166 MASSACHUSETTS HORTICULTURAL SOCIETY. 



Thrinax argentea and T. imrvijlora are two beautiful plants 

 with fan-shaped leaves. 



Lamia integrifoUa is also an ornamental plant with pinnate 

 leaves. 



To this class of greenhouse plants belong, in brief, all plants 

 that are not hardy, and therefore require to be grown under glass, 

 such as the majoritv of succulent and insectivorous plants, with 

 several bulbs, ferns, and orchids already described. Here also we 

 ma}' include a supplementary class — that of 



Hardy Plants for Forcing. — This word "forcing" means 

 the process of planting, in a pot or pan, an}* of the earlier flower- 

 ing plants, and then keeping them for a month or so in the green- 

 house, by which means one may secure blooms in advance of the 

 natural flowering season. For this purpose onl}- good and strong 

 plants should be selected ; these should be potted in the autumn, 

 and kept in a cold frame till after the first of January, when the}' 

 may be brought into the greenhouse, according to the times when 

 they are desired to be in bloom. They generally take from two 

 to six weeks to come into flower ; any of the early flowering kinds 

 may be forced without much trouble. I will give here only the 

 names of those best adapted for this purpose, as I have already 

 given descriptions of them under Hardy Herbaceous Plants. They 

 are 



Aquilegia Canadensis Sanguinaria Canadensis 



" caerulea Cypripedium acaule 



Phlox amoena " spectabile 



" subulata " pubescens 



Trillium grandiflorum " parviflorum 



" sessile Papaver nudicaule 



" erectum Aquilegia chrysantha 



Viola cucuUata Stylophorum diphyllum 



" " alba Saxifraga peltata 



" pedata " Virginiana 



Polemonium reptans " oppositifolia 



" coeruleum Arisaema triphyllum 



Iris cristata Caltha palustris 



" cuprea Erythronium Americanum 



" verna " grandiflorum 



" versicolor " albidum 



Arabis alpina Thalictrum anemonoides 



