614 PART III. THE CLASSIFICATION OF PLANTS. 



Impatiens Noli-me-tavgere, the yellow Wild Balsam, occurs in damp and 

 shady spots; the ripe fruit flies open with violence at a touch. Impatiens 

 Balsamina, an Indian species, is cultivated. 



Order 6. TROP^OLACEiE. Disc 0: flowers irregular, asym- 

 metric (Fig. 328 B, p. 513); formula Kb, C5, ^4 + 4, 6^'^: the 

 posterior sepal is prolonged into a spur ; the three anterior petals 

 are clawed and ciliate : the two median stamens, one belonging to 

 each whorl, are suppressed, so that there are eight instead of ten : 

 one ovule in each of the three loculi of the ovary : seed without 

 endosperm. Herbs, with exstipulate leaves ; often petiole-climbers. 



TropcBolum majus and minus, Indian Cress, often wrongly termed Nasturtium, 

 are universally cultivated. 



Order 7. Zygophyllace^. Disc annular, fleshy: flowers acti- 

 nomorphic, 5 or 4-merous. Herbs or shrubs with decussate, fre- 

 quently paripinnate, stipulate leaves : seeds with endosperm. 



Lignum Vitce is the wood of Guiacum officinale (West Indies). 



Order 8. Rutace^. Disc usually annular : flowers usually acti- 

 nomorphic and obdiplostemonous : gynaeceum sometimes partially 

 apocarpous, but the styles are usually connate: seed with or without 

 endosperm. There are numerous oil-glands on the leaves and stems. 



Sub-order 1. RuTEiE. The placentte project into the loculi of the ovary ; 



each bears 3 or more ovules : fruit a loculicidal capsule : seed with endosperm. 



Ruta gravcolens, the Rue, has pentamerous terminal 



flowers, and tetramerous lateral flowers. Dictamnus 



Fraxinella has an irregular dortsiventral flower. 



Sub-order 2. Diosme^. Ovules 2 in each loculus : 

 leaves simple : seed without endosperm. 

 Barosma, Agathosma, Empleurum. 

 Sub-order 3. Zanthoxyle^. Flowers usually dioe- 

 cious and polygamous : endosperm usually present. 

 Zantlwxylum fraxineum, from North America, is a 

 Fig. 415.— Diagram of the shrub which is sometimes cultivated. 



flower of Dictamnus. Sub-order 4. ToDDALiEiE. Gymeceum syncarpous : 



fruit iodebiscent, winged, dry or succulent : seed with endosperm. 

 Ptelea trifoliata is a North American shrub with white flowers. 

 Sub-order 5. Aurantib^. GynaBceum syncarpous : calyx gamosepalous : 

 seed without endosperm. 



The genus Citrus has an indefinite number of bundles of connate stamens 

 (polyadelphous) (Fig. 416 A), all belonging apparently to the antisepalous inner 

 whorl : the carpels are usually more numerous than the petals, and during 

 ripening they become filled with a succulent tissue derived from their walls ; 

 the various parts of the flower and the fruit (p, 532) contain much ethereal oil : 



