GREENHOUSE AND CONSERVATORY PLANTS 139 



dium composed of sphagnum, sand and charcoal. I much prefer the 

 first method. 



NERIUM (Oleander). Much grown as a tub plant, for which 

 it is well suited. Old plants should be kept as dormant as possible 

 during the Winter. 



Propagation. Cuttings are rooted early in the season, and 

 plunged outside when established in pots. 



NERTERA (Bead Plant). The only species of importance is 

 N. depressa. If we desire to have something of real beauty in the 

 cool greenhouse a few small tufts of this close-growing dwarf plant 

 will satisfy most people. It never grows over 2 inches in height, 

 but it is usually covered with myriads of orange-red berries. 



Culture. When not in bloom or in fruit it will be best to place 

 the plants under the bench of the greenhouse where, especially if 

 the pots are plunged, they will keep in a healthy condition. It re- 

 quires a sandy soil with a little leafmold. 



Propagation. It may be propagated either by seed or division. 



OCHNA. 0. multiflora is an interesting and beautiful cool 

 greenhouse shrub. The flowers are yellow. The calyx, at first 

 green, changes to a brilliant red on the ripening of the fruit. 



Culture. It requires a soil of fibrous loam with good drainage. 



Propagation. Propagated by cuttings taken in the Fall. 



ODONTOGLOSSUM. With the exception of 0. citrosmum 

 the species of this noble genus have a struggle for existence in the 

 District of Columbia. Farther north they succeed better. 0. cris- 

 pum is one of the most popular, of which there are many beautiful 

 varieties. 



Culture. The Odontoglossums are cool house Orchids, 65 de- 

 grees, and the main difficulty of their culture results from injury 

 due to high Summer temperature. They require abundant ventila- 

 tion, good light, but some shade. 



ODONTONEMA (Thyrsacanthus). 0. Schomburgkianum is 

 a shrubby plant attaining a height of 6 feet. There is nothing just 

 quite like it with its graceful long sprays of red flowers all during the 

 season. These plants are very seldom seen in gardens of amateurs 

 because, like many other things, they cannot be sold to plant-lovers 

 in public markets unless they are in flower. 



