206 



SYSTEMATIC BOTANY. 



Affinities, &c. The typical floral formula is S 2 P 4 c\D A oo Gr 2. Taking 

 the common Poppies as types of this order, we find a marked distinction from 

 Banunculaceae in the 2-merous calyx, the confluent carpels, and the milky 

 juice ; but the first two of these characters do not hold universally, since 

 Argemone has sometimes 3 sepals, and Plati/stemon has the carpels more 

 or less distinct, or united only slightly externally. Bocconia, with small 

 flowers and no petals, approaches to Thalictrum ; it has but a single 

 carpel. Monstrous capsules of Papaver occur in gardens with the carpels 

 partly free, somewhat as in Nigella. This Order is also related to the 

 Nymphaeaceae by the general structure of the flower of Papaver ; and the 

 dissepiments extend quite to the axis in the Calif ornian genus Romneya. 



Fig. 344. 



Papaver somniferum. 

 The Opium Poppy. 



Capsule of Poppy (Papaver} : a, transverse section ; 

 b, seed. 



Another genus from the same region, Dendromecon, has peculiar double- 

 lined parietal placentas, and the capsule bursts into 2 valves with the 

 seeds on the margins, as in Cistaceae. The quaternary arrangement of 

 the floral envelopes and the pod-shaped ovary of EsclisJioltzia, Glmtcmm, 

 Chelidonium, c. cause a close resemblance to Cruciferae and Capparidacere, 

 from which, however, there is a marked distinction in the perispermic 

 seeds and the narcotic milky juice. The tetradynamous stamens of 

 Cruciferae, too, almost always afford a striking character ; but a remark- 

 able exception is supplied by an East-Indian polyandrous Crucifer 

 (Meaacarptea polyanara), whose stamens are numerous like those of a 

 Poppy. The nearest relatives of the Papaveracese are the Fumariaceas, 



