CRUCIFEROUS TRIBE 



7 



17. Nasturtium (Cress) 



1. N. officinale (Common Water-cress). Leaves pinnate ; leaflets 

 roundish or oblong, toothed ; flowers white. Abundant in rivulets 

 and ponds, and extensively cultivated as a salad. The only plant 

 for which it can be mistaken by water-cress gatherers is the Procum- 

 bent apium, which may be distinguished by its hollow leaf-stalks 

 and serrated leaflets, which water-cress has not. Fl. June to 

 August. Perennial. 



2. N. sylvestre (Creeping Yellow Cress). Leaves pinnate ; root 

 creeping ; stems ascending ; flowers small, yellow ; petals longer 

 than sepals. Watery places, not common. Fl. June to Sep- 

 tember. Perennial. 



3. N. palustre (Marsh Yellow Cress). Not so large as the last, 

 and petals smaller. Found in similar places, but more frequent. 

 Fl. June to November. 



4. N. amphibium. Larger than any of the foregoing. Flowers 

 yellow ; petals longer than the sepals. Banks of streams and wet 

 places, not common. Fl. June to August. Perennial. 



18. Sisymbrium (Hedge Mustard) 



1. S. officinale (Common Hedge Mustard). 

 Pods downy, close pressed to the stem ; leaves 

 hairy, deeply lobed, with the points turned 

 backward, the terminal lobe large ; stem rough, 

 with erect branches, 1-2 feet high ; flowers 

 small, yellow. Common in waste places and by 

 roadsides, where it seems to have a peculiar 

 aptitude for collecting and retaining dust. 

 Fl. June, July. Annual. 



2. 5. Irio (London Rocket). Leaves pinnately offSnIle 

 lobed, with the points turned backward, toothed, (Common Hedge 

 smooth ; stem also smooth, erect, branched, about Mustard) 



2 feet high ; flowers small, yellow. A local plant, 

 growing in waste ground, chiefly about London, where, in the 

 spring following the Great Fire of 1666, it sprang up very plenti- 

 fully among the ruins, whence its English name. 



3. S. Sophia (Flixweed). Leaves twice pinnatifid, downy ; 

 petals shorter than the calyx. More slender than either of the pre- 

 ceding, with an erect branched stem about 1 foot high ; and small 

 greenish yellow petals, which are almost hidden by the calyx ; and 

 numerous erect pods, which when ripe have the appearance of being 

 bearded, from the numerous projecting seeds. Waste places and 

 roadsides, not uncommon. Fl. summer. Annual. It was called 

 by the old herbalists Sophia chirurgorum, " the Wisdom of Sur- 

 geons," from its supposed virtue in curing wounds. 



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