GROUP IV. — PHANEROGAMIA : ANGIOSPERM^. 



509 



Thns, when there are two carpels, the plane of symmetry is generally 

 median because the carpels are frequently median or, less com- 

 monly, lateral {e.g. Vinca minor, Ribes alpinum, Fig. 324 A, B) : 

 but when the two carpels are placed obliquely (e.^/.many Solanaceae, 

 such as Petunia, Fig. 324 D ; Datura, Hyoscyamus : Menyanthes 

 among Gentianacem, Fig. 324 F; Saxifraga), the plane of symmetry 

 is oblique. Similarly, when the gynaeceum is monomerous or 

 trimerous, if it is so situated that its plane of symmetry coincides 

 with the median plane of the flower (e.g. with monomerous 

 gynaeceum, Mirabilis, Mahonia ; with trimerous gynaeceum, Pole- 



FiG. 324.— Floral diagrams illustrating monosymmetry due to oligomery of the gynse- 

 CBum : A Vinca minor ; B Rihea alpina ; in these the plane of symmetry is median : C Saxi- 

 fraga ; D Petunia ; in these the plane of symmetry is oblique : gl gland : a ft prophylla : 

 E terminal flower of Gentiana vetiia, with median plane of symmetry : F lateral flower of 

 Mtnyanthea trifoliata, with oWique plane of symmetry ; p p prophylla. (After Eichler.) 



monium ; some Caryophyllaceae including most species of Silene, 

 Stellaria, Spergularia, etc.; some Campanulaceae ; JDeutzia crenata; 

 Samhucus Ehulus, etc.), then the plane of symmetry of the flower 

 is the median plane ; but when the plane of symmetry of the 

 gynaeceum is oblique (e.g. with monomerous gynaeceum, Berberis, 

 Anacardium ; with trimerous gynaeceum, some Malpighiaceae, 

 ^sculus) the plane of symmetry of the whole flower is oblique 

 likewise. 



