A Reversionary Character in the Stock (Matthiola 
incana) and its Significance in regard to the 
Structure and Evolution of the Gynoecium in the 
Rhoeadales, the Orchidaceae, and other Families. 
BY 
EDITH R. SAUNDERS, 
Felloiv of Newnham College, Cambridge. 
With sixty Figures in the Text. 
Contents. 
1. Introduction. The Cruciferous gynoecium ......... 
2. Appearance and structure of a typical siliqua in the Stock ....... 
3. Interpretation of the siliqua construction .......... 
4. Exceptional forms of siliqua in the Stock .......... 
5. Conclusions that the typical siliqua is the outcome of a process of reduction and consolidation, 
and that the formula should he G4, the carpels being dimorphic ..... 
6. The conception of the dimorphic carpel removes the anomaly of the false partition and the 
PAGE 
451 
45 2 
455 
457 
460 
commissural stigma, and brings into harmony and renders 
intelligible 
many 
facts 
hitherto unexplained or without significance ........ . 463 
Reduction and consolidation shown to have occurred in like manner in the Papaveraceae, 
Fumariaceae, Capparidaceae, and Resedaceae ........ 469 
A cursory survey of the Ericales, certain Malvaceae, and some isolated genera which are held 
to have commissural stigmas, leads to the same conclusion. 1 The commissural stigma 
also not a reality in the Orchidaceae, the gynoecium being composed of six carpels 
(G3+3) • • • • • • • • • • • • • • -475 
Summary of Conclusions ............. 478 
1. Introduction. The Cruciferous gynoecium. 
T HE composition of the Cruciferous gynoecium has been the subject of 
much discussion in the past, the chief points at issue being the real 
number of the carpels and the nature of the replum. My attention was 
originally directed to this question in consequence of the repeated appear¬ 
ance in the Stock of fruits of unusual shapes. Some were found with 
a longitudinal flange or wing-like structure extending the whole length and 
1 It is proposed to treat of these cases in detail in a later account. 
[Annals of Botany, Vol. XXXVII. No. CXLVII. July, 1923.] 
