SELECT LISTS OF PLANTS. 275 



and for this reason they are objectionable, and rarely planted except 

 for hedges. There are, however, several unarmed varieties of the most 

 hardy and valuable species, and these are well worthy of general culti- 

 vation as ornamental trees. The species are propagated by seed, sown 

 as soon as gathered, and removed from the pods, or mixed with moist 

 sand and buried in the open ground. If the seeds are kept dry over 

 winter they should be scalded or steeped in warm water for a day or 

 two before sowing. It is always advisable to soak old seeds and keep 

 them in a warm place until the sprouts begin to appear, before sowing ; 

 for, if they do not germinate while in a warm place in the house, 

 they will not grow when sown in the field. The varieties may be propa- 

 gated by grafting on seedling stocks in the open air. (See Chapter 

 XVIII., Selecting Stocks.) 



Gymnocladus (Kentucky Coffee Tree). Only one species, the G. 

 Canadensis, common in the Middle and Western States, thriving best in 

 rich, moist soils. A large, deciduous, ornamental and timber tree, with 

 very long, bi-pinnate leaves. Seeds produced in long, broad pods large 

 and very hard when mature, requiring the same or similar treatment as 

 those of the Honey-locust. English nurserymen are said to propagate 

 the Kentucky Coffee Tree by cuttings of the roots, but there is no occa- 

 sion to resort to this mode here, as seeds are to be obtained in abundance. 



Halesia (Snowdrop, or Silver-Bell Tree). A small genus of very 

 ornamental, deciduous shrabs, of the Styrax Family. Only three species, 

 all indigenous to the Southern States ; one extending as far north as 

 Virginia, but all hardy in much colder latitudes, as I have never known 

 them to be injured in my grounds in Northern New Jersey. Propagated 

 by seeds, layers, and cuttings of the roots. Seeds, a hard, bony nut, 

 enclosed in a persistent, fibrous husk. The seeds do not usually germi- 

 nate until the second year, and should be sown where they can be kept 

 moist during the first summer. By covering the seed bed with mulch, 

 this condition can be secured with but little trouble or expense. Seeds 

 self sown, under Pine trees, in my grounds, germinate readily without 

 any artificial aid. (See Chapter XVIII., on Selecting Stocks, Styrax, etc.) 



Halimodendron. A handsome little deciduous shrub from Sibe- 

 ria, closely allied to the Caragana, which see for propagation ; also Chap- 

 ter XVIII., Stock for Halimodendron. 



Hamamelis (Witch-Hazel). Tall, hardy shrubs, of no especial value 

 or beauty, having the rather singular habit of blooming late in fall or 

 early winter, and ripening the seeds the following autumn. Flowers 

 small, bright yellow, in clusters in the axils of the leaves. A species 

 has recently been introduced from Japan (H. Japomcd), also one variety. 

 Propagated by seeds and layers. The Japan species may be grafted on 

 the American, but it is rather difficult to make the cions unite in the 

 open air. 



Heltanthemum (Rock Rose). An immense genus of shrubby and 

 herbaceous plants. The shrubby species often cultivated in conserva- 



