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Vol. JK, Sect. 2. (iuusd June 1906).

Hydrophyllaoeae ....





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Convolvnlaceae ...

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Sorophulariaoeae ...

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Orobanohaoeae ...



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No. 7.] [1906.


{Hevea brasiliensis, Muell. Arg.)

The Rise and Pall in Prices op the Forbst Product for
the past 30 years and op the cultivated form for
the past 4 years.

In the Kew Bulletin for 1898 a chart was published shewing
the average prices of fine Para rubber {Hevea braailiensis)^ for
the years i877 to 1898 inclusive, and in view of the constantly
increasing importance of the rubber industry it has been
considered expedient to bring this up to date. A graphical
writing should explain itself, and without entering on too great
detail it will be observed that the general tendency has been
an upward one, although some of the variations are rather remark-
able. At no period has the price remained fixed throughout any
particular year, the nearest approach to this occurring in 1897
with a range of 3d. only ; the greatest deviation from it in 1879
with a range of 2s. The figures, maximum, minimum, and
average, in all instances, are given minus fractions of a penny.

Some explanation is necessary in connection with the lines
for cultivated or plantation Para rubber, which so far
appears to have come exclusively from Ceylon and the Straits
Settlements. The history of the industry in respect of these
Colonies has been fully discussed in previous issues of the
BtiUetin, and it will, perhaps, be unnecessary here to do more
than point out that the plantation rubber, according to statistics,
first began to appear in marketable quantities in 1903, although
exports on a smaller scale from Ceylon were made in 1901 (Ceylon
Administration Reports^ 1901, part iv., p. H2, Roy. Bot. Gardens).
Samples had been submitted as early as 1882 from there {Kew
Bulletin, 1898, p. 255), and in 1898 from the Straits Settlements
{Kew Bulletin, 1898, p. 274; and 1899, p. 22). On this subject it

1375 Wt72 10/06 D & S 29 25934

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may also be of interest to quote the following letter from the
Straits' Agricultural Bulletin (Vol- ii., 1903, p. 193), which,
together with the accompanying chart, will give a fair idea as
to their relative positions and to the trade in general at that

date (1903).

" 36, Fenchurch Street,

" London, E.C.,
<• 7th April, 1903.

" Harold Tunnicliflfe, Esq.,

'* Atherton Estate, Port Dickson,
<< Straits Settlements.

" Dear Sm,

" We dnly received your favour of the 8th March with
sample of rubber grown from Para seed. There are Mr quantities
of similar rubber beginning to come from Oeylon and they find a
ready market. The sample which you send us seems to be of
very good quality, tho' perhaps a trifle * tacky ' which, however,
may be due to the way in which the sample has been sent and
may not be the case in bulk. In to-day's market, which is a good
one, we should think a parcel of this rubber would fetch from
4^. id. to is. 5d. per lb., and our idea of the immediate future of
the article, anyhow until next autumn, being a favourable one, we
don't think that a shipment on the basis of our valuation will lead
to disappointment.

• •••••

** (Signed) Hecht, Levis and E[ahn."

As shewing the improvement on the beginning referred to in
the above letter, it is stated that "the most remarkable development
in Ceylon Agriculture during 1905 was the planting of rubber,
under which there were at the end of 1905 some 40,000 acres as
compared with 11,000 in 1904 and 7,500 in 1903, and the value of
rubber exported in 1905 was Rs. 557,945 as compared with
Rs. 221,000 in 1904." (Colonial Report, No. 494, Ceylon, 1906,
p. 23.)

It remains to be seen how soon, and to what extent, the West
Indies, West Africa, and other Colonies that have taken up the
cultivation of this product, will meet the requirements of the

J. H. H.


{Mdcrosporium aolani^ Cooke. Syn., M. tomato^ Cooke.)

Symptoms indicating the presence of this disease are very
pronounced. In what may be termed a mild attack, which
usually manifests itself only after the haulm is nearly full-
grown, the leaves change to a sickly yellowish green colour and
afterwards curl up at the edges ; the haulm soon afterwards
becomes limp, and finally droops. If the course of the disease
is carefully followed it will be observed that the lowest leaves
are attacked first, the disease gradually ascending the haulm until
all the leaves are involved. When the haulm collapses there is

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nsnally no external evidenoe of the presence of the fungus, but
if the tissues are examined microscopically an abundance of
mycelium will be met with. When the haulm and leaves are
dead or nearly so, the fruit of the fungus appears in abundance ;
on the leaves it forms minutely velvety blackish-olive patches
of variable form and size, whereas on the haulm it appears
under the form of long thin streaks. The difference in superficial
appearance between the broadly effused patches on the foliage,
and the long narrow streaks on the stem, has led to the
supposition that two distinct parasites are present. The sup-
position is a mistaken one, only one parasite is present ; the
difference between the appearance on the leaves and stem
respectively is a matter of mechanics and not of species. On
the stem the fruit of the fungus can only break through to the
surface between the parallel rows of vascular bundles, hence
the long, narrow streaks ; whereas the arrangement of the veins
in the leaf admits of the fruit appearing in extended patches.

In an acute attack the haulm is stunted from the first, and
rarely attains to a length of six inches, the leaves also remain
quite small and are much curled. In such cases no new tubers
are formed. Sometimes the ** sprouts " are killed outright in the
youngest stage before they appear above-ground. In such an
instance if the ''set" is examined it will be found to be quite
firm and apparently practically unchanged.

It has already been explained elsewhere that '' leaf -curl " is
perpetuated from year to year by the presence of mycelium in
the tuber {Kew Bulletin^ 1906, p. 110; Joum. Board Agric.^
September, 1906). When a tuber infested with mycelium is
planted, the mycelium grows along with the stem and enters the
leaves ; it also passes into the young tubers. When a tuber is
only slightly infested with mycelium, it follows the course
indicated, and its further behaviour as to remaining in a
subordinate condition in the tissues of the potato plant, and
doing little harm beyond infecting the new tubers ; or whether
it assumes a rampant form and destroys the aboye-ground
portion of the potato plant, depends almost entirely on weattier

On the other hand when a tuber is badly infested with
mycelium it is often completely dead before it is planted. If
not quite killed it may produce the dwarfed growth already
described. As the fungus mycelium does not destroy the starch,
but only the proteid substance, it is practically impossible by any
superficial method to determine whether a tuber is killed or not.
This can only be determined by a microscopic examination.

Owing to the fact that the conidia of the fungus are only
produced on dead or dying plants, and mostly in the autumn, the
epidemic is not increased by healthy plants having their foliage
infected by the conidia produced on diseased plants, as in the
case with "potato disease" caused by Phytophthora infestans^
De Bary. Quite young shoots have been infected, late in the
season, with conidia obtained from dead plants of the same year,
but the infection remained local and did not extend backwards
down the haulm, hence the young tubers could not be infected
with mycelium.

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From the statements made it will be gathered that infection can
only take place through the tuber. This can be effected in two
ways ; from a previoasly diseased tnber that has been nsed as a
" set," or from conidia present in the ground. The latter method
implies the previous growth of a diseased crop on the same land. In
either case when a tuber once contains the hybemating mycelium
of the fungus, the probability is that its offspring will be infected
for all time, the mycelium passing from one generation to another.
This statement however is not absolute. Last year tubers obtained
from potatoes badly affected with ** leaf -curl " were planted in the
experimental ground adjoining the Jodrell Laboratory at Kew,
and every plant showed the disease in every part. The
tubers produced by this crop were planted again this year, and
although every plant is obviously diseased, one root bearing four
haulms has one haulm very badly diseased, the other three being
perfectly healthy. Another root with five haulms has two diseased,
the remaining three healthy. All the other plants are diseased
throughout. The probable explanation of this is that for some
unknown reason, the mycelium present in the tuber did not pass
up into the shoots that remained free from disease.

The blackish patches that appear on diseased leaves and haulms
consist entirely of conidia or reproductive bodies of the fungus,
which originate from the dense weft of mycelium present in the
tissues of the potato plant. The conidia are comparatively large,
dark coloured, and when mature are divided into several cells by
walls developed more or less at right-angles to each other. When
once mature these conidia will germinate readily during any
period of the year, provided the requisite conditions are present.
In a state of nature, however, it so happens that such conditions
are not forthcoming at all seasons, but only during that period
which coincides with the growth of young potato tubers. The
two factors necessary for the vigorous germination of conidia are,
a given temperature and the presence of moisture. A series of
experiments show that the minimum or lowest temperature at
which coinidia will germinate in a manner sufficiently vigorous
to effect inoculation is 47° P. This prevents the majority of
conidia produced on the dead leaves and haulms in autumn from
germinating until the following season. The optimum, or most
suitable temperature for germination is 64° F. The maximum,
or highest temperature for healthy germination is 78° F. The
rate of germination at the optimum temperature of 64° F. is twice
as rapid as at minimum or maximum temperature. In twelve
hours many very long, much branched germ-tubes are produced,
and within twenty-four hours numerous secondary conidia are pro-
duced on the germ-tubes. These secondary conidia are produced in
chains simulating the form-genus Alternaria, In cultures of
germinating conidia, when the food becomes exhausted, the
contents of the germ-tubes concentrate at intervals into small
masses which become surrounded by a thick wall, and are
practically chlamydospores or resting-spores, which can only be
induced to germinate after a period of rest. Such resting-spores
have germinated after having been kept in the laboratory for six
months in a perfectly dry condition, and it is quite probable that
such resting-spores may remain in the soil from one season to
another without losing their power of germination.

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The dependence on favourable conditions as to temperature and
other factors, influencing the germination and power of infection
of conidia present in the soil ; also the dependence on weatHer of
the relative growth of mycelium in an infected tuber, serve to
explain why the disease is much more prevalent during some
seasons than others, also why during certain seasons there is
practically no disease present.

Experiments prove that tubers can only be infected during the
earliest stage of growth ; when the tuber has reached the size of a
marble and a definite periderm or skin is formed, it is free from

Judged from a morphological standpoint the relationship of
the fungus causing ** leaf -curl " to that of another fungus —
Macrosporiuni tomato, Cooke, parasitic on cultivated tomatoes,
was some years ago indicated as follows : — ** This fungus is closely
allied to, if not identical with the Macrosporium causing black
stripe, or blotch on the tomato" (Text-book of Plant-diseases^
p. 323). Inoculation experiments have proved this supposition to
be correct. Conidia produced on a potato plant will infect a
tomato and mce versa. The discovery facilitates matters to the
extent of deleting one supposed parasitic entity, and also indicates
the danger of the disease passing from one crop to the other when
the two are growing in close proximity.

The practical deductions to be derived from the fore;?oing
remarks are as follows : —

Potato tubers for planting should be obtained from a district

free from disease.
Potatoes should not be planted, for a period of three years, on

land that has produced a diseased crop.
Diseased haulms should be collected and burned or deeply

buried. This is important, otherwise the land will

become infected.
Diseased tomato stems and fruit should be dealt with as

above, otherwise the potato crop may sufEer.


864. Ouarea Thompsoni, Spragtie et Hutchinson [Meliaceae] ;
ab affini &. Zenkeriy Harms, inflorescentia pyramidali recedit.

Arbor ramulis glabris 1 cm. diametro vel ultra. Folia 7-8-juga,
glabra ; petiolus circa 8 cm. longus, eemiteres, marginibus paullo
iniiexis ; foliola oblonga vel obovato-oblonga, rarius oblanceolata,
10-20 cm. longa, 4'5-7*5 cm. lata,apiceobtusa,interdumbrevissime
acuminata, nonnunquam retusa, basi rotundata vel obtuse cuneata,
chartacea, utrinque opaca, venis et venulis supra inconspicuis,
subtus prominulis, lateralibus utrinque 11-14 patulis vel satis
obliquis; petioluli 6-11 mm. longi, supra canaliculati. Paniculae
axillares, plures versus aplcem ramulorum dispositae, anguste
pyramidales, 12-30 cm. longae, rhachi puberula ; bracteae minutae,
depresso-deltoideae ; pedicelli 4-7 mm. longi, pubescentes. Calyx
cupularis, 3 mm. altus, 4 mm. diametro, paullo quinqueundulatus
potiuB qoam lobatus, extra pubescens, intus glaber. Petala 5

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vel 69 imbricata, oblonga, basin versoB angngtata, apice rotondata
Tel obtnsa, 8-10 mm. longa, circa 3 mm. lata, extra minute pnbes-
centi&9 intuB g^bra. Tvhus staminaUs glaber, medio YentricoBUB,
7-7*5 mm. longoB, apice 10-15-lobatas ; lobi obiongi, 1'25-1*5 mm.
longi, 0*5 mm. lati, apice breviter bifidi, lobnliB obtosiB ; antherae
10-15, cymbiformeB, tabo viz infra inciBaras BessileB, 1-1*25 mm.
longae, circa 0*5 mm. latae. Ovarium BCBBile, oblongum, 5 mm.
longnm, 1*5-2 mm. diametro, longe piloBom, 4-5-locnlare, locnlis
1 mm. Bupra bauin sitis, biovulatis, ovuliB inaequialte collateralibos
pendnliB, Bapra locnloB cavnm ; styloB 2-2*5 mm. longoB, glaber,
stigmate peltate glabro 1*75-2 mm. diametro. FrticttM desimt.

Southern Nigeria. Benin City, H. N. Thompson^ 16.

865. Oynmosporia deflexa, Sprague [Celastraceae] ; ab affini
Celaatro aWatOy N. E. Brown, foliis majoribus lanceolato-ovatia
pedicellis dnplo JongioribuB recedit.

Arbor mediocriB (fide Grenfell)^ vel magna (fide BurU-Davy).
Hamuli circa 20 cm. longi, inermes, leviter fiexnosi, tereteB, glabri,
Jnniores pallide glauco-virides, Bupeme compressi, aeniores
cinereo-corticati rugulosi, internodiiB 1-4 cm. longiB. Folia
Bolitaria, lanceolato-ovata, apice obtusisBima, basi cimeata, Bimpli-
citer vel snbdupliciter dentato-serrata, tenuiter coriacea, supra
pallide viridia vel glauco-viridia, venuliB prominulis crebre
reticulata, subtus albido-glauca venis satis prominentibus, venulis
quam supra minus conspicuis ; venae latei-ales utrinque 10-11 ;
lamina 7-14 cm. longa, 3*5-6 cm. lata ; petiolus circa 1 cm. longus,
supra excavatuB. Flores axillares, lO-SO-fasciculati, pentameri ;
pedicelli 15-18 mm. longi, 5-6 mm. supra basin conspicue arti-
culati. Sepala anthesi deflexa, ovato-oblonga, supra concava,
1-1*75 mm. longa, 1-1*25 mm. lata, submembranacea, apice vel
usque medium ± brunneo-lacerata vel denticulata. Petala anthesi
deflexa, elliptico-ovata, rotundata, subtus infra medium valde
concava, apice inflexa, 4*75-5 mm. longa, circa 3 mm. lata. Discus
annularis, 0*6-0*7 mm. latus. Filam^enta 1*5 mm. longa ; antherae
suborbiculares, circa 0*7 mm. diametro. Ovarium triloculare,
1*25 mm. altum ; stylus 0*5-0*75 mm. longus ; stigmata 3 crassa ;
ovula pro loculo 2 erecta. Capsula depresse trigono-globosa,
6-8 mm. diametro, stylo persistente apiculata 2-3-sperma, valvis
rigide coriaceis, minute elevato-punctatis. Semina castanea, arillo
incomplete, irregulariter lobato et lacerate minute crenulato.

Transvaal. Zoutpansberg : Woodbush, Qren/ellf 4 ; Ghrenfell
in Transvaal Colonial HerbaHum, 1142 ; Patata bosch No. 2013,
Burtt-Davy in Transvaal Colonial Herbarium.

According to Burtt-Davy, Q, deflexa is common in the Mist-belt
forest of the Houtboschberg (Zoutpansberg District) at altitudes of
between 1400 and 1500 m. It is there known as " Saflfraan-hout,"
on account of the yellow colour of its inner bark.

866. OymnoBporia condensata, Sprague [Celastraceae] ; affinis
Celastro polyacanthOy Send., cymis condensatis floribusque majori-
bus ab eo recedit.

Arbor parva. Hamulus unions exstans 30 cm. longus, spinis
validis armatus, subteres, glaber, pallide glauco-viridis, internodiis
0'7-2 cm. longis. Folia supra spinos faioiculata, oblamceolata vel

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augiiste oboTata, apice obtusa rotnndata vel paallo emarginata,
saepius mucronnlata, versus basin sensim angnstata, minute
glanduloso-serralata, chartacea, utrinque pallide glauco-viridia,
venis et yenulis supra occultis subtus prominulis, lateralibus
utrinque circa 5 ; lamina l*5-2'5 cm. longa, 6-8 mm. lata ; petiolus
2-3 mm. longus, supra ezcavatus. Cymi densissimi, e spinis orti.
Flores pentameri ; pedicelli 3-3*5 mm. longi. Sepala anthesi
patentia, suborbicularia, 0*5-1 mm. diametro, lacerato-denticulata,
supra leviter concava, submembrauacea. P&tala tandem patentia
vel paullo deflexa, elliptica vel ovato-elliptica, rotundata,
2*75-3*5 mm. longa, 1*75-2*5 mm. lata, minutissime denticulata.
Discus annularis, 0'3-0*4 mm. latus. Filamenta 1*75-2-25 mm.
longa, basi dilatata; antherae reniformes, 0*75 mm, diametro.
Ovarium triloculare, 0*75 mm. altum ; stylus brevissimus ;
stigmata 3, circa 0*5 mm. longa ; ovula pro loculo 2 erecta.

Transvaal. Olif ant's River, Hurley, 1.

867. CissuB adenopodus, Sprague [Ampelidaceae] ; a ceteris
speciebus sectionis Cyphostemmae, subsectionis Planchonianae
ootavae, pediceUis conspicue glanduliferis, inflorescentia ceterum
pilis ordinariis vestita recedit.

Planta herbacea, ope cirrhorum scandens. Radix tuberosa
(fide Dawe), Caulis teres (exsiccatus costatus), ut petioli et
petioluli cirrhique patule pilosus et pilis glandulosis paucioribus
vestitus. Folia trif oliolata ; petioli subteretes, 3-5 cm. longi ;
petioluli 4-7 mm. longi, medii quam latei*ales paullo longiores ;
foliola ovata, acute acuminata, grosse serrata, lateralia basi
inaequaliter rotundata vel subcordata, 5-8 cm. longa, 3-4 cm. lata,
terminale basi obtusum vel rotundatum, 7-10 cm. longum,
4*5-5*5 cm latum, utrinque setulosa, supra viridia venis in meso-
phyllo depressis (exsiccando prominuliij), subtus rubida venis
prominentibus (exsiccando paullo) ; venae laterales utrinque 5-6.
Stipulae falcato-lanceolatae, acutae, 7-10 mm. longae, circa 3 mm.
latae, extra pilosae. Panicula oppositifolia, plana, ambitu tri-
angularis, 3*5 cm. pedunculata, circa 10 cm. longa, vivide rubra,
patule pUosa, ramis altemis 0*5-1*5 cm. distantibus. Bracteae
inconspicuae. Pedicelli circa 4 mm. longi, pilis glanduloso-
capitatis paucis conspicuis et ordinariis brevibus inconspicuis
induti, post anthesin recurvi. Aldbastra circa 3 mm. longa, apice
pilosa. Calyx eupularis, 0*75-1 mm. altus, basi puberulus. Petala
oblonga, obtusa, apice 1-1*5 mm. cucuUata, 4 mm. longa, vix
1*5 mm. lata, cucullo rubro extra longiuscule piloso, ceterum
glabra viridia, anthesi valde defiexa. Stamina prima anthesi ad
Btylum appressa ; filamenta circa 3 mm. longa ; antherae late
ellipticae, 0*75 mm. longae. Ovarii segmenta 0*75 mm. longa ;
stylus 2*5 mm. longus.

Uganda. Busiro District, alt. 1200 m., Dawe, 224.

Roots of this species were collected by Mr. Dawe in the
Mufukamata Forest and sent to Eew, where the plant flowered in
the Succulent House in August, 1906. The young shoots and
leaves are coloured bright r^, and the species is in consequence
rather decorative ; the upper surface of the leaves soon becomes
green, but the stems and the lower surface of the leaves change

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but little in colour. G. adenopodus does not appear to be nearly
related to any Cissus hitherto described ; perhaps its closest
affinity is with (7. Buchananiiy Planch., which has, however, five
leaflets and a very glandular inflorescence.

Besides the ordinary and gland-tipped hairs mentioned in the
preceding description, a third kind is found on G. adenopoduSy
namely, "pearl-glands." They are present on the inflorescence,
usually near the base of the pedicels, on the under surface of the
young leaves, and on the outside of the stipules near the base.
The view generally adopted nowadays is that pearl-glands are
" food-bodies " for ants, at all events in many cases [see Penzig in
Atti Congr. Bot. Intemaz. 1892, p. 239 ; and Raciborsky in
Flora, vol. Ixxxv. 1898, p. 358].

868. Sohotia transvaalensis. Rolfe [Lieguminosae-Caesalpinieae] ;
affinis S. brtichypetaUze, Sond., sed caulibus juvenibus pubes-
centibus, foliorum rhachi anguste alata, foliolis minoribus sub-
membranaceis, floribus minoribus, petalis exsertis differt.

Caules juvenes pubescentes. Folia abrupte pinnata ; rhachis
anguste alata, 5-6 cm. longa ; f oliola 4-6-juga, brevissime petiolata,
elliptica vel obovato-oblonga, apiculata vel interdum emarginata,
submembranacea, glabra, 1*5-3 cm. longa. Stipula semicordata,
acuminata, 8 mm. longa. Paniculae axillares, pubescentes, circa
3 cm. longae, densiflorae. Bracteae brevissimae, truncatae. Flares
breviter pedicellati, coccinei. Calycis tubus brevis ; lobi obovati,
obtusi, circa 1 cm. longi. Petala anguste obovata, unguiculata,
circa 1*5 cm. longa. Stamina circa 2*5 cm. longa. Legunieti
oblongum, apiculatum, compressum, ligno^um, circa 8 cm. longum.
Seynina 3, obovato-oblonga, compressa, nitida ; testa reticulato-
venosa ; arillus latus, truncatus, circa 1 cm. longus, 1*2 cm. latus.

Transvaal. Barberton, P. P. Oranje.

869. Pentanisia Sykesii. Hutchinsoti [Rubiaceae-Enoxieae] ;
affinis P. Schweinfurthii, Hiem, a qua calycis tubo glabro, stipulis
et calycis lobis magis foliaceis recedit. •

Herha rhizomate ascendente lignoso, e basi ramosa, circa 26 cm.
alta, ramis subquadrangularibus infra stipulas linea pubescenti
notatis. Folia sessilia, lanceolata, basin versus angustata, glabra,
firma, apice acuta vel obtusa, 2'5-4 cm. longa, 0*5-1 cm. lata.
Vagina stipulafHs usque ad 3 mm. longa, lobis 3-5 linearibus
obtusis interdum subfoliaceis 3-10 mm. longis 0*5-2 mm. latis.
Gyma bipara, primum capitulif ormis, ramis mox elongatis. Galycis
tubus glaber, circa 2 mm. longus, lobis acutis admodum
inaequalibus, 1 vel 2 eorum foliaceis lineari-oblongis 5-9 .mm.
longis 1-1*5 mm. latis, ceteris subulatis multo brevioribus.
Gorollae tubus extra pubescens, fauce extra glabrata circa 1 mm.
diametro ; lobi 5, oblongo-lanceolati, 5 mm. longi, 2 mm. lati,
extra glabrati, intus minutissime pubescentes (fere papillosi).
Flares longistyli — Corollae tubus 11 mm. longus, fauce dense
barbata ; stamina inclusa, 2 mm. infra sinus inserta, filamentis 1 mm.
longis, antheris flavis 2 mm. longis ; stylus 15 mm. longus, lobis
stigmaticis 5 inaequalibus corollae tubum 4 mm. superantibus.

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