieae), perigynous or epigynous insertion ; carpels isomerous with the preceding 

 whorls or reduced to two. 



Families : i. Saxifrageae (with Parnassieae), 5. Escallonieae, 



2. Francoeae, 6. Cunonieae, 



3. Hydrangeae, 7. Ribesieae (Grossularieae), 



4. Philadelpheae, 8. Crassulaceae. 



Order 3. Opuntieae : Fleshy succulent plants usually without leaves ; sepals 

 and petals many, usually arranged spirally and not sharply distinguished from one 

 another ; anthers numerous ; ovary inferior. 



Family : Cactaceae. 

 Order 4. Passiflorineae : Flowers usually regular, insertion of stamens epigynous 

 or perigynous ; ovary of three carpels with parietal placentas, of more than one cell in 

 Begoniaceae ; it is doubtful whether Datisceae and Begoniaceae belong to this order. 

 Families : I. Samydaceae, 4. Loaseae, 



2. Passifloraceae, 5. Datisceae, 



3. Turneraceae, 6. Begoniaceae. 



Order 5. Myrtiflorae : Flowers tetramerous regular ; anthers in two whorls 

 or by branching very numerous as in Myrtaceae ; ovary syncarpous with complete 



