Roridulaceae

Kevin Snively (ksnive@premier1.net)
Wed, 7 Aug 1996 19:07:00 -0700 (PDT)

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I'll be going to bed early tonight due to my work schedule and decided to
read & write for pleasure tonight instead of the ICPS. (I need a night
off)

> The situation is very similar in _Roridula_ but here the opposite is
> claimed, based on the single observation by F.E.Lloyd that the secretion
> of this plant is resinous and not mucilaginous

Herr Doktor
I hate to contradict you I'm most always wrong, butt.....

I went over what Lloyd said in his book "The Carnivorous Plants"
It looks to me like someone from Germany (How old are you?) tiped him off
to the earlier work by Marloth after Lloyd published something about CP in
1933. Lloyd to my eyes, is only reaffirming in 1934 what Marloth was
saying between 1903 and 1912. Obermeyer appears to have checked up on
Marloth's work in 1969 and in 1970 "Flora of Southern Africa Vol. 13"
does not offer any major contradiction. Ref. Page #202.

I've been putting Obermeyer's text on Roridulaceae in to HTML while
commuting to work on the bus, the text of which follows. (Slow work
on the bus) In preparing this for addition to the page on the Flora of
Southern Africa I could use a qualified editor to make sure there are
no Typo's. I can not spell. Would you do me the honer?
^^^^^^^^^^^^^^^^

For everyone else here is a not yet ready for the web preview. Sorry to
anyone who is bothered by the html.

krs

<Html>
<Head>
<Title>RORIDULACAE by A.A. Obermeyer</title>
</head>
<body>
<hr>
<center>
<h1><a name=Roridulaceae>RORIDULACAE</a></h1>
by A.A. Obermeyer
</center>
<hr>

Woody, glanduliferous, viscid shrublets with the leaves aggregated at
the tips
of the branches. Root-system poorly developed. Stem woody. Leaves
simple,
sessile, alternate, crowded near the ends of the branches, the lower soon
dropping
off, linear, yellowish green, the margins smooth or with long, filiform
teeth,
furnished with long immovable, gland tipped tentacles. Flowers
solitary or
aggregated in the axils of the upper leaves, forming loose apical racemes,
actinomorphous, pentamerous, bisexual; pedicles short or long. Sepals 5,
free or
fused at the base, imbricate, glanduliferous, persistant. Petals 5, free,
pink or
white, persistant or deciduous. Stamens 5, filaments erect, anthers with a
swollen
rounded base and 2 semi-free locules which open by apical pores, reversing
their
position when touched. Ovary 3-locular, each locule with 1-4 ovules
on an
axillary placenta; style simple, stigma apical. Capsule splitting
loculicidally;
seeds fairly large, warty or honeycombed, becoming mucilaginous when
moistened,
rich in endosperm.

A monogeneric family consisting of two species which are endemic in the
south-western Cape. Common name "vlieebos".

Marloth and Diels quite rightly excluded this genus from the
Droseraceae
preferring to place it in a family of its own. The differences between the
two Roridula species are extensive and Marloth believes that they
represent
relics of a much larger family since extinct.

Hutchinson combined the genus with the 2 divergent species of Byblis in
the
Australian family Byblidaceae. The affinities between these two genera,
from
areas so far appart, do not appear to be close enough to warrant their
inclusion
in one family.

Marloth was struck by the yellowish-green colour of this genus which
resembles
that of Endonema (Penaeaceae) an ancient Cape genus. This too, he thinks,
points
to their great age.

Works of general biological intrest are: "Some recent observations on
the
biology of Roridula" by R. Marloth in Ann. Bot. 17 : 151-157 (1903); and
"Further observations on the biology of Roridula L." by R. Marloth in
Trans.
Roy. Soc. S. Afr. 2, : 59-62 (1910-1912).

Marloth's researches on these two Cape species have brought to light
some
interisting facts. Previously the plants were regarded as insectivorous
(and
therefore placed under the Droseraceae) but Marloth discovered that the
secretion
from the immovable tentacles did not possess digestive properties, in fact
they
contained a compound which he at first believed to be akin to caoutchouc.
A
drop of fluid extracted by Marloth in 1902 and preserved in a paper
capsule
on a sheet at the National Herbarium (Marloth 2507) was still viscous in
1969.
However, in his article in the Trans. Roy. Soc. S. Afr. in 1910 he
compaired it
to a balsam.

According to Morloth's observations, a spider (crab spider, Synaema
marlothii
was seen to live on Roridula dentata. It's skin is not affected by the
viscid fluid.
It feeds on the insects caught by the plants. No spiders were seen to live
on
R. gorgonias.

Two species of Hemiptera (Capsidae), viz. Pameridea marlothii (found on
R. dentata)
and Pameridea roridulae (found R. gogonias) live on thees plants. With
their proboscis
they piercen the swelling at the base of the anthers in search of sugar.
This action
causes the young anther to swing around suddenly into an erect position
scattering
pollen on the insects. Marloth examined a number of these insects and
found pollen
adhering to their bodies.

In his Flora of Southern Africa, Vol. 2, 1 on p. 28, Marloth notes that
"the
root system of the plants is very poor. The young rootlets show a few
rudimentary
root hairs only near the apex while the older parts are bare but
surrounded by the
loose web of mycorrhiza". This could not be verified. Plants of Roridula
gorgonias
and R. dentata were examined by Dr. G. van der Westhuizen of the Plant
Protection
Research Institute in January, 1968, but no infection by a fungus could be
detected.


<hr>
<pre>
<h2>3138 <A name=Roridula>Roridula</a><a
href=#R.note>*</a></h2>
</pre>

Roridula L., Gen. ed. 6 : 567 (1746); DC., Prodr. 1 : 302
(1824);
Planch. in Ann. Sci. Nat. ser. 3, 9 : 79-90, 307-308 (1848); Sond. in F.C.
1 : 79
(1860); Diels in Pflanzenfam. ed. 2, 18a : 346 (1930); Phill., Gen. ed. 2
: 359
(1951). Type species R. dentata L.

<pre>
Ireon Burm.f., Fl. Cap. Prodr. 6 (1768).

Characters as for the family.

Leaves, at least the upper, dentate with long fine teeth; flowers on long
pedicels; petals persistent, c. 12 mm long; stigma only slightly
dilated;
a solitary ovule in each locule; shrubs up to 2 m tall; Tulbagh to
Calvinia. . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.
R. dentata

Leaves entire; flowers on short pedicels; petals paducous, c.15 mm. long;
stigma dilated; ovules 2-4 in each locule; shrublets up to 40 cm
tall;
Somerset West to Caledon. . . . . . . . . . . . . . . . . . 2.
R. gorgonias
</pre>

1. <A name=R.dentata>Roridula dentata</a> L., Gen. ed. 6
: 567 (1764);
Syst. Nat. ed. 13, 2 : 185 (1770); Lam., Ill. 1 : 141 (1823); DC., Prodr.
1 : 320 (1824);
Planch. in Ann. Sci. Nat. ser. 3, 9 : 307 (1848); Sond. in F.C. 1 : 79
(1859); Marloth in
Fl. S. Afr. 2, 1 : 26, t. 10a (1925); Diels in Pflanzenfam. ed. 2, 18a :
347, fig. 181
(1930); Rice & Compton, Wild Flow. Cape Good Hope 54 (1950). Type :
Cape, without
locality or collector, (LINN 284.1, 284.2).

R. verticillata Pers., Syn. 1 : 253 (1805), nom. sub. R.
dentata L.
R. muscicapa Gaertin. Fruct. 1 : 298, t.62 (1788). Type : Cape
(Herb. Banks, BM).
R. brachysepala Gand. in Bul. Soc. Bot. France 60 : 456 (1913),
partly. Syntypes:
Cape, Worchester and Tulbagh, Burchell 984: Ecklon 130 (P:
PRE); the other
cited specimens should be excluded for they belong to R. gorgonias
Planch.

Drosera roridula Thunb., Diss. Drosera 7 (1797). Type : Cape,
Thunberg
(UPS, holo.: PRE, microfiche).

Ireon verticillata Burm. f., FL. Cap. Prodr. 6 (1768); Roem.
& Schult.,
Syst. 5 : 436 (1819), sphalm. "Iridion verticillata Burm. f."

Woody shrubs up to 2 m. Stems brownish smooth with longitudinal
fisures.
Leaves crowded on short side branches, the lower early deciduous
and often short,
with entire margins; upper linear-subulate, up to 5 cm. long and 3 mm.
wide, margins
with widely spaced, alternate, assending, subulate pinnate, the apices
ending in
several long-stemmed tentacles bearing knob-shaped, apical glands exuding
a sticky
fluid; short to long tentacles and white, short to long, sparse to dense
pubescence
cover the upper surface of the lamina, lower more or less glabrous.
Flowers
on long hairy pedicels in the axils of the upper leaves or occasionally
forming a loose
apical raceme, the supporting leaves being reduced to bracts.
Sepals
linear-lanceolate, acuminate, 10 cm long, glandular-pubescent.
Petals
obovate, c. 12 mm. pink. Stamens on short filaments 3 mm. long,
erect,
anthers 3.5 mm. long, base swollen, black. Ovary ovoid, attenuate,
hairy,
style ending in a slightly broadened stigma; ovule pendulous, solitary,
attached
to an axillary placenta. Capsule hidden inside the persistent
floral parts,
woody, oblong, apiculate; seed oblong in outline, 5 mm. long, distinctly
honeycombed,
brownish-yellow, rough. Fig. 29 : 1.

Recorded from the mountains in the Tulbagh' Ceres and Clanwilliam
districts in damp
localities at altitudes of 900-1200 metres. Flowering
September-October.

Cape.-Ceres : Koude Bokkeveld, Witzenberg Vlakte, Esterhuysen
28402; near Citrusdal, near Sandfontein, Schlechter 10134;
Elandskloof Compton12509; between Nuwekloof and Elandskloof,
Drege s.n. (K); Michell's Pass, Cheadle 859; Olifants
River Mountains, "Vredelus", at eastern base of Schoongezicht Peak,
Esterhuysen 29680; Koude Bokkeveld, Boboskloof farm,
Rourke 661; (NBG). Clanwilliam : Cedar Mountains, Honingvlei,
bordering streams, Leipoldt 873; Koupoort, Esterhuysen
12109; Pakhuis Pass, Leipoldt s.n., Esterhuysen 3436;
Bidou Mountains, Wupperthal, Thode A2113. Tulbagh : above
Waterfall, Bolus 5162; MacOwan 950; Marloth
2507.

2. <A name=R.gorgonias>Roridula gorgonias</a> Planch. in
Ann. Sci.
Nat. ser. 3, 9 : 307 (1848); Sond. in F.C. 1 : 79 (1860); Marloth, Fl. S.
Afr. 2, 1 :
26. t.10b (1925): Diels in Pflanzenfam. ed. 2. 18a : 348 (1930). Type :
Cape, Caledon,
R viersonderend Mountains, Ecklon & Zeyher (CGE, holo.).

R. crinita Grand. in Bull. Soc. Bot. France 60 : 456 (1913).
Syntypes: Cape,
Zeyher 56 (P; PRE!); Swellendam, Ecklon & Zeyher
(CGE).

Shrublets up to 60 cm. high. Stems fairly stout with prominent
horizontal
leaf-scars, brownish, ending in racemes which die off but producing side
branches below
the old inflorescences. Leaves crowded at the ends of the
branches, the older
reflexed, younger erect; lamina linear, up to 12 cm. long and 5 mm broad,
tapering
gradually to a filiform tip, margin entire, beset with long-stemmed
tentacles tipped
with knob-shaped glands; upper surface with small tentacles and long white
setae; lower
surface glabrous but the raised midrib furnished with a row of short
tentacles.
Flowers aggregated into terminal racmes bearing 10-12 flowers on
short
bractiferous pedicels. Sepals linear-subulate, 15 mm. long, the
tip ending
in a tentacle, margin softly hairy. Petals ovate, 15 mm long,
apiculate, with
a dark base, deciduous. Stamens with the anthers opening by wide
slits.
Ovary glabrous with 2-4 ovules in each locule, style broadening
towards the
apex where it forms a wide, flat, papillate stigma. Capsule
narrowly ovoid,
1 cm., herbaceous; seeds angled, verrucose, 2.5 mm long, brown. Fig. 29 :
2.

Found in the Somerset West, Stellenbosch, Caledon and Swellendam
districts in moist,
mountaine areas at altitudes of 100-900 metres.

CAPE-Caledon : Stanford Mountains, Stoke 9502; Oudebos,
Riversonderend Mountains, Stoke 2154; Viljoens Pass,
Primos sub Marloth 13571, Hutchinson 1072 (K); Palmiet
River, Guthrie3765; Kogelberg, Grobler & Van der Merwe
709; Swartberg, Bolus s.n.; Klein River Mountains, Stoke
7052. Hermanus : Hermanus, summit Maanskynkop, Galpin 12839;
Vogelgat, Schlechter 9546; Somerset West : Sir Lowry's Pass,
Marloth 9289; Steenbras River Valley, Marloth 2508;
Hottentots Holland Mountains, western slope, Zeyher 56; above
Gordon's Bay, Stoneman 573

Regarding the type locality, it is apparent form the Ecklon &
Zeyher
Collections that the collectors did not distinguish betwwn the two
species.
Consequently specimens of both were distributed under "130", this locality
including
both the Tulbagh and Swellendam districts. Planchon was led to believe
that the type
came from Tullbagh but it must have come from the more eastern locality;
see Diels,
"Die Arten von Roridula L." in Notizbl. Bot. Gart. Berlin 10 :
283-285 (1928).


<hr>
<a name=R.note>*</a> The name Roridula refers to the dewy
(roridus)
appearance of the plant caused by the mucilage excreted by the
tentacles.

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