DICOTYLEDONES— MONOCHLAMYDE.E 



258 



with little or no albumen; embryo straight; cotyledons folia- 

 ceoiis ; radicU superior. 



Division of the Order and Illustrative Genera. — This 



order may be divided into two sub-orders or tribes as follows : — ■ 



Sub-order 1. Celtece. — Ovary 1-eelled, with drupaceous fruit. 



Illustrative Geriera : — Celtis, Tourn. ; Mertensia, H. B. K. 



Fig. 1011. 



Sub-order 2. U hue ce.^O vary 2-celled, 



with usually samaroid fruit. 11- 



lustrative Genera : — Planera, 

 Gmel. ; Ulmus, Linn. 



Distribution and Numbers. — They 

 are chiefly natives of the northern 

 regions of the world. There are about 

 60 species. 



Properties and Uses. — Some are 

 valuable timber trees. The bark and 

 fruit of others are bitter, tonic, and 

 astringent ; and a few possess aromatic 

 properties. 



Order 37. Platanace^, the Plane 

 Order. — C h a r a c t e r . — T rees with a 

 watery juice. Leaves alternate, pal- 

 mately lobed, with deciduous sheathing 

 stipules. Floivers unisexual, monoe- 

 cious in globular amentaceous heads ; 

 achlamydeous. Male flowers with 1 

 stamen and a two-celled linear anther. 

 Female floivers consisting of a 1-celled 

 ovary and a thick style ; ovules 1 — 2, 

 pendulous. Fruits arranged in a com- 

 pact rounded head, consisting of clavate 

 achsenia with persistent stj^les. Seeds 

 1 or rarely 2, pendulous ; embryo 

 straight, in very thin albumen, with an 

 inferior radicle. 



Distribution and Numhers. — They 

 are natives principally of North Ame- 

 rica and the Levant. Platanus, Linn., is the only genus, of 

 which there are 5 or 6 species. 



ProiJerties and Uses. — Of no particular importance, except 

 that, from their bemg large handsome trees, and flourishing well 

 in large towns, they are commonly planted in our parks and 

 squares. The leaves closely resemble in appearance those of 



Fig. 1011. Branch of the Plane 

 tree (Pla/anux orientalist, 

 with amentaceous lieads 

 of aclilamydeous female 

 flowers. 



