MOEPHOLOGY.
Yellow corollas frequently show streaks (P. striata) or patches {P. Oederi) of
red. These streaks are often conñned to the lip or occur on lip and tube; the
patches are usually restricted to the hood. Even when in general terms these markings
are specifically constant (P. Oederi), they may be altogether absent (VAE. heteroglossa), or
may involve the whole corolla (VAE. rubra). But similar markings not infrequently
appear as sports oa corollas that are normally concolorous. Thus P. longiflora in the
Eastern Himalaya has sometimes a dark red hood and beak, while both in Sikkiin and
in Northern Tibet it may have a purple lunule on each side of the central line of its
usually concolorous lip. On the other band, this species sometimes occurs with corollas
uniformly white, and in this case it might easily be mistaken for P. siphonmtha (which
also at times has white corollas), if too great reliance were placed on characters of colour
or attention not directed to the other diagnostic characters.
The variation of colour in normally red corollas differs somewhat, and consists of the
appearance of a greater or less amount of white. This white may appear in blotches
(P. farfuraeea, ñpho7iantha), but this is somewhat rare; and if so, these are confined to the
tube and the lip. The usual variation is that the tube, the base of the hood, and thu
centre of the lip become uniformly white, the lobes of the Hp, the hood proper, and the
beak remaiuing red (P. confertiflora, zeylanica). In some species indeed this disposition of
colour is the normal one (P. caTtiosa, conjmbosa, odontopliora), while, generally speakinir, the
tube in red corollas is paler in tint than are the lobes of the lip, and these in turn are
jmler than the hood. Finally, species with normally red corollas may have pure white
Howers {P. aÍ2>homntha), while species whose affinities are clearly with groups in which
red corollas normally prevail (P. albiflora amongst the Rostrataej may have white flowers
only.
The staminal insertion has been already discussed. The filaments are narrow and
ligulate with a mesial main nerve, and occasionally (P. bicornuta, ekphan'oides) with wavy
margins. The filaments elongate considerably in those species where the staminal
insertion is not carried upwards by the elongating tube. Both pairs of filaments may
be hirsute and equally so, or with the posterior pair less densely hairy than the
anterior; or only the anterior pair may be hirsute, the posterior pair being glabrous. On
r.lie other hand, all may be glabrous, but in no instance do we find the posterior
})air hirsute while the anterior pair are glabrous. The hairs may prevail throughout
the filament; more usually they are confined to the upper portion, and may or may not
involve the connective. Sometimes, besides being hairy above, they are villous at the
point of insertion (P. pectinata), and, very rarely, are villous only at tlie point of insertion
but glabrous elsewhere (P. ColUttii). The starainul hairs are very early formed, and
are present in the youngest buds, and this condition affords one of the most constant
and most useful diagnostic characters of the genus. The anthers are free and parallel,
are usually obtuse,'but may be sharply tailed (P. Kingii), andas a rule lie horizontally.
They may, however, have the tails inclined slightly upwards, and oftener still slightly
downwai-ds, only very rarely (P. Perrottelii) are the long axes of the anthers vertical.
The ovary is ovate or lanceolate, usually slightly oblique, and always with two
lóenles. The placentas are double and vertical, and are confined to the lower third or
fourth of the transverse septum. The ovules are amphitropous with usually a short
funicle, are normally some multiple of four, there being two rows on each placenta, and
vary from 4 in each locule (P. gihhera) to 56 in each locule (P. conjmhm). The style,
at first erect, curves backwards to approach the tube at the level of the limbus of the
STAMEN S - S E EDS . ^
oalvx Beyond this point it follows the curvature in succession of the tube, of the liood,
and if it be present, of the beak. As a rule the style is of uniform thickness,_ but m
e'snecies (P superla) it increases in thickness towards the stigma.' ihe stigma is
sub-capitate, generally (though rarely very far) exserted, but sometimes distinctly included
'iP lachnoalossa). The enlarging fertilised ovary detaches the corolla from the disc and
at the same time splits the tube upward» from the base in the middle line behind It
is rare however, for tlie corolla to be immediately caducous (P. exeeba) ; as a rule it
become's gradually extruded by the elongating capsule till the base is clear above the
mouth of the calyx tube. Then as a rule it either falls ofl or is blown away, but it is
b y no means unusual to find the tip of a ripened and dehiscing capsule still crowned
b y a withered corolla. , , , . . ^ . •
The capsule varies a good deal in the genus as a whole, but is very constant in
size and form within specific limits and often throughout natural gi'Oups of species. The
relative length of capsule and calyx affords a more useful character than that of calyx
and corolla tube. This is not alime because the capsule is much more constant than the
corolla tube, which is, as has been seen, rather variable, but because tlie teeth, to which
the variation of tLe calyx is principally confined, usually become in tlie fruit shrivelled
and loss conspicnoua, and because the enlarging capsule by eipanding tlie calyx tube
renders the limbus more easily discernible between the bases of the teeth. The usual
shapes of capsule are lanceolate or ovate-lanceolate, rarely sub-rhomboid {P. rex), and in
these cases with the apex oblique and in front of the middle hue; not infrequently, however,
the capsule may be ovate (P. triAogloisa, fijamntha), or rarely sub.globnlar (P. fms^is),
and in these cases with the apex erect and central. Its surface is smooth and variously
reticulated, and (except in P. frmlis, where the capsule is transparent and almost herbaceous)
its walls are of a firm consistence; it varies in colour (in herbarium specimens)
from pale tan to black. The capsule is persistent, being always found attachod to the
stems of a former season where these happen to be collected. The dehiscence is loculicidal,
but is confined to the upper third of the anterior and the upper half of the posterior
suture, the valves nearly always remaining coherent (even in specimens showing stems
of a second season) from the base to opposite the upper limit of the placental surfaces.
The seeds vary greatly throughout the genus in number, size, shape, colour, and
surface marldngs; in individual species, on the other hand, these characters are very
constant. In number they vary from 3—4 in each locule (P. (/ihbera) to 18 or 20
( P . dolicJmrhka)] in size from 0-6 X 0-6 mm. (P. fragilis) or 1-2 X 0'7 mm. {P. carnosa)
to 3-5 X 2'0 mm. (P. Obrln) or 4'25 X 2'0 mm. (P. pyctiantha)-, in shape from spherical
(P. fragilia), ellipsoid (P. Clarkei), egg-shaped and narrower at the lower extremity
(P. longijlm-a), egg-shaped and narrower towards the apex (P. gihhera), to nearly fusiform
( P . ciirvipes). In transverse section the seeds are usually rounded or ovoid, rarely triquetrous
(P. acMzorrhjmha). The hilum is indicated by a furrow, the upper portion of
which is often filled by a spongy crest which, though of different appearance and lighter
colour, is in real i ty only a modified portion of the testa developed from the coats of
the ovule where these surround the micropyle. At the lower extremity of the seed there
is also in many species what appears to be a distinct process. But this also merely
consists of testa, not even modified, and has no special structure. It is most obvious
where the testa is thin and closely adpressed to the albumen, and is not visible at all if