The family Rubiaceae in southern Assam with
special reference to endemic and rediscovered plant taxa
H.A. Barbhuiya1, B.K. Dutta 2, A.K. Das 3 &
A.K. Baishya 4
1 Botanical Survey of India, Eastern
Regional Centre, Shillong, Meghalaya 793003, India
2,3 Department of Ecology and Environmental
Science, Assam University, Silchar, Assam 788011,
India
4 Laban, East KhasiHills, Shillong, Meghalaya 793009, India
1 hussainbsi@yahoo.com (corresponding author), 2 bimankdutta@rediffmail.com,3 ajitkumardas2009@rediffmail.com, 4 akbaishya@rediffmail.com
Abstract: Analysis of diversity, distribution and
endemism of the family Rubiaceae for southern Assam
has been made. The analyses are
based on field observations in the three districts, viz., Cachar,Hailakandi and Karimganj,
as well as data from existing collections and literature. The present study records 90 taxa
recorded from southern Assam, four of which are endemic. Chassalia curviflora (Wall.) Thwaites var. ellipsoides Hook. f. and Mussaenda keenanii Hook.f. are rediscovered aftera gap of 140 years. Mussaenda corymbosa Roxb. is reported for the first time from northeastern India, while Chassalia staintonii (H.Hara) Deb & Mondal is reported as a new record for Assam.
Keywords: Assam, endemic, IUCN, new record,
rediscovery, regional assessment, Rubiaceae.
doi: http://dx.doi.org/10.11609/JoTT.o3117.5649-59
Editor: V. SampathKumar, Royal Botanic Gardens, Kew, UK Date
of publication: 26 April 2014 (online & print)
Manuscript details: Ms #
o3117 | Received 09 March 2012 | Final received 08 March 2014 | Finally
accepted 11 March 2014
Citation: H.A. Barbhuiya, B.K. Dutta, A.K. Das & A.K. Baishya (2014).The family Rubiaceae in southern Assam with special reference to
endemic and rediscovered plant taxa. Journal
of Threatened Taxa 6(4): 5649–5659; http://dx.doi.org/10.11609/JoTT.o3117.5649-59
Copyright: © Barbhuiya et al. 2014. Creative
Commons Attribution 4.0 International License. JoTTallows unrestricted use of this article in any medium, reproduction and
distribution by providing adequate credit to the authors and the source of
publication.
Funding: Self funded.
Competing Interest: The
authors declare no competing interests.
Acknowledgements: The first author is grateful to P. Singh, Director,
Botanical Survey of India (BSI), Kolkata and to A.A.
Mao, Scientist-E and Head of Office, BSI, Eastern Regional Centre, Shillong for facilities and encouragement. The authors also
extends their sincere thanks to Board of Trustees of the Royal Botanic
Gardens, Kew for providing the digital images of type specimens.
For figures, images, tables -- click here
The family Rubiaceae is widespread and occurs in all major regions of
the world except Antarctica and shows maximum proliferation in low to mid
altitude humid forests. The family
comprises 13,143 species falling under 611 genera by which it is the fourth
largest Angiosperm family (Davis et al. 2009). In India, it is represented by 551
species of which 67% taxa (365 spp.) are endemic (Sambamurthy2005). Kar& Panigrahi (1963) reported 118 species from
Assam and the North East Frontier Agency (present Arunachal Pradesh), whilst Chowdhury (2005) listed ca. 150 species of Rubiaceae from the state of Assam.
Southern Assam
(Barak Valley) is located between 24008’–25008’N
and 92012’–93015’E. The valley covers an area of 6,922km2and is surrounded by Dima HasaoDistrict and Jaintia Hill in the north, the Manipur
Hills in the east and the Mizoram Hills in the south. To the west the plains merge with the Sylhet plains of Bangladesh and the Indian state of
Tripura. At present the region is
divided into three administrative districts Cachar, Karimganj and Hailakandi. The 2,339km2 forest area comprises of 12
reserve forests and one wildlife sanctuary, i.e., ca. 34% of the total
geographical area of the valley. The drainage system of southern
Assam is fed by 18 major rivers and rivulets and Barak is the chief
river which flows in an east-west direction through the central part of the
valley. The annual average rainfall
and temperature ranges from 2500–4000 mm and 7.5–40 0C,
respectively; whereas, the relative humidity varies from 60–91 %.
The vegetation of
the region predominantly consists of tropical wet evergreen to tropical
semi-evergreen forest types (Champion & Seth 1968). Tropical wet evergreen type of
forest is prevalent in the northern and eastern slopes of southern Assam like Borail Hill Ranges, Lower Jiri Reserve Forest, Barak RF,
and Inner Line RF. The dominant
tree species of this type of forest are Actinodaphne obovata, Amoora rohituka, Dipterocarpus turbinatus, Duabanga grandiflora, Toona ciliata, Dysoxylum alatum, Melia azedarach,Mallotus nudiflorus, Mesua ferrea, Sterculia villosa, Quercus semiserrata, Callicarpa arborea, Castanopsis lanceifolia, Holarrhena antidysenterica, Schima wallichii, Macaranga indica, Bauhinia purpurea, Xerospermum glabratum, Mallotus albus and Ficus roxburghii.
Whereas tropical
semi-evergreen type of forest is prevalent in the southern and western parts of
southern Assam in Sonai RF, KatakhalRF, Singla RF, Badsha Tilla RF, Longai RF, Tilbum RF, Duhalia RF and Patheria RF. The dominant tree species of this type of forest are Schima wallichii, Saurauia roxburghii, Dipterocarpus turbinatus, Albizia procera, Gmelina arborea, Lagerstroemia speciosa, Macaranga denticulata, Mallotus nepalensis, M. roxburghianus, Phyllanthus emblica and Ficus bengalensis.
Materials and Methods
Field surveys were
conducted from 2010 to 2013 in 2,339km2 forest area, to assess the
diversity, distribution, endemism and threats to the family Rubiaceaein different parts of southern Assam, particularly in reserve forests and
wildlife sanctuaries. This was
supplemented with a literature study of peer-reviewed papers, monographs and
floras, followed by a study of the herbarium specimens housed at Botanical
Survey of India, Eastern Regional Centre, Shillong(Assam). Digital images of type specimens were
obtained from the Royal Botanical Gardens, Kew (UK) to confirm the identity of
the species. Species distributions
were plotted using Google Earth v.6.1.0.5001 (www.earth.google.com). Extent of Occurrence
(EOO) were calculated by drawing a minimum convex polygon and areas were
worked out by using the software GE Path v. 1.4.6 (Sgrillo2012). Similarly Area of Occupancy
(AOO) was calculated by the sum of the occupied isometric grid squares of size
20km2 (Image 1B).
The regional taxa of
southern Assam were then subjected to two stepassessment procedure: In step one, criteria B & D (IUCN 2001), were applied
to the selected regional population of the selected taxon, resulting in a preliminary
categorization. In step two, the
existence and status of any conspecific populations outside the region that may
affect the risk of extinction within the region was investigated either through
field visit or based on information from herbarium data and published regional
floras. If the taxon was found
endemic to the region, the Red List category defined by the criteria was
adopted unaltered and if on the other hand, conspecific populations outside the
region were judged to experience a “rescue effect” to the target population,
the global assessment was downgraded by one step to fit the IUCN regional Red
List guidelines (IUCN 2003), such as changing the category
from Endangered (EN) to Vulnerable (VU) or from VU to Near Threatened (NT).
Taxa that have been up- or downgraded in the regional Red List is clearly indicated by a dot after the category.
Taxa falling under
the IUCN Red List Criteria are dealt in detail with - synonyms if any,
description, phenology, distribution and specimen(s) examined as well as their
status, and criteria for determining the status. Materials cited in Table 1 have been
seen and are deposited in the herbarium of Botanical Survey of India, Eastern
Regional Centre (Assam), unless
otherwise stated. Digitalized specimens are cited along with their barcodes.
Results and Discussion
A total of 90 taxa
are recorded in the present study (Table 1), of which genera Ixora, Ophiorrhizaand Psychotria have a maximum number with
seven taxa each, followed by Oldenlandia with six taxa, Mussaenda with five taxa, Chassalia and Lasianthuswith four taxa each, Tarenna andUncaria are represented by three taxa each andCephalanthus, Leptomischus,Mitragyna, Morinda, Mycetia, Neonauclea and Prismatomeris are represented by two species each. Whereas other genera, viz., Acranthera, Aidia, Argostemma, Benkara, Canthium, Catunaregam, Ceriscoides, Dentella, Discospermum, Gardenia, Hedyotis,Hymenodictyon, Hyptianthera,Metadina, Meyna, Myrioneuron, Nauclea, Neolamarckia, Nostolachma, Oxyceros, Paederia, Pavetta, Psydrax, Richardia, Saprosma, Silvianthus, Spermacoce, Spiradiclis, Tarennoidea,and Wendlandia are represented by only one
taxon each. Of these, 14 taxa,
representing 16%, are found to be threatened andcategorized under various IUCN Categories (one probably Extinct, one Regionally
Extinct, two Critically Endangered, five Endangered, three Vulnerable and two
Near Threatened) of which four taxa are endemic to northeasternIndia. Leptomischus modesta (Hook.f.) Deb is endemic to Cachar District; whereas Chassalia curviflora (Wall.) Thwaites var. ellipsoides Hook. f., Mussaenda keenanii Hook. f. and Leptomischus wallichii (Hook.
f.) H.S. Lo are restricted to Assam and Meghalaya only. Mussaenda corymbosa Roxb. is reported for the first time from northeastern India and Chassalia curviflora (Wall.) Thwaites var. ellipsoides Hook.
f. and Chassalia staintonii (H.Hara) Deb & Mondal are reported for the first time from Assam
based on our collections. Chassalia curviflora var. ellipsoides and Mussaenda keenanii are rediscovered after a gap of ca. 140 years;
present collections of both the taxa also constitute their second authentic
collection after type.
Enumeration of threatened and endemic taxa
Acranthera tomentosa Hook.f.,
Fl. Brit. India 3: 92. 1880; Kanjilal et al., Fl. Assam 3: 48. 1939.
Epiphyte,hirsutely tomentose. Stem stout. Leaves elliptic or oblanceolate, 10–25 × 5.2–7.5 cm, acute
at apex, hirsute; petiole 2–2.5 cm long,
hirsute. Flowers bluish, in subterminal bracteate cymes. Calyx tube oblong;
lobes 5, linear-lanceolate, 1.5–2.5 cm long. Corolla villous; tube funnel-shaped, 3.5–4 cm long;
lobes 5, short, rounded. Stamens 5, included; filaments filiform;
anthers cohering into a tube, pointed and spurred at their tips. Ovary fusiform,
1-celled; ovules numerous, on two parietal 2-lamellate placenta; style filiform; stigma clavate,
furrowed. Berry ca. 3.8cm long with persistent calyx
lobes.
Flowering & Fruiting: July–October.
Distribution: India [Assam (Cachar), Arunachal
Pradesh, Meghalaya, Nagaland]; Bangladesh.
Specimen examined: Nil.
Global Red List Category: Vulnerable (Walter & Gillett 1998).
Regional Red List Category and Criteria: The species was collected by
R.L. Keenan from Cachar District of Assam more
than 140 years ago. During the
present study the entire southern Assam was surveyed, but it could not be
located. Therefore, following IUCN
Red List Categories and Criteria (IUCN 2001, 2003), it has been categorized as
Regionally Extinct (RE).
Chassalia curviflora (Wall.) Thwaites var. ellipsoides Hook. f., Fl. Brit. India 3: 177. 1880;
Deb & B. Krishna in Bull. Bot. Surv. India 24: 223. 1982. (Image 2(A)).
Shrub,upto 1.5m high. Leaves
broadly elliptic-lanceolate, 10–18 ×
3–6 cm, membranous, acuminate at apex, sub-acute at base, glabrous; lateral nerves 7–12 pairs, prominent on
lower surface; petiole slender, 1–2 cm long. Stipules
deciduous, deltoid, 2.5–3.5 mm long. Inflorescence
terminal cymes, 3–5 cm long. Pedicels short. Calyx tube 3–4 mm long, whitish;
lobes 5, pinkish, short deltoid. Corolla pinkish-white outside; tube 1.8–2.3 cm long, curved,
yellow inside; lobes 5, triangular, 2–3 mm long, incurved, white inside.
Fruits blackish, ellipsoid, ca. 10 × 7 mm, smooth.
Flowering & Fruiting: April–November.
Distribution: India [Assam (Cachar-present
record), Meghalaya], endemic to northeastern India.
Specimen examined: 567 (Assam),
25.iv.2011, Assam, Cachar, BorailWildlife Sanctuary, West Block, Near Malidar, coll.
H.A. Barbhuiya.
Global Red List Category: Not Evaluated.
Regional Red List Category and Criteria: The taxon was known only from its type
collection and the present collection is made after 140 years. Extent of occurrence is estimated to be ca.
40km2 (Criteria EN B1<5,000km2); The area of occupancy is calculated to be ca.
20km2 (Criteria EN B2<500km2), while there is a
continuous decline in area of occupancy due to slash-and-burn cultivation and
tree felling (Criteria EN B2b(ii)). Following IUCN Red List Categories and Criteria
(IUCN 2001), this taxon has been classified as Endangered (EN). As there is no
possibilities of rescue from neighboring regions, hence there is no
change to the initial assessment.
Note: This taxon was first described by Hooker (1880) on the basis of a collection made by
C.B. Clarke in 1872 from Jarain area in Jaintia Hills of Meghalaya. Thereafter this variety was not reported to be collected by anyone. Hence, the
present collection made after 140 years is a new record for the state of Assam.
Chassalia staintonii (H.Hara) Deb & Mondal in J. Jap. Bot. 57(5): 160. 1982; S.N. Das &
S.C. Roy in J. Econ. Taxon. Bot. 5(2): 473. 1984. Ophiorrhiza staintonii H.Hara in J. Jap. Bot. 52(12): 358. 1977. Image 2(B).
Erect shrub, ca. 1m tall. Leaves oblong-lanceolate, 16–24 × 3.6–5.2 cm, glabrous, base cuneate, abruptly
acuminate at apex; lateral nerves 11–14 on either side of midvein; petiole 1.5–3 cm long. Stipules
ovate-triangular with bifid apex. Inflorescence terminal
or axillary, many flowered cymes. Flowers whitish-pink, 5-merous. Calyx 0.5–1 mm
long, with prominent nerves; lobes 5, subulate. Corolla tubular, 12–15 mm long; lobes 5, ca. 3 mm long
with incurved apex. Stamens 5; filaments 2–3 mm
long; anthers 3–4 mm long. Ovary 2-locular, 1-ovule in each locule;
style 5–15 mm long; stigma bifid.
Flowering & Fruiting: May-November.
Distribution: India [Assam (Cachar-present
record), Sikkim, West Bengal]; Nepal.
Specimen examined: 701 (Assam),
08.x.2011, Assam,Cachar, Borail Wildlife
Sanctuary, West Block, Near Kalaincherra, coll. H.A. Barbhuiya.
Global Red List Category: Not Evaluated.
Regional Red List Category and Criteria: The area of occupancy is ca. 505km2 (Criteria
VU B2<2,000 km2), currently known from about six locations
(Criteria VU B2˂10), while there is a continuous decline in area of
occupancy due to slash-and-burn cultivation and tree felling (Criteria VU B2b(ii)). Following IUCN Red List Categories and Criteria
(IUCN 2001), this taxon has been classified as Vulnerable (VU). As there is arepossibilities of rescue from neighboring regions,
hence there is no change to the initial assessment.
Note: This species was first described by Hara (1977) as Ophiorrhiza staintonii on
the basis of a collection made by J.D.A. Staintonfrom Sikkim and easterm Nepal in 1966 and 1971
respectively. Das & Roy (1984) reported this species from Jalpaiguri District of West Bengal. It is reported here for the first time from Assam.
Ixora malabarica (Dennst.) Mabb. in Taxon 26: 539. 1977; T. Hussain & S.R. Paul in J.
Econ. Taxon. Bot., Addit.Ser. 6. 144. 1989. Chiococca malabarica Dennst., Schlüssel Hortus Malab. 37. 1818. Ixora lanceolaria Colebr., Fl. Ind. 1: 397. 1820. Image 2(C).
Small
tree, ca. 6m tall. Branches slender, pendulous. Leaves linear-lanceolate,
20–22 × 3.5–4.5 cm, acuminate at apex, somewhat glaucous above, pale beneath; lateral nerves usually
14–20 pairs; petiole short 0.8–1.3 cm long. Stipules adpressed, lanceolate, 6–7 mm
long. Bracts supporting inflorescence sessile, ovate, 2–2.5
× 1.2–1.5 cm, sub-acute at apex, cuneateat base. Cymes peduncled, trichotomous, pendulous, terminal panicle brachiate,
pubescent; bracts linear-lanceolate. Pedicels ternate,
1–2 mm long, pubescent especially at base. Flower not seen. Fruits greenish turn to reddish, globose, 5–8 × 9–10 mm, smooth, crowned
with subulate erect calyx teeth.
Fruiting:
June.
Distribution: India [Assam (Cachar),
Meghalaya, West Bengal, Maharashtra, Karnataka, Tamil Nadu, Goa, Kerala];
Philippines?
Specimen examined: 919 (Assam), 04.vi.2012, Assam, Cachar,Borail Wildlife Sanctuary, East Block, Nimatra Pahar, coll. H.A. Barbhuiya.
Global Red List Category: Vulnerable (IUCN 2012).
Regional Red List Category and Criteria: The Extent of occurrence is estimated to be
ca. 25km2 (Criteria EN B1<5,000km2). The area of
occupancy is calculated to be ca. 11km2 (Criteria EN B2<500 km2)
and there is only one known locality (Criteria EN B1a≤5), while there is a
continuous decline in area of occupancy due to encroachment of National Highway
54 (Criteria EN B2b(ii)). Following IUCN Red List
Categories and Criteria (IUCN 2001), the species has been classified as
Endangered (EN). As
there is no possibilities of rescue from neighboring
regions, hence there is no change to the initial assessment.
Ixora rangonensis Bremek. in Indian Forester 85: 374. 1959; Barbhuiyaet al. in Taiwania 57(4): 413. 2012. Image 2(D).
Shrub
up to 1m high. Leaves oblanceolate, 20–29 × 8–9.5 cm, cuneate at base, caudate at apex, caudaca. 2.5cm long, entire, glabrous on both sides;
lateral nerves 11–13 pairs; petiole 1–1.2 cm long. Stipules linear-triangular, ca. 1.5cm long. Bracts supporting inflorescence sessile,
ovate, 4–4.4 × 1.8–2.1 cm, base cordate,
apex acuminate, nerves 8-9 on either side of midrib. Inflorescencecymose, ca. 10cm long, numerous flowered, peduncle 6–8
cm long, pubescent; bracts linear-lanceolate, 5–6
mm long, pubescent. Flowers sessile to pedicellate; pedicels to 2mm long, hispid. Calyx tube ca. 2mm long; lobes 4, light brown, ovate, 1–2 mm,
pubescent. Corolla white, tube 20–25 mm long, glabrous; lobes 4, oblong, 4.5–5 × 1–1.2 mm,
rounded at apex. Stamens
4, 0.6–1 mm long, glabrous; anthers sub-basifixed. Ovary 2-celled, one ovule in each locule;
style slender, as long as corolla tube. Fruit not seen.
Flowering: April–May.
Distribution: India [Assam (Cachar)];
Myanmar.
Specimen examined: 659 (Assam),
09.v.2011, Assam,Cachar, Borail Wildlife
Sanctuary, Kalain Range, Near Kalaincherra,
coll. H.A. Barbhuiya.
Global Red List Category: Not Evaluated.
Regional Red List Category and Criteria: The
Extent of occurrence is estimated to be ca. 15km2 (Criteria CR
B1<100km2); Thearea of occupancy is estimated to be 8km2 (Criteria CR B2˂10km2),
known to exist at only a single location (Criteria CR B2a). The population size is estimated to
number less than 10 individuals and so far only one plant was seen (Criteria CR
D˂50 mature individual), while there is degradation of the habitat
(Criteria CR B2b(iii)) due to slash-and-burn
cultivation and tree felling. Following the IUCN Red List Categories and
Criteria (IUCN 2001), this species has been classified as Critically Endangered
(CR). As
there is no possibilities of rescue from neighboring
regions, hence there is no change to the initial assessment.
Leptomischus modesta (Hook. f.) Deb in Phytotaxonomy 1: 16. 2001. Keenania modesta Hook.f., Fl. Brit. India 3: 101. 1880; Kanjilal et al., Fl. Assam 3: 50. 1939.
Low
sub-herbaceous herb; branches without spongy swollen corky bark. Leaves opposite, elongate-lanceolate,
15–31 × 3.8–7.6 cm, abruptly acuminate, membranous, without
marginal stalked glands, puberulous beneath; lateral
nerves 15–20 on either side; base narrowed into petiole that is
2–2.5 cm long. Stipules somewhat recurved, membranous,
entire, 1.3–2.5 cm long without marginal stalked glands, Inflorescence in
terminal heads. Heads globose,
nodding, ca. 2.5cm. Peduncle
short. Flower sessile, heterostylous. Calyx 5 or 6-lobed,
ca. 0.7cm, longer than corolla. Corolla 5-lobed; tube
inflated, glabrous, throat with a ring of stiff
hairs. Stamens 5. Ovary 2-loculed, ovules 8.; style
short; stigmas 2, flat. Fruits not seen.
Flowering: April.
Distribution: India [Assam (Cachar)],
Endemic.
Specimen examined: Nil.
Global Red List Category: Not Evaluated.
Regional Red List Category and Criteria: The species is presumed to be Extinct (EX)
because an exhaustive survey in the type locality by D.B. Deb in October 1995
(Deb 2001) and by the authors from 2010–2013 to relocate the plant in its
type locality or anywhere in the Barak valley region proved futile. The type specimens were collected before
the establishment of tea gardens, which might have been the cause of its
extinction.
Leptomischus wallichii (Hook.f.) H.S. Lo in Acta Phytotax. Sin. 31: 275. 1993. Polysolenia wallichii Hook.f., Gen. Pl. 2: 68. 1873 & Fl. Brit. India 3: 94.
1880; Kanjilal et al., Fl. Assam 3: 49. 1939. Indopolysolenia wallichii(Hook. f.) Bennet in Indian Forester 107: 437. 1981.
Erect glabrous undershrub. Stem cylindric,
woody, simple or branched, glabrous or pubescent
above. Leaves lanceolate, 7.6–12.7 cm long,
acuminate, pubescent; nerves slender; base narrowed into a petiole,
0.5–2.5 cm long. Stipules 0.7–1.3 cm long. Flowers in solitary terminal peduncled heads, ca. 1.2 cm diam. Peduncle
0.7–2.5 cm long, slender, pubescent; bracts few, irregular, ovate or
linear-oblong ca. 0.4×0.3 cm. Flowers subsessile,
5-merous; pedicel up to 0.2cm, pubescent; hypanthium ca. 0.2×0.2
cm, obovoid, pubescent. Calyx-tube
short; lobes 5, broadly ovate. Corolla tube 2.2–3 cm long,
slender, pubescent outside, villous inside; lobes 5, ca. 0.2×0.1
cm, ovate-triangular, acute at apex, pubescent. Stamens 5, attached
at middle of corolla tube; filaments ca. 0.2cm, stout, glabrous; anthers ca. 0.2cm, dorsifixed,
2-loculed, pubescent. Ovary
2-loculed; ovules many, on peltate placenta; style filiform; stigma short, dilated; Capsules hemispherical,
0.3–0.4 × 0.3–0.5 cm, membranous, pubescent;seeds many, obovate-triangular, sparsely pubescent.
Flowering & Fruiting: June–December.
Distribution: India [Assam (Cachar),
Meghalaya], Endemic.
Specimen examined: Nil.
Global Red List Category: Rare (Walter & Gillett, 1998).
Regional Red List Category and Criteria: The Extent of occurrence is estimated to be
ca. 35km2 (Criteria EN B1<5,000km2); The area of occupancy is calculated to be ca.
15km2 (Criteria EN B2<500km2), known to exist from two
locations (Criteria EN B2a≤5), the area of occupancy is rapidly decreasing due
to slash-and-burn cultivation (Criteria EN B2b(ii)).
Following IUCN Red List Categories and Criteria (IUCN 2001), the species has
been classified as Endangered (EN). As there is no possibilities of
rescue from neighboring regions, hence there is no change to the initial
assessment.
Notes: Leptomischus wallichii (Hook.f.) H.S. Lo
was established by Hooker in 1873 as Polysolenia wallichii on the basis of a collection made by W.
Gomez from Khasia Mountains ,in the mean time R.L. Keenan also collected the plant from CacharDistrict of Assam. Later in 1968, Balakrishnan collected the plant from Sohha-Dawkiarea of Meghalaya.
Mussaenda keenanii Hook.f., Fl. Brit. India 3: 87.
1880; Kanjilal et al., Fl. Assam 3: 45. 1939. Image 2(F).
Erect robust
undershrub; stem greenish-white with thick coating of cork, which splits
longitudinally. Leaves obovate or broadly ovate,
10–30 × 5–15 cm, entire, abruptly acuminate, base narrowed
into petiole, subcoriaceous, densely tomentose beneath; lateral nerves 15–18 on either
side, sub-parallel, very prominent underneath; secondary nerves more or less
sub-parallel; petiole 0.5–2.5 cm long, stout. Stipules broadly ovate acuminate. Cymes, 5–7.6 cm
in across, almost capitate. Calyx 5-parted;
teeth filiform ca. 1.3 cm long, persistent. Corolla
ca. 2.5 cm, glabrous, tube slender; lobes 5, small,
deep orange, ovate-lanceolate, acuminate. Berry whitish, succulent.
Flowering & Fruiting: August–January.
Distribution: India [Assam (Cachar, Karimganj), Meghalaya?], Endemic.
Specimen examined: 112269 (Assam),
19..viii.2013, Assam, Karimganj,Patheria R.F., coll. H.A. Barbhuiya.
Global Red List Category: Not Evaluated
Regional Red List Category and Criteria: The extent of occurrence is calculated to be
ca. 50km2 (Criteria CR B1<100km2); area of occupancy
is estimated to be ca. 2.2km2 (Criteria CR B2<10km2),
currently known to exist from a single location (Criteria CR B2a) and the area
of occupancy is decreased due to the establishment of Gopal Tilla T.E., Kalain, Cachar, Assam (Criteria CR B2b(ii)). Following the IUCN Red List Categories
and Criteria (IUCN 2001), this species has been classified as Critically
Endangered (CR). As
there is no possibilities of rescue from neighboring
regions, hence there is no change to the initial assessment.
Note: This taxon was first described by Hooker (1880) on the basis of a collection made by
R.L. Keenan in 1873 from Gopal Tillain Cachar District of Assam. Thereafter there are no reports that
this species has been collected by anyone. Though, Kanjilalet al. (1939) in “Flora of Assam” mentioned its occurrence from Nongkhlaw area in the Khasi Hills
of Meghalaya, no herbarium specimen has been found deposited in any herbaria. Hence, the present collection
constitutes its rediscovery after 140 years and may also constitute its second
authentic report after its type collection.
Mycetia mukerjiana Deb
& R.M. Dutta in Indian Forester 91: 272. 1965;
S.C. Das & M.A. Rahman in Bangladesh J. Bot.
39(2): 218. 2010. Image 2(G).
Small shrub. Leaves
broadly elliptic, 25–27.5 × 7.5–9 cm, entire, acuminate,
membranous glabrous; lateral nerves 15–20 on
either side, alternate, subparallel; petiole 2–3
cm long. Inflorescence on leafless nodes. Flowers pedicellate, bisexual, regular,
ca. 10 mm long; pedicel ca. 4mm, stout. Calyx tube short, hemispheric; lobes 5,
persistent, chartaceous, 8–11.2 × 2–2.5
mm, lanceolate, acuminate, distinctly veined, scatteredtomentose. Corolla yellow, fleshy, tube slightly
longer than calyx lobes; teeth 5, short, reduplicate valvate,hispidulous at back, long pubescent within. Stamens
5, epipetalous, included within tube; filaments about 4–5 mm, flattened,
adhering to corolla tube, slightly free above, villous below; anthers oblong
ca. 3mm long, dorsifixed, puberulous,
2-lobed; lobes parallel, longitudinally dehiscent. Carpels 2,syncarpous; ovary inferior, 1.5–2 mm long,
hemispheric, hispidulous, 2 chambered. Fruits
small hemispheric berry, 2 chambered; seeds blackish minute, angled.
Flowering & Fruiting: August–December.
Distribution: India [Assam (Cachar, Lakhimpur), Mizoram, Nagaland]; Bangladesh.
Specimen examined: 778 (Assam),
10.xi.2011, Assam, Cachar, BorailWildlife Sanctuary, West Block, Kalain Range, 15 No. Hill, coll. H.A. Barbhuiya.
Global Red List Category: Indeterminate (Walter & Gillett 1998).
Regional Red List Category and Criteria: The area of occupancy is calculated to be ca.
502km2 (Criteria VU B2<2,000km2), currently known to
exist in 5–6 locations (Criteria VU B2a≤10). The area of occupancy is rapidly
decreasing due to slash-and-burn cultivation (Criteria B2b(ii)). Following the IUCN Red List Categories
and Criteria (IUCN 2001), this species has been classified as Vulnerable
(VU). As there is
no possibilities of rescue from neighboringregions, hence there is no change to the initial assessment.
Nostolachma khasiana (Korth.) Deb & Lahiriin Bull. Bot. Surv. India
17: 162. 1975. Lachnastoma khasiana Korth., Ned. Kruidk. Arch. 2(2): 202.
1851. Coffea khasiana(Korth.) Hook.f., Fl. Brit. India 3: 154. 1880; Kanjilalet al., Fl. Assam 3: 74. 1939.
Shrub,
up to 2.7 m high; young twigs pubescent. Leaves oblong or elliptic-lanceolate,
6.5–12 × 2–3.8 cm, caudate-acuminate, sinuate, glabrous above; lateral nerves 6–8 pairs; petiole
short, 0.5–0.6 cm long, stout pilose. Stipules subulate from base, ca. 0.7cm long. Flowers ca. 0.6cm
long, many in axillary dense much branched capitulate pubescent cymes. Calyx ca. 0.12 cm long; teeth 4, pilose,
acute. Corolla green in bud ultimately orange; tube ca. 0.5cm long;
throat villous; lobes 4, triangular, ca. 0.12cm long. Stamens 4, fixed at
throat of corolla tube; filaments short. Ovary 2-celled with one pendulous ovule in each surmounted by an annular
fleshy disk; style short; stigma deeply bifid; lobes linear. Drupe globose, ca. 7×5 mm, crowned by persistent calyx
teeth; seeds ventrally concave.
Flowering & Fruiting: April–February.
Distribution: India [Assam (Cachar, Goalpara-Guma R.F., Lakhimpur-DullungR.F., Sibsagar), Manipur, Meghalaya, Mizoram,
Tripura, Nagaland, Arunachal Pradesh]; Bhutan; Myanmar.
Specimens examined: 74121 (Assam),
23.ix.1978, Assam, Cachar, Mohankhal-Barunkhal,
coll. R.B. Majumdar; 84268 (Assam), 19.xi.1983, Lailapur, R.B. Majumdar.
Global Red List Category: Not Evaluated.
Regional Red List Category and Criteria: The area of
occupancy is calculated to be ca. 501km2 (Criteria VU B2<2,000 km2),
currently known to exist in 5–6 locations (Criteria VU B2a≤10); the area
of occupancy is rapidly decreasing due to slash-and-burn cultivation (Criteria
VU B2b(ii)). According to IUCN Red List Categories and Criteria (IUCN 2001), it meets
the criteria for Vulnerable (VU), but due to rescue possibilities from
surrounding regions, it is downgraded by one step to Near Threatened (NT).
Ophiorrhiza hispida Hook.f.,
Fl. Brit. India 3: 83. 1880; Kanjilal et al., Fl. Assam
3: 42. 1939; Deb & Mondalin Bull. Bot. Surv. India
39: 59. 1997.
Procumbent
hispid herb, ca. 35cm high.Leaves ovate-lanceolate, 7.5–14.5 ×
3–4.5 cm; lateral nerves 6–12 on either side; petiole 0.5–1.8
cm long. Stipules oblong-lanceolate,
acuminate. Inflorescence terminal capitatecymes, 1–2 cm across, subglobose.Flowers greenish-white or reddish, bracteate, epigynous, pedicellate,
5–6.5 cm long. Calyx obovoid;lobes 5, ca. 1 × 0.5 mm, ovate-lanceolate,
acute. Corolla 0.4–0.5 cm long, shortly funnel shaped, hispid outside,
villous at throat within; lobes 5, ca. 1.5 × 0.8 mm, ovate-oblong,
spreading, acute. Stamens 5, adnateto throat of corolla; anthers 1–1.25 mm long, linear-oblong; filaments
ca. 1 mm long, glabrous. Ovary obovoid to subglobose; styles
1–1.5 mm long, glabrous; stigma 2-lobed. Capsule ovate-oblong,
hispid, 2-locular; seeds brownish, 5–7 angular, glabrous.
Flowering & Fruiting: August–December.
Distribution: India [Assam (Cachar, Digboi), Meghalaya]; China.
Specimens examined: 73429 (Assam),
19.xi.1978, Assam, Cachar, Lailapur,Aizwal Road, coll. R.B. Majumdar;
73057 (Assam), 08.xi.1978, Bhuban Hill, coll. R.B. Majumdar.
Global Red List Category: Endangered (Walter & Gillett, 1998).
Regional Red List Category and Criteria: The Extent of occurrence is estimated to be
ca. 417km2 (Criteria EN B1<5,000km2); area of
occupancy estimated to be ca. 82.5km2 (Criteria B2<500 km2),
currently known to exist in three locations (Criteria EN B2a≤5); there is a
continuous decline in area, extent and quality of habitat due to encroachment
of forest land (Criteria EN B2b(iii)). Following the IUCN Red List Categories
and Criteria (IUCN 2001), this species has been classified as Endangered
(EN). As
there is no possibilities of rescue from neighboring
regions, hence there is no change to the initial assessment.
Ophiorrhiza repens (Wall.
ex G. Don) Bennet in Indian Forester 108: 302. 1982; Deb & Mondal in Bull.Bot. Surv. India 39: 99.1997. Ophiorrhiza calcarataHook. f., Fl. Brit. India 3: 84 1880. Mussaenda repensWall. ex G. Don, Gen. Hist. 3: 491. 1834.
Perennial herb. Stem
slender, erect, 25–50 cm high. Leaves elliptic-lanceolate,
3–12 × 1.5–4 cm long, lurid green above, pale beneath,
acuminate, glabrous above;petiole 1–1.5 cm long. Stipules lanceolate, entire or 2-fid. Cymes
8–20-flowered; branches short ascending; bracteoles much shorter than
flowers, linear pubescent. Calyx 2–3 × 1–1.5 mm,
pubescent; lobes 5, 1–1.25 × 0.5 mm,
ovate-lanceolate, acute, pubescent. Corolla white, 2–2.5 cm, tube
narrow, puberulous or tomentose,
throat hardly dilated; lobes 5, erect, 0.75–1 × 0.5 mm, ovate,
acute, much shorter than their recurved hispid dorsal
spur, glabrous within. Stamens
inserted at the middle of corolla; filaments 0.75–1.25 mm long; anthers ca.
2.5 mm long, linear-oblong. Ovary 1–1.5 × 0.75–1.25 mm, obovoid;
style 10–22 mm long; stigma-lobed, ca. 1.5 mm long; lobes elliptic-lanceolate, glabrous. Capsule
2–3.5 × 2–8.5 mm, pubescent.
Flowering & Fruiting: September–March.
Distribution: India [Assam (Cachar),
Arunachal Pradesh, Meghalaya, Mizoram, West Bengal]; Bhutan; Myanmar.
Specimens examined: 73181 (ASSAM), 10.ix.1978, Assam, Cachar, Amraghat, coll. R.B. Majumdar; 914 (ASSAM), 03.vi.2012, BhubanHill, coll. H.A. Barbhuiya.
Global Red List Category: Not Evaluated
Regional Red List Category and Criteria: The area of occupancy is estimated to be ca. 503km2 (Criteria VU B2<2,000 km2), currently known
to exist in six locations (Criteria VU B2b≤10); there is a continuous decline
in area, extent and quality of habitat due to encroachment of forest land
(Criteria VU B2b(iii)). According to IUCN Red List Categories
and Criteria (IUCN 2001), it meets the criteria for Vulnerable (VU), but due to
rescue possibilities from adjacent regions, it is downgraded by one step to
Near Threatened (NT) regionally.
Psychotria silhetensis Hook. f., Fl. Brit. India
3: 174. 1880; Deb & M. Gangop. in J. Econ. Taxon. Bot., Addit. Ser. 7: 144. 1989. Uragoga silhetensis(Hook. f.) Kuntze, Revis.
Gen. Pl. 2: 962. 1891.
subsp. silhetensis(Image 2(H).
Shrub ca. 1m high; branches glabrous. Leaves oblong-elliptic, 13–24 ×
6–9 cm, acuminate or acute at apex, cuneate at
base, glabrous; lateral nerves 13–20 on either
side, subparallel; petiole 1–1.5 cm long, glabrous. Stipules ovate-oblong, 1–2.5 ×
0.5–1 cm, acuminate at apex, glabrous. Inflorescence terminal or axillary
cymes, 2–4 × 2–2.5 cm, fruiting branches spreading, deflexed;
peduncles 3–4 cm long, thick, glabrous;
bracteoles minute, deltoid. Flowers greenish brown or white, pedicellate, 3–5 mm long, short tubular; pedicels
0.5–1 mm long, puberulous. Calyx 1.5–2
× 2–2.5 mm, cupular, puberulousabove; lobes 5, ovate-lanceolate,
acute at apex. Corolla tube 1.5–3 mm long, glabrousabove, densely velutinous at throat within; lobes 5,
1–2 mm long, ovate-lanceolate. Stamens 5,
inserted; filaments 0.5–0.7 mm long; anthers lanceolate,
0.5–0.8 mm long. Ovary ca. 0.5 mm; style 0.5–0.7
mm long; stigma 2-lobed. Fruits stalked, 8–13 × 5–6
mm, deep reddish when ripe.
Flowering & Fruiting: June-January.
Distribution: India [Assam (Cachar, Hailakandi, Mikir Hills-Kaliani, Kamrup-Bamunigaon),
Meghalaya, Mizoram, Arunachal Pradesh]; Bangladesh.
Specimen examined: 855 (ASSAM), 06.i.2012, Assam, Cachar, Inner Line Reserve Forest, Near Loharbond,
coll. H.A. Barbhuiya
Global Red List Category: Not Evaluated
Regional Red List Category and Criteria: Area of occupancy
estimated to be ca. 501km2 (Criteria VU B2<2,000km2),
currently known to exist in 6 locations (Criteria VU B2a≤10); the quality of
habitat is rapidly decreasing due to slash-and-burn cultivation and
encroachment of forest land (Criteria VU B2b(iii)).
Following the IUCN Red List Categories and Criteria (IUCN 2001), this species
has been classified as Vulnerable (VU). As there is no
possibilities of rescue from neighboring regions, hence there is no
change to the initial assessment.
Tarenna campaniflora (Hook.f.) N.P. Balakr. in Bull. Bot. Surv. India 22: 175. 1980. Webera campaniflora Hook.f., Fl.Brit. India 3: 106. 1880; Kanjilal et al., Fl. Assam3: 53. 1939. Ixora campaniflora (Hook.f.) Kuntze, Revis. Gen. Pl. 1: 278. 1891. Stylocoryna campaniflora(Hook.f.) K. Schum., Nat. Pflanzenfam.
4(4): 108. 1891. Image 2(I).
Shrub
or small tree. Leaves elliptic or
elliptic-lanceolate, 7.6–14 ×
2.5–5.8 cm, entire, shortly acuminate, acute at base or occasionally
rounded; glabrous above, pubescent or puberulous beneath; lateral nerves 12–15 on either
side; petiole 0.7–1.8 cm long. Stipules deciduous. Flower in terminal corymbose cymes; bracteoles two on each pedicel. Calyx hirsute; lobes
5, ovate-lanceolate, longer than the ovary. Corolla 1.5–2 cm long with a short
villous tube, spreading into a large campanulatelimb, 1.2–1.6 cm in dia.; lobes 5, short ovate, acute, glabrous. Stamens 5, fixed on the throat of the corolla; anthers long
sessile. Ovary 2-celled, one ovule in each cell; style short, hairy;
stigma long, fusiform. Fruit globose, 6–8 mm in diam.
Flowering & Fruiting: August–December.
Distribution: India [Assam (Cachar, N.C.
Hill-Haflong, Karbi Anglong-Dipu R.F., Bokajan, Sibsagar)]; Bangladesh; Myanmar.
Specimen examined: 4724 (Assam),
18.xi.1914, Assam, Cachar, Phulertal,
coll. U.N. Kanjilal; 112233 (Assam), 17.viii.2013, Lower Jiri Reserve Forest, coll. H.A. Barbhuiya.
Global Red List Category: Not Evaluated
Regional Red List Category and Criteria: The Extent of occurrence is estimated to be
ca. 101km2 (Criteria EN B1<5,000km2); Currently known from about three locations (Criteria
ENB2a<5). The area of occupancy is estimated to be ca. 60km2(Criteria EN B2<500 km2); there is a continuous decline in area,
extent and quality of habitat due to encroachment of forest land (Criteria EN B2b(iii)). Following IUCN Red List Categories and Criteria (IUCN 2001), it has been
categorized as Endangered (EN). As
there is no possibilities of rescue from neighboring
regions, hence there is no change to the initial assessment.
Conclusions
The Rubiaceae members are ecologically sensitive and in
combination with other factors such as restricted distribution, they are
vulnerable to extinction (Davis et al. 2009). With the increase in human population,
expansion of agricultural ac-tivities,
over-exploitation of forests for firewood, shifting cultivation, extensive
timbering, construction of roads and other developmental activities, the forest
cover of the region is rapidly shrinking and as a result the threatened taxa of
the region become more endangered. At present southern Assam has 116 tea gardens covering 8.14% of the
total geographical area of the region. Tropical rainforests were massively destroyed for the establishment of
tea gardens from 1858–1937. It is obvious that herbaceous plants discovered prior or during that
period had nearly disappeared, particularly those whichhad a limited population or were too restricted in distribution.
The present study
has allowed us to identify 14 threatened taxa, of which two are already extinct
from the region while the remaining are to be conserved as top priority. Efforts should be made to protect and
preserve the particular localities and habitats of these plants. The germplasmof all the surviving threatened taxa should be conserved in botanic gardens as
ex situ conservation. It is
suggested that these plants be multiplied through tissue culture techniques and
reintroduce the propagated clones to their natural habitats.
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