AN ENCYCLOPADIA 
OF HORTICULTURE. 87 
Peucedanum—continued. 
are British plants: P. officinale (Sulphurwort), P. Ostru- 
tyium (Masterwort), P. palustre (Milk Parsley), and P. 
sativum (Wild Parsnip). For culture of the last-named, 
see Parsnip. 
P. sativum (cultivated). Parsnip. fl. bright yellow, small; 
umbel-rays many, stout, long. July and August. iA shiny, 
pinnate ; leafiets two to five pairs, lin. to in. long, sessile, ovate, 
inciso-serrate. Stem 2ft. to 3ft. high, stout, angled, furrowed, 
fistular. Europe (Britain), Siberia. Annual or biennial. The 
Parsnip has been cultivated since the time of the Romans. Syn. 
Pastinaca sativa. 
PEUMUS (said to be the native name in Chili). 
Syns. Boldea, Ruizia. ORD. Monimiacee. A monotypic 
genus. The species is a small, greenhouse, evergreen, 
fragrant tree. It succeeds in a compost of sandy peat, 
and may be increased by cuttings. 
P. Boldus (Boldus). ji. white, dicecious, disposed in terminal 
cymes, which are shorter, or scarcely longer, than the leaves; 
male perianth larger than the female, of ten or twelve lobes, two 
or three-seriate, imbricated. May. I. opposite, or rarely alternate, 
coriaceous, ovate-elliptic, acute, entire. A. 20ft. Chili, 1844, 
(B. R. 1845, 57, under name of Boldoa fragrans.) The leaves are 
used in medicine for the purpose of assisting digestion, &c. The 
fruit is sweet, and is eaten in Chili, and the k is used for 
tanning. 
PEYROUSIA, of Sweet. A synonym of Lapey- 
rousia (which see). 
PEZIZA. A large genus of Fungi, of which by far the 
greater number live on decaying remains of animals or of 
plants, or on dung or earth in which there is abund- 
ance of decaying organic matter. A few grow upon and 
injure living plants, both wild and cultivated. The 
vegetative system of the Fungus consists of mycelium 
hidden in the substance on which it grows. The con- 
spicuous part, by means of which the species are iden- 
tified by mycologists, is that specialised for reproduction. 
ee, 
Fic. 97. PEZIZA COCCINEA (natural size). 
This is in the form of a cup, rather shallow in some, 
deep in others (see Figs. 97, 98, and 99). This large 
genus has been broken up into sections, treated by some 
mycologists as genera, characterised by consistence, 
Presence or absence of a stalk, of hairs externally, of 
a membrane closing the young cups, &c.; but the as- 
semblage of species, as a whole, is a very natural one. 
ey vary in size of cups from several inches across to 
a size too small to be seen without a lens. The inner 
surface of the cup is lined with a layer of large cells, of 
cylindrical or club-shaped form (asci), standing erect 
(see Fig. 98, d), in each of which lie eight small, oval, 
Smooth, or, less often, warty cells (spores), which are set 
by the asci bursting at the end next the surface. 
Sometimes the spores are emitted in a thin cloud, when 
the Fungus is exposed to dry air. 
While many of the species produce the cups on a 
mycelium of loosely-woven hyphæ, or filaments, formed 
in the substance from which the Fungus is drawing its 
nourishment, other species form a sclerotium, i.e., a mass 
Composed of densely interwoven hyphæ grown together, 
80 as to resemble a true tissue (see Fig. 99, sc). This 
_ body is usually black and hard outside, but pale and soft 
inside. It is fitted to resist changes of temperature 
winter; and in spring it aids in reproduction by 
producing one or more cups, of the structure deséribed 
above. A very common and well-known example is the 
sclerotium, so common in winter on dead herbaceous 
stems, called S. durum. In spring. there is a grey 
mould, formed largely on it (Polyactis cinerea), which 
produces myriads of round conidia or spores. Later on, 
long-stalked cups of a Peziza (P. Fuckeliana) grow out 
from the same sclerotium. oe 
(sc); b, Cup, cut le: F 
layer of Asci; d, . — 
from small-celled Tissue of Cup ( about 
These remarks must be restricted to the species of 
Peziza that give rise to disease in cultivated plants, 
and therefore the other kinds will not be again referred 
to. The most hurtful recorded in Britain is one that 
has ed destructive to Potatoes in Ireland and in 
Sootland ; and it has also been injurious in Norway. 
The plants become covered with a thick felt of 
mycelium all over the diseased parts; and amidst 
this are formed masses of compact tissue (sclerotia), 
at first pale, then becoming dark. Some of these 
masses are as large as a small bean, but few ex- 
ceed a small pea in size. In a short time, the 
host-plant perishes, but the Fungus goes on to 
perfect its sclerotia. From each of these, in the 
summer, there grow two or three cups. When 
fully grown, these are nearly flat, and about 
zin. or zin. across, and they are supported on a 
slender, wavy stalk, from 2in. to Ain. long. 
Messrs. Berkeley and A. S. Wilson have named it 
P. postuma, but it seems very closely allied 
to P. sclerotiorum, Lib., and P. ciboroides, Fr. (see 
Fig. 99); and it is doubtful whether they are really 
; (en „Cups; c, Stalks; 
2 Penza — Sclerotium. 
: species- P. sclerotiorum causes disease in 
Turnips and Cabbages in Germany, forming sclerotia 
