1900 SUPPLEMENT—RECENT INTRODUCTIONS, 
&C. Ble 
Dendrophylax—continued. 
eenish-white, lanceolate, acute ; lip white, with a slender spur 
in. long. Roots long, green. 1888. Closely allied to D. funalis. 
D. funalis (rope-like). #. greenish-white, 4in. long; lip. 4in. 
broad, about half as long as the subulate-tiliform, straight- 
descending spur; scapes distantly sheathed, few-flowered, lin. 
to 4in. long. Roots often several feet long. 1846. Syn. 
Angrecum funale (B. M. 4295). 
DENDROSERIS. Syn. Rea. Flower-heads usually 
white, mediocre or large, produced at the tips of the 
branches of an ample panicle. Leaves alternate, petiolate 
or the upper ones sessile, often large, entire, lobed, or once 
or twice pinnate, glabrous. 
DENDROSPARTUM. Included under Genista 
(which see). 
DENITRIFICATION. This is a soil condition 
resulting from the removal of nitrogen. Whenever the 
soil is ina condition unfavourable to nitrification, there is 
danger that not only may nitrates not be formed, but that 
there will be a loss of nitrogen from those nitrates which 
are present. This loss is due to a process known as 
Denitrification—a process which is also dependent on micro- 
organisms. The Denitrification organisms flourish under one 
condition, which is directly opposed to the corresponding 
condition favouring nitrification—namely, the absence of 
oxygen. Under that condition the nitrates may be reduced 
or changed back to nitrites, and the nitrites are often ~ 
further reduced till they lose their nitrogen altogether by 
having it pass off into the air as gaseous nitrogen. 
Denitrification may take place, therefore, in waterlogged 
soils, in badly-drained pot-cultures, and in the inner 
parts of manure or compost heaps, when air is measurably 
excluded. organic manure, therefore, which is 
effective for plant growth when applied in small 
quantity, may thus become injurious when made 
use of in excess. The supply of atmospheric oxygen toa 
soil is effectually prevented if the soil is kept in a satn- 
rated condition with stagnant water. This condition alone 
is sufficient to set up an energetic Denitrification, by which 
process the growing plants must considerably suffer. 
Professor Bréal furnishes a further excellent example of 
the active Denitrification which takes places in a soil kept 
saturated with water. He placed some garden soil in a 
percolator, and consolidated it by pressure; the column 
was about l5in. high. Water more than sufficient for 
saturation was then poured upon the soil; when the water 
had run throngh it was poured back again over the soil, 
and this treatment was continued for some time. The soil 
at the commencement of the experiment was in an active 
state of nitrification, and the drainage-water was at first 
rich in nitrates; but at the end of three weeks the 
nitrates had entirely disappeared from the drainage-water, 
though no water had been removed from the soil. 
on Included under Dicksonia (which 
see). 
DENTARIA. Bentham and Hooker include this genus 
under Cardamine (which see). One or two hybrids have 
been raised by crossing D. digitata, D. pinnata, and 
D. polyphylla. The following may be described : 
D. Killisii (Killis’s).” A handsome hybrid between D. digitata 
and D. polyphylla ; itis more robust than either of the parents. 
Alps, 1889. 
D. pinnato-digitata (hybrid). 1. like those of D. digitata. 
@. pinnate. Jura Mountains, 1889. An interesting hybrid, inter- 
mediate in character between the two parents indicated in the 
name. 
DENTIDIA. A synonym of Perilla (which see). 
DEPARIA. The soil most suitable to Deparias, which 
are not very strong growers, is a compost of an open nature, 
formed of about equal parts fibrous peat, leaf-mould, and 
silver-sand. Special attention should be given to the 
drainage : deficiency in this respect is the principal cause of 
failure in the cultivation of these plants, which at all times 
require a.liberal supply of water at the roots, but dislike 
syringing overhead. The Deparias should also be carefully 
protected against the direct rays of the sun. They are 
usually propagated by division of the crowns in March and 
April, their spores being seldom known to germinate. 
D. Moorei. This species, which is probably the prettiest of the 
enus, was formerly known as Cionidium Moorei and Trichocarpa 
ooret. A barren frond is well shown in Fig. 340. 
DEPRESSED. Oblate ; somewhat flattened vertically 
or endwise. 
DERMATOBOTRYS (from derma, dermatos, skin 
or bark, and botrys, a cluster; in allusion to the position 
and disposition of the flowers.). OrRp. Scrophularinex. 
A monotypic genus. The species is a small, epiphytic, 
deciduous shrub, with a long, naked stem as thick as the 
wrist, and brown, sub-quadrangular branches. It requires 
greenhouse treatment. 
D. Saundersii (Saunders’s). 1. 2in. long, drooping in whorls 
below the new leaves ; calyx small, five-parted ; corolla pale red, 
tubular, gradually dilated from a slender base, the five short, 
spreading lobes yellow within; anthers five. Winter. JZ. 2in. to 
6in. long, rather fleshy, ovate or oblong, sub-acute, coarsely 
toothed. Natal and Zululand, 1892. (B. M. 7369.) 
DERMATOPHORA NECATRIX. 
Fungi. 
DESCENDING. Directed downward. 
DESCHAMPSIA (named in hononr of M. Deschamps, 
of Saint Omer, one of the naturalists selected for the 
expedition in search of the unfortunate Lapeyrouse). 
Syn. Campelia (of Link). Orb. Graminee, A genus 
including about a score species of mostly hardy, perennial 
Grasses, broadly distributed over temperate and frigid 
regions, and on mountains within the tropics. Spikelets 
paniculate, often larger than in Aira; glumes two, the 
lower one empty; panicle terminal, sometimes narrow and 
dense, often lax. Leaves narrow, convolute-terete or flat. 
Two species call for mention here. They thrive in any 
ordinary soil, in moist, shady places, and may be 
propagated by seeds. 
D. czespitosa (tufted). 1. silvery-grey or purplish ; peor very 
elegant, usually viviparous, 6in, to 12in. long, with spreading, 
slender, almost capillary branches. Summer. J. rather stiff, 
flat, very rough on the upper surface, Britain. A handsome, 
tall Grass, forming large, dense tufts. 
D. flexuosa (waved). The correct name of Aira flexuosa. 
DESFONTAINEA. Linkia (of Persoon) is synony- 
mous with this genus. 
See Vine 
Fic. 340. BARREN FROND OF DEPARIA MOOREL. 
DESIGNS. ‘Sve Bedding-out, Bedding Plants, 
Garden, and Landscape Gardening. 
DESMIDORCHIS. 
A synonym of Boucerosia 
(which see). 
