HENDERSON'S HANDBOOK OF PLANTS. 



367 



HEA 



essential requisite in a heating apparatus, 

 viz., efficiency, economy of fuel and 

 attention, safety, and simplicity, con- 

 sists of a series of steam tubes of not less 

 than two inches diameter, placed under the 

 benches or suspended along the walls, as 

 may be best suited, in such a manner as 

 to drain themselves into a water and 

 steam-tight vessel, which, therefore, has 

 to be situated at the lowest convenient 

 point. These tubes or pipes should pre- 

 sent a radiating surface of about one 

 square foot to ten square feet of glass 

 surface; or, better expressed, one square 

 foot to seventy cubic feet of space to be 

 heated to at least fifty-five degrees in any 

 weather up, or rather down to twenty- 

 five degrees below zero, and at a pressure 

 of steam not to exceed fifteen pounds io the 

 square inch. If a higher temperature is 

 desired, say from sixty-five to seventy 

 degrees, make the radiating surface equal 

 say one square foot to fifty cubic feet for 

 the same pressure of steam. The form 

 of boiler is immaterial; whichever is best 

 suited and most economical for the par- 

 ticular fuel you use, is the one to adopt, 

 and its capacity should not be less than 

 one-horse power to 120 square feet of ra- 

 diating surface, which, represented in 

 two-inch pipe, is, in round numbers, 240 

 lineal feet. This boiler should be provided 

 with an automatic and positive-acting steam 

 trap, to return the condensation which 

 gathers in the vessel above-mentioned to 

 the boiler, thereby maintaining at all times 

 sufficient water; in fact, establishing com- 

 plete circulation, much the same as by 

 hot water; and when you add to this an 

 efficient automatic damper-regulator, (do 

 not let yourself be humbugged into any 

 diaphragm nuisance,) you have 'The 

 coming heating apparatus,' compared to 



HET 



which any other hitherto in use, of what- 

 ever form, is a cumbersome, wasteful, and 

 inefficient affair. Five seasons' use speaks 

 volumes for its superiority, and it has 

 already the entire endorsement of some 

 of the most successful and progressive 

 commercial florists of the country." 



Hederacece. Another name for Araliacece, 

 which see. 



Heliotropiacece. A group of corollifloral Di- 

 cotyledons, considered by most botanical 

 writers as a sub-order of Ehretiacece, 

 which see. 



Helmet. The hooded upper part of some 

 flowers, as in the Monkshood; the same 

 as Galea, which see. 



HemerocallidecB. The Hemerocallis family, 

 a sub-division of the natural order Lilia- 

 cece. HemerocaUis, Funkia, Agapanthus, 

 and Tritonia are examples. See LUiacece. 



Hemi. In Greek compounds means half 

 or halved. 



Hepta. In Greek compounds means 

 seven. 



Heptagynia. Having seven pistils. 



Heptandria. Having seven stamens. 



Herb. A plant that does not possess a 

 woody stem. 



Herbaceous. Merely green, or thin green 

 and cellular, as the tissue of membran- 

 eous leaves. Also producing an annual 

 stem from a perennial root. 



Hermaphrodite. Having both stamens and 

 pistils in one bloom, as in most common 

 plants. 



Heterocarpus. Where a plant bears fruit 

 more or less distinguishable into two 

 separate forms. 



Heterocephalous. Bearing in the same indi- 

 vidual, heads of entirely male flowers, and 

 others entirely female. 



Heterogamous. Bearing flowers of different 



