CRUCIFEILE 135 



least of the Isatidese, in Cakile amongst the Cakilineas, and in 

 Chorispora amongst the Baphanese. 



Other genera agreeing with Cheiranthus in the flattened and 

 winged characters of the seeds are Matthiola, Diptychocarpus. 

 Cithareloma, Arabis, Farsetia, Vesicaria, Lunaria, and others. 

 Seeds in several other genera have a broad or narrow margin 

 as in Streptanthus and Lonchophora, but can hardly be called 

 winged, while some of the species of Parrya have broadly 

 winged and others entirely wingless seeds. 



Cheiranthus pygmseus has accumbent or incumbent, straight 

 or convolute cotyledons even in the same pod. 



Wingless seeds whose embryos have accumbent cotyledons 

 are represented by Nasturtium, Cardamine, Aubrietia, Bar- 

 barea, Alyssum, Draba, Cochlearia, Biscutella, Thlaspi, Iberis, 

 Cakile, and Chorispora. The seeds of the genera just men- 

 tioned further differ amongst themselves in being ovoid or 

 turgid as in Nasturtium and Cochlearia, somewhat compressed 

 in Barbarea, and very much so, or almost flat, in Draba, 

 Alyssum, Biscutella, and Iberis. 



Besides Cheiranthus pygmseus above mentioned, there are 

 several other cases where the embryo is slightly but only 

 occasionally modified so that the normally accumbent cotyle- 

 dons become obliquely so or slightly incumbent in species of 

 Barbarea, Draba brunise folia, D. boreale, D. frigida, Cochlearia 

 arctica, C. glauciphylla, Cakile maritima, and possibly some 

 others where the character may be even more marked. 

 Lepidium virginicum also belongs to the group with accumbent 

 cotyledons. It differs markedly from the rest of its congeners, 

 all of w r hich have incumbent cotyledons. Decaptera, consisting 

 of a single species from Chili, has also accumbent cotyledons, 

 although it belongs to the Lepidinea3 like the last. 



Incumbent cotyledons are characteristic of Sisymbriese, 

 Camelinese, and Lepidinese, three tribes of considerable size, 

 while many instances also occur in the Isatidese. The cotyle- 

 dons are likewise incumbent in the Brassicese primarily as well 

 as in genera of the Isatideaa, Cakilinese, and Baphaneae, with 

 longitudinally plicate or conduplicate cotyledons ; but it is 

 convenient to group these types by themselves on account of 

 the distinctly more complicated character of the embryo. The 



