Hydrocharis 



( 433 ) 



Hymenophyllum 



Principal Species : 



canadensis, 1', My., Je., hdy., grn., wli. Orange 

 Hoot. 



HYDROCHARIS. (THE FROG BIT.) 

 The only species in this genus (ord. Hydro- 

 oharidess), Morsus-rana3, is a curious aquatic that 

 is fairly comiuoti in shallow, muddy waters in 

 Britain. It has no horticultural value. 



HYDROLEA. 



Greenhouse herbs and sub-shrubs, all American 

 (ord. Hydrophyllacea;). The flowers are all of 

 some shade of blue, and in shape like those of 

 Campanula isophylla. Propagation, by division 

 and cuttings. A damp, almost boggy situation and 

 rather peaty soil are necessary. 



Principal Species : 

 caroliiiiaiia, 1' to 2', sum., quadrivalvis (net caroliu- 



hdy.(sy. quadrivulvis). iana). 



corymbosa, 1' to 2', sum., spinosa, 1', Je., Jy., hcly., 



hdy., sepals hairy. pale bl. 



HYDROPHYLLUM. 



A small genus (ord. Hydrophyllacea;) of hardy 

 perennial herbs of little horticultural value. 



HYGROMETER. 



laterally a water measurer; fM instrument for 

 ascertaining the amount of moisture in the air. A 

 dry and wet bulb thermometer is the instrument 

 that is generally in use. The "wet" bulb is 

 covered with a piece of muslin connected with a 

 tV\v Brands of woollen material, of which one end 

 is hanging in a small vessel of water attached to 

 the thermometer stand. This vessel is placed a 

 few inches away from the mercury tubes, so that 

 evaporation may not influence the expansion. The 

 degree of humidity is learned by comparing the 

 readings of the dry and the wet bulbs with special 

 hygrometrical tables compiled for use with dry and 

 wet bulb thermometers. For practical purposes 

 the hygrometer is not much employed by gardeners. 

 Almost tlie only instance of its daily use is in the 

 case of Filmy Ferns, which need to have the 

 atmosphere almost at saturation point. Even then 

 a practical man can tell at a glance by the appear- 

 ance of the stones and the walls of the cases 

 whether the conditions are moist enough, without 

 reference to the hygrometer. 



HYMEN^EA. (LOCUST TREE.) 



Ornamental stove evergreen trees (ord. Legu- 

 iniiuisic) with comparatively large, white flowers. 

 Cuttings of ripened shoots will root, in sand in 

 spring if given plenty of bottom heat. The plants 

 are rarely cultivated. 



Principal Species : 



O'ourbaril, 40' to (id', vol., furnishes resin. 



HYMENANDRA. 



A genus of one species (ord. Myrsinepe) of stove 

 evergreen shrubs with handsome foliage. Propa- 

 gation, by cuttings of the young shoots, taken off 

 with a heel of the old wood in spring, and rooted 

 in heat. Soil, loam two parts, leaf mould one part, 

 and sand. 



Only Species : 



Wallichii. 2' to 4', st., pic. 



HYMENANTHERA. 



Greenhouse and half-hardy shrubs (ord. Violarije) 

 of stiff habit, with small flowers. They are rarely 

 cultivated. Crassifolia is a neat hardy shrub. 



HYMENOCALLIS. 



Description. .Stove and greenhouse bulbous 

 plants (ord. Amaryllidea;), -with thick leaves and 

 usually white, fragrant flowers. They are allied 

 closely to Pancratiums ; indeed, some of the species 

 commonly cultivated as Hymenocallises are in 

 reality Pancratiums, and vice versa. 



There may be said to be three sections in the 

 genus, one needing stove treatment, the second 

 flourishing in the greenhouse, and the third being 

 almost hardy. The last, to which the name of 

 Ismene is sometimes given, will, however, only do 

 in sheltered positions in the southern counties. 

 They may be lifted, and the bulbs stored in sand 

 for the winter. 



Propagation. By offsets, which are produced 

 from the larger and older bulbs. These should be 

 carefully separated at potting time, and grown on 

 in sandy soil in a close frame. 



Soil. Good loam two parts, rotten cow manure 

 one part, and leaf mould one part, with sand. 

 Pot rather loosely. 



Other Cultural Points. The bulbs do not need 

 potting often ; once in two years is enough, but an 

 annual top-dressing of new soil is helpful. The 

 stove and greenhouse bulbs must always be kept 

 moist, even in winter. Mealy bug is the worst 

 pest. Kemedy, the sponge. 



Principal Species : 



c.-ilnthina, Mch., Ap., 

 grh., greenish wh., very 

 Mvret (xi/ii. Pancratium 

 calathinum). 



macroatephaua, 2', Feb., 

 St., wh., sweet. 



ovata, 1' to 2', Oct., St., 

 wh., fragrant (//*. 

 atnoeua and Paucra- 

 Other Species : 



Amancaes, 2', grli., yel. 

 (*;/. Pancratium Aman- 

 caes of Botanical Mttya- 

 zine 1224). 



audreaiia, 1J', wh. (XI/H. 

 Ismene audreana). 



deflexa, St., said to be a 

 natural hybrid (xi/us. 

 Choretis and Ismene 

 deflexa). 



expansa, 2', Nov., st., 

 gru., wh. (xifn. Pancra- 

 tium cxpansum of Bot- 



tiuni anicenum of Sot- 

 anical Maijuzine 1467, 

 P. fragrans, and P. 

 ovatuin). 



speciosa, 1' to K', st., 

 wh., sweet (/. Paii- 

 cratium speciosum of 

 Jiotiiiiieal Magazine 

 1453). 



lacera, 1.}', My., grh., wh. 

 (/.. rotate and Pan- 

 cratium rotatum of Sot- 

 nnical Mai/azine 827). 



macleana, 2', Je., nearly 

 hdy., grh., wh. , grn. 

 (XI/H.I. virescens and 

 Ismene macleana of 

 Butaniml Muynzixr 

 3675). 



tuhiflora, st. (tyn. Pan- 

 cratium guianeiise). 



undulata, 1', Ap., st., wh. 

 (.'/. borskiaua;. 



antt'al M<t<in:j!ii' 1941). 

 harrisiaua, 1 ', Je. ,grh. ,wh. 



HYMENODICTYON. 



Stove trees (ord. Kubiaceze) with small Cowers, 

 of no garden value. 



HYMENOPHYLLUM. (FILM* FEBNS.) 



Description. Stove, greenhouse, and hardy 

 Ferns (ord. Filices), the delicate, Eemi-tiMMMUrent 



appearance of whose fronds ha- led to their being 

 described as Filmy Ferns. There are upwards 

 of eighty species, chiefly requiring stove and 

 greenhouse treatment. Two are Punish, viz. 

 unilateral); and tiinliridgenso. but ewn t! ...... 



Jli/drnmu.itiis (see Aphclandm). 

 ilydropi-ltis (see lirasenia). 



Ili/Hii-inii/iiiiii (si':- Arrii^t if/i u HI ). 

 (gee Acrostich inn ). 



