AN ENCYCLOPADIA 
OF HORTICULTURE. | 127 5 
Pilocereus continued. . 
P. Brunnowii (Brunnow’s). f. unknown. Stem erect, cylin- 
drical, many ribbed, 8 green, thickly beset with shining 
spots; ribs nine to twelve, vertical, rounded, uneven when 
young, later on pretty smooth. Prickles about thirteen, cen- 
tral one much the longest, surrounded in the 5 parts of 
the plant by long white hairs. Bolivia, 1870. See Fig. 151 (for 
which, as well as for Fig. 152, we are indebted to Herr Fr. Ad. 
Haage, jun., of Erfurt). 
P. Curtisii (Curtis’). f., tube olive-green, 2in. long, zin. thick, 
expanding with many imbricating segments; within this is a 
series of pale rose-coloured, ovate petals ; style deep rose-colour ; 
stigma of seven or eight rays. Spring and summer. Plant 3ft. or 
more high, 1 in. to Žin. in diameter, erect, straight or somewhat 
flexuous, eight to ten-angled, beset with little tufts of wool; from 
these arise a spreading cluster of aculei, and from a tuft of this 
description springs the flower. Grenada. Syn. Cereus Royeni. 
(B. M. 3125.) 
P. Dautwitzii (Dautwitz’s).* Stem oblong or fusiform, bright 
een; traversed from base to apex by twenty-one shallow ribs, 
earing closely-set tufts of small, white, spreading straight 
spines, and covered throughout, but more especially at the top, 
with a dense coating of long, white, cottony hair. Northern 
Peru, 1870. See Fig. 152. 
P. fossulatus (grooved). Stem erect, club-shaped, with ten 
to twelve obtuse angles; sutures undulated, with a depression 
above each areole; spines pale brown, the central one very 
Pilocereus—continued. 
grey hairs of an old man’s head. . . When young, the stems 
are — a 4 succulent, but, as they nit Mid, their tissue 
becomes with an extraordinary quantity of small, sand-like 
grains, hae 4 Fed os ot dime, Hot J less than from 60 to 80 
r cent. havin, n found in stems (‘ Treasury 
tany ”). na Tea and Guatemala. ; f Ad 
ö'Lr A synonym of Manicaria (which 
see). 
PILOSE. Covered with long, soft hairs; having the 
form of hairs. 
PILOSELLA. Included under Hieracium. 
PILOSIUSCULUS. Slightly hairy. 
PILULARIA (from pilula, a little ball or pill; 
alluding to the shape of the heads containing the repro- 
ductive organs). Pillwort. ORD. Marsileacew, A small 
genus (three species) of obscure little aquatic plants, in- 
habiting temperate Europe, Western Asia, Australia, and 
North America. Rootstock creeping under water. Leaves 
solitary, erect, setaceous. “Capsule globose, two to four- 
celled, two to four-valved at the top; cells each with a 
longitudinal, parietal placenta, on which are inserted 
Fig. 153, UPPER PORTION OF PLANT OF 
strong, lin. Jong, the outer ones ten to twelve, depressed ; 
8 an strong, with a tuft on the apex., h. probably 
20ft. A noble and very distinct, but scarce species. Peru (). 
(G. C. 1873, 197.) er ee 
P. Houlletii (Houllet’s).* fl. a kind of violet, with a suspicio: 
rose and a ae eda ies small, numerous, lanceolate, re- 
curved; tube short, smooth, with a few pointed, reddish-green 
scales, Stem strong, grey-green; ribs seven or eight; prickles 
nine, straw-coloured, central one longest. The younger parts of 
the plant are covered with a white felt. See Fig. 155. (R. H. 
gadas lindrical-ste l 
P. senilis (aged).* Old Man Cactus. “A eylindrical-stemmed 
plant, 1ft. 8 in height; but in Mexico, its native country, 
it attains a height of 20{t. to 25ft., with a diameter of 9in. or 
10in., and its fluted character gives it somewhat the appearance 
of an architectural column. The stem is divided into thirty or 
forty narrow furrows, with corresponding ridges, which are fur- 
nished, at very short distances, with tufts of white spines, sur- 
rounded by numerous long, fiexible, white hairs, resembling the 
PILOCEREUS HOULLETU, with Bud and Fruit (natural size). 
many pyriform, membranous sacs; sacs in the upper 
part of the cell full of microspores immersed in mucilage ; 
those in the lower part contain each one macrospore. 
Microspores globular, full of antherozoids. Macrospores 
ovoid, with an outer coat of prismatic cells, pierced 
by a funnel-shaped opening, through which an inner, 
glassy coat finally protrudes, In germination, a pro- 
thallus is developed at the top of the protruded portion 
of the inner coat of the macrospore, which bursts and 
frees it. After expulsion, an archegonium is formed on 
the prothallus, and fertilisation takes place by ; the 
contents of the microspore” (Hooker). P. globulifera 
is fonnd in damp meadows, among grass, especially where 
they have been overflowed with water during winter; 
it is widely distributed over England and Scotland, but 
