(6) 



2. Lemna. Perigonium compressed, grow- 



ing out of the margin of a thallus. 

 Aquatic. 



3. Scirpus. Glumaceous. Spikelets imbri- 

 cate from all sides. Inferior glumae 

 (1-2) sterile, but not smaller than the 

 rest. Perigonial bristles not exserted. 

 Fruit, a nutlet, apiculate by the persist- 

 ent base of the style. Aquatic. 



4. Fraxinus. Ovary 2-celled, laterally 

 compressed. Fruit, a samara, Tree. 



5. Acaena. Perigonium lobes valvate. Fruit 

 an akene enclosed in the perigonium. 

 Style terminal. 



6. Alchemilla. Perigonium urceolate, brac- 



teolate, not spinose. Akene enclosed in 

 the perigonium. Style lateral. 



B. Floral parts complete, inferior, regular. 



1. Fraxinus. Fruit, a samara. Tree. 



2. Lepidium. Fruit, a silicula, laterally 

 compressed. 



C. Floral parts complete, inferior, irregular. 



a. Ovary entire. 



1. Veronica. Calyx herbaceous 4-parted. 

 Ovary 2-celled. Fruit, an emargmate 

 capsule. Leaves opposite. 



