KEY TO THE NATUBAL ORDERS. 



Calyx of 5 united sepals; flowers very small: petals and 



stamens 5; stamens and pistil on separate flowers , Ixix. Euphorbiacece. 



Calyx of 2 or 4 free sepals 17. 



16. Leaves orbicular, divided into 3 leaflets, or much divided ; 



stamens 10 xx. Oeraniacem. 



Leaves linear; stamens 5 xviii. LiTiacece. 



Leaves variously shaped, covered with long-stalked 



sticky glands; stamens 5 xxix. Droseracece. 



17. Sepals 4; petals 4; stamens 6, but soinetimes some im- 



perfect V. CrucifercE. 



Sepals 2; petals 5; stamens 6 to 8 xii. Portulaccacece. 



18. Floral tube long and free round the ovary ; petals in- 



serted at its mouth xxxii. Lythracem. 



Calyx-lobes inserted above the ovary 19. 



19. Ovary distinctly formed of two 1-seeded carpels; sepals, 



petals, and stamens 5 xxxvi. UmbellifercE. 



Carpels indistinct, many-seeded; sepals and petals 5; 



stamens 2; plant densely tufted; moss-like xli. Stylidiacece. 



Sepals and petals 4; stamens 8 20. 



:20. Flowers small, green, obscure; plant usually rough; 



ovary short, with four 1-seeded cells xxx. Haloragea. 



Flowers usually conspicuous; ovary linear; seeds very 



numerous, with a tuft of hairs at one end xxxiii. Onagracece. 



:21. Corolla nearly regular, with 5 spreading petals 22. 



Corolla very ii:re^ular; petals partially enclosing the 

 stamens and pistil 23. 



22. Stamens 5; ovary in 2 parts; calyx-lobes and petals in- 

 serted above the ovary xxxvi. Umbelliferce. 



Stamens 10 ; ovary in 5 parts ; calyx and corolla distinctly 

 irregular xx. Geraniacece. 



"23. Upper petal much larger than and outside the rest; 



stamens 10; fruit 2-valved xxv. Leguminosce. 



Upper pair of petals rather shorter than the rest, and 



recurved; stamens 5; fruit 3-valved vi. Violacem. 



24,. Corolla regular 25. 



Corolla irregular, sometimes appearing regular, but split 

 on one side , 35. 



25. Corolla inserted below or nearly below the ovary 26. 



Corolla arising above the ovary, or scarious, and closely 

 enclosing it 33. 



:26. Pistil of 2 to 5 free or nearly free 1-ovuled parts 27. 



Pistil entire or lobed 28. 



27. Flowers in an erect spike, or solitary in the leaf axils ; 



stamens not inserted on the corolla xxii. Stackhousiacece. 



Flowers in a one-sided coiled raceme ; stamens inserted 

 on the corolla '.. ... lii. Boraginaceoe. 



'28. Stamens '2 or 4; corolla never quite regular, often 



divided nearly to the base Iv. Serophulariacece, 



Stamens 6; corolla quite regular, deeply or slightly 

 divided 29. 



29. Petals united only at the extreme base ; flowers white 



or pink 30. 



Petals with a distinct tubular base, often entirely united. 31. 



30. Flowers numerous, in one-sided coiled spikes; styles 5 ... xlvi. Plumbaginaeece. 

 Flowers few, in erect racemes or cymes; 5 filiform pro- 



•cesses alternate with the stamens; style single xlvii. PrimidacecB. 



31. Flowers yellow ... li. Gentianacem. 



Flowers white, pink, or blue 32 



.'32. Flowers few together, on lateral or terminal peduncles 

 that are never axillairy ; anthers erect round the style, 



opening by terminal pores liy. Solanacem. 



Flowers axillary, usually solitary; stamens spreading ... liii. OonvolvulacecB. 



