CRUCIFERAE 75 



3. Arabideae. Upper and lower nectaries either connected by a lateral ridge, 

 or quite distinct. The lower are always open posteriorly, and closed anteriorly, 

 where they are usually thickened and modified in various ways. The upper are 

 either simple or compound, and are of various forms. (Cardamine, Dentaria, Arabis, 

 Stenophragma, Turritis.) 



4. Sisymbrieae. The lower nectaries embrace the bases of the short stamens 

 in the form of a uniform unbroken pentagonal ring ; the upper are represented by a 

 straight transverse ridge, which is connected by a lateral ridge with the lower 

 nectaries. All six stamens are therefore enclosed by a continuous uniformly thickened 

 ridge. (Sisymbrium, Chamaeplium.) 



II. Siliculosae. 



(a) Latiseptae. 



Only the lower nectaries are developed, and these are always free, i. e. 

 unconnected internally and externally. They are distinctly or approximately 

 three-sided. 



1. Alysseae. The lower nectaries open anteriorly and posteriorly, and are 

 without lateral processes. (Schievereckia, Alyssum, Vesicaria, Cochlearia, Draba.) 



2. Lunarieae. The lower nectaries are without lateral processes, and either 

 united together into a ring or open posteriorly. (Aubrietia, Lunaria.) 



{b) Angustiseptae. 



The upper nectaries are sometimes developed, and resemble the lower ones, 

 with which they are connected by a lateral transverse ridge. 



(a) Only the lower nectaries are developed. They are three-sided, always open 

 posteriorly, open or closed anteriorly, and usually prolonged into ridges laterally. 

 (Thlaspi, Carpoceras, Capsella, Teesdalea, Aethionema, Eunomia.) 



{ff) Only the lower nectaries are developed. They are prismatic, truncated 

 above, free anteriorly and posteriorly, and not prolonged laterally. (Iberis.) 



(y) Either both lower and upper nectaries developed, or only the former, which 

 then occupy the position of the latter, as e. g. in some species of Lepidium and 

 in Coronopus didymus. The lower nectaries are prolonged laterally into a strong 

 ridge, free posteriorly, closed or free anteriorly at their downwardly produced ends. 

 The upper nectaries are simple, and not connected with the lower ones. (Cardaria, 

 Physolepidium, Lepidium, Coronopus.) 



III. Nucamentaceae. 



The relations of the nectaries are not so constant as in the preceding groups, 

 and the various sections of Biscutella converge towards all of them. Either the 

 lower nectaries only are present, or both lower and upper. The lower ones are 

 either prismatic, in which case the upper are columnar with a terminal pit, or — when 

 they only are developed — are represented by a uniformly thickened annular ridge, 

 open anteriorly or posteriorly, or even at both ends. These lower nectaries are 

 produced laterally into long processes, which are connected with the upper nectaries 



