844 
D l O 
but in fummer, when they are growing vigoroufly, they 
fhould be watered three or four times a-week ; and in 
warm weather the glades fhould be opened to admit a 
large fliare of free air. When feeds are received, they 
fhould be immediately fown in pots, and plunged into a 
hot-bed; where, if it be early in the fpring, the plants 
will come up the fame feafon ; but, when they are fown 
late, the feeds often remain in theground till the follow¬ 
ing fpring before they vegetate : in this cafe the pots 
mu ft be fcreened from froft during the winter, and put 
into a new hot-bed in the fpring. They may alfo 
be increafed by cutting the roots in pieces, as pradfifed 
for potatoes ; putting each piece in a pot filled with frefli 
earth, and plunged into the bark-pit; giving them little 
water until they flioot, left they fhould rot. The roots 
do not grow to any great fize here ; and the plants hav¬ 
ing little beauty, feldom flowering, and requiring much 
care and room, they are feldom allowed a place in our 
ftoves, except in very curious collections. 
DIOSCO'RTDES (Pedacius), an eminent phyfician 
and botanift of antiquity, native of Anazarba in Cilicia. 
He is fuppofed to have lived in the reign of Nero, but 
fome of the learned have placed him under Adrian, and 
made him pofterior to Pliny. He followed arms in five 
earlier part of life, but afterwards attached himfelf to 
the ftudy of medicinal fimples, and travelled for that 
purpofe in Europe and Afia. He compofed in Greek a 
work on the materia medica, which for many ages was 
of the higheft authority, and has been copied by the an¬ 
cient Greek phyficians, the Arabians, and the moderns, 
down to the revival of fcience. It has, however, all the 
rudenefs and inexactitude of antiquity, and could only 
have been valuable as a guide to more accurate works. 
Befides fimples, he treats of preparations and compound 
remedies ; and feveral of his prefcriptions have come 
down to modern pradfice. His whole works, Greek and 
Latin, were edited by Saracenus, at Lyons, in 1598, folio; 
which edition is preferred to all others. There are other 
editions of the whole, or parts, and numerous tranfla- 
tions and commentaries. The verlion of Ruellius is ac¬ 
counted the beft. 
DIOSCU'RI, or fons of Jupiter, a name given to Caf- 
tor and Pollux. There were feftivals in their honour, 
called diofcuri, celebrated by the people of Corcyra, and 
chiefly by the Lacedaemonians. They were obferved 
with much jovial feftivity. The people made a free ufe 
of the gifts of Bacchus, and diverted themfelves with 
fports, of which wreftling matches always made a part. 
DIOS'MA, J'. [Aio? 0 a-[xn, Jovis feu divinus odor ; fo 
called from its pieafant fmell.] African Spiraea; in 
botany, a genus of the clafs pentandria, order monogynia, 
natural order of aggregatae, (rutacese, JufT.) The gene¬ 
ric charadters are—.Calyx: perianthium five-leaved ; leaf¬ 
lets ovate, acute, permanent. Corolla: petals five, ovate, 
obtufe, feflile, eredi, fpreading; nectaries five, placed on 
the germ. Stamina: filaments five, fubulate ; antherae 
fubovate, erect. Piftillum : germ crowned with the nec¬ 
tary ; ftyle fimple, length of tiie ftametis; ftigma obfeure. 
Pericarpium: capfules five, ovate-acuminate, comprefled, 
conjoined inwardly at the margin, diftant at the tips, gap¬ 
ing at the upper future. Seeds: folitary, oblong, ovate- 
depreifed, acuminate at the point: an elaftic aril, gaping 
on one fide, involving each feed. — EJfential C/iaratter. 
Corolla five-petal led; nectaries five on the germ; cap¬ 
fules three or five conjoined ; feeds veiled. 
'This is a multiform genus, as to (ex, figure of nedfa- 
ries, number of capfules; hence it was divided into liar- 
togia and diofma ; but further obfervations have brought 
them back into one genus. Syft. Veget. p. 199. There 
are fpecies with monoecous flowers, others with herma- 
phrodite ; others with ten ftamens, of which five are 
fterile ; and others differ otherwife from their congeners. 
The fpecies are all fhrubs, bearing the refemblance of 
heaths. The leaves are either oppolite or fcattered, fre¬ 
quently crowded and linear, fometimes having the edge 
2 
D I O 
underneath dotted. The flowers are in corymbs, or heads 
at the ends of the branches. The calyxes of fome are 
glandulotis and dotted. They are natives of the Cape of 
Good Hope. 
Specks, r. Diofma oppofitifolia,oroppofite-leaved diof¬ 
ma: leaves fubulate,acute,oppofite.Thisrifes to the height 
of three feet; the branches are very long and flender, 
and are produced from the ftem very irregularly. The 
leaves are placed croffwife in pairs, and are pointed ; 
every evening they clofe up to the branches. The flow¬ 
ers are produced along the branches from between the 
leaves; and in the evening, when they are expanded, 
and the leaves clofely embrace the branches, the whole 
plant appears as if covered with fpikes of white flowers ; 
and, as it continues a long time in flower, it makes a fine 
appearance when intermixed with other exotics in the 
open air. It was introduced in 1774, by Mr. Francis 
Maffon, into the Kew garden ; but had been cultivated 
before by Miller. 
2. Diofma hirfuta, or hairy-leaved diofma : leaves li¬ 
near, hirfute. This fort makes a very handfome flirub, 
growing to the height of five or fix feet. Stalks woody, 
fending out many flender branches. The leaves come 
out alternately on every fide. Flowers in fmall clufters 
at the ends of the (hoots ; they are white, and are fuc- 
ceeded by ftarry feed-veffels, having five corners, like 
thofe of the ftarry anife ; each of thefe corners is a cell, 
containing Qne fmooth, fhining, oblong, black, feed : 
thefe feed-veffels abound with a refin, which affords a 
grateful (cent, as does alfo the whole plant. 
3. Diofma rubra, or red-flowered diofma : leaves li¬ 
near, mucronate, fmooth, keeled, dotted in two rows be¬ 
neath. This is of humbler growth, feldom above three 
feet high, and fpreads out into many branches; leaves 
refenibling thofe of heath; flowers in clufters at the 
ends of the branches, like thofe of the fecond fort, but 
fmaller, and the bunches not fo large. According to 
Linnaeus, it has the habit and leaves of juniper; thefe 
are fmooth, and fubtriquetous. 
4. Diofma ericoides, or fweet-feented diofma: leaves 
linear-lanceolate, convex beneath, imbricate in two rows. 
This is a low bulky ftmib, which feldom rifes above two 
feet high, but fpreads out its branches far on every fide. 
The leaves are narrow and fmooth, of a light green co¬ 
lour, and being ranged on each fide the branches, appear 
flat on the upper and under fide; when they are bruifed, 
they emit a very ftrong penetrating odour. The flowers 
are produced (ingly from between the leaves; they are 
white and tinged on their upper furface. The nettary 
is lefs vifible, and the feed-veffels are much fmaller. 
The Hottentots ufe this and other fpecies to (cent their 
ointments. 
5. Diofma Capenfis, or Cape diofma : leaves linear, 
three-lided, dotted beneath. 6. Diofma capitata, or 
headed diofma: leaves linear, imbricate, fcabrous, cili- 
ate ; flow'ers in fpiky heads. 7. Diofma unicapfularis, 
or one-capfuled diofma: leaves linear-lanceolate; cap¬ 
fules one-celled. 8. Diofma latifolia, or broad-leaved 
diofma: leaves ovate-crenate ; peduncles axillary, foli¬ 
tary ; ftem villofe. 9. Diofma marginata, or marginated 
diofma : leaves cordate-attenuated, membranous-edged. 
10. Diofma barbigera, or bearded diofma: leaves cor¬ 
date, ftem-clafping; petals bearded. 
11. Diofma retragona, or quadrangular diofma : leaves 
cordate, retufe, folded together and keeled, ciliate; 
branches one-flowered. This fpecies is lingular, and dif- 
tinguifhed from the reft by the leaves being fo clofe to¬ 
gether, that the whole ftem is covered with them; by 
the branches being quadrangular and thicker towards the 
top ; and by the large, folitary, terminating, flower. 
12. Diofma cuprellina, or heath-leaved diofma : leaves 
ovate, three-cornered, imbricate ; flowers folitary, ter¬ 
minating, feflile. 13. Diofma imbricata, or imbricated 
diofma : leaves ovate, mucronate, imbricate, ciliate. 
14. Diofma lanceolata, or fpe.ir-fliaped diofma: leaves 
elliptic. 
