40 GERANIUM ORDER 



RUTACEAE RUE FAMILY 



Sepals 4-5, often united, petals 4-5, stamens 4-8, ovary 2-celled, style 1, 

 fruit a 2-lobed capsule, or a winged samara ; flowers solitary or in terminal 

 clusters ; shrubs or trees with simple or palmately compound leaves. 



1. Leaves palmate, consisting of 3 leaflets; fruit 



winged PTELEA 



2. Leaves simple; fruit 2-lobed, not winged THAMNOSMA 



PTELEA Linne 1753. HOPTREE 



(Greek name of the elm) 



PL 4, fig. 5. 



Sepals 4-5, united, petals 4-5, greenish white, stamens 4-5, ovary 2- 

 celled, style 1, fruit round, broadly winged, 1-seeded; flowers in terminal 

 clusters ; leaves of 3 lance-ovate to obovate leaflets ; shrubs or low trees. 

 Shrub 5-20 ft. high; leaflets 1-3 in. long; fruit 12-20 



mm. wide P. trifolidta 



THAMNOSMA Torrey 1858 



(Gr. thamnos, bush, osme, odor) 



PL 4, fig. 6. 



Sepals 4, petals 4, yellow or tinged with purple, stamens 8, ovary 2- 

 celled, style 1, fruit a 2-lobed capsule, with 4-6 seeds in each lobe; flowers 

 solitary ; leaves simple, linear, heavy-scented ; low shrubs. 

 Stems branched at base, 3-12 in. high; leaves 1-2 cm. 

 long T. texana 



LINACEAE FLAX FAMILY 



Sepals 5, petals 5, yellow or blue, falling after a few hours, stamens 5, 

 united below, ovary 4-5-celled, or 8-10-celled by new partitions, styles 5, 

 fruit a capsule opening by 5-10 valves ; flowers in cymes or racemes ; an- 

 nual or perennial herbs with alternate, opposite or whorled simple entire 

 leaves. 



LINUM Linne 1753 FLAX 

 !>.., (Gr. linon, Lat. linum, flax) 



PL 7, fig. 1. 



Characters of the family. 

 1. Flowers blue 



a. Petals 3-4 times, fruit 2-3 times, longer than 



the obtuse sepals L.perenne 



