647. RONDELETIA BUXIFOLIA - Royal Botanic Gardens, Kew

647. RONDELETIA BUXIFOLIA 

Rubiaceae 

Plant in Peril, 32 

Colin Clubbe, Martin Hamilton and Marcella Corcoran 

Summary. Rondeletia buxifolia Vahl (Rubiaceae) a critically endangered shrub, 

restricted to the Caribbean Island of Montserrat, is described and illustrated. 

Its distribution and conservation status are reviewed. 

Rondeletia buxifolia Vahl is a small multi-stemmed shrub, restricted 

to the Caribbean island of Montserrat, a UK Overseas Territory 

(UKOT). The earliest botanical collections in Montserrat were made 

by John Ryan in the late 18th century. He lived and worked on the 

island for many years as a physician and a plantation owner. During 

this time, Ryan sent many herbarium specimens to the Copenhagen 

Herbarium in his home country of Denmark. These included the type 

specimens of R. buxifolia and another Montserrat endemic, the small 

tree Xylosma serrata Urb. (Salicaceae). Based on Ryan’s collections, 

M. H. Vahl published R. buxifolia as a new species in 1798. 

Rondeletia L. is a neotropical genus of small trees and shrubs in 

the family Rubiaceae. A few species, such as Rondeletia odorata Jacq. 

and Rondeletia amoena Hemsl. have been brought into cultivation for 

their colourful flowers and their scented inflorescence. Two hundred 

and sixty-four species of Rondeletia have been described and 

are distributed from Mexico to Tropical America and across the 

Caribbean (Govaerts et al., 2008). One hundred and thirty species 

have a Caribbean distribution with a centre of diversity in Cuba 

where 65 species are endemic. Of the Caribbean species, 135 are single 

island endemics and the smaller islands of Montserrat, Anguilla, 

St Vincent and Martinique each support a single species. Seventeen 

species of Rondeletia are listed on the global red list of threatened 

species (IUCN, 2008). 

From the late 18th century, Montserrat was little visited by botanists 

and there are relatively few records of Rondeletia buxifolia, most notably 

by J.S. Beard in 1944, and by G.R. Proctor in 1959. Richard Howard 

produced the first extensive checklist of the flora of Montserrat for his 

Flora of the Lesser Antilles (Howard, 1974–1989). This remains the most 

Curtis’s Botanical Magazine 2009 vol. 26 (1&2): pp. 131–141 

© The Board of Trustees of the Royal Botanic Gardens, Kew 2009. 131

important and comprehensive botanical inventory of Montserrat 

and the other islands in the Lesser Antilles. Howard’s collections 

of R. buxifolia in 1979 represent the last known herbarium specimen 

vouchers of this species collected before the current Kew programme 

in Montserrat. 

In 1995, the Soufrière Hills volcano in the south of the island 

rumbled to life for the first time in more than 400 years. For two 

years it released gas and ash and there was increased seismic activity 

and lava dome growth. A major set of explosions in 1997 and 

dome collapse unleashed a series of pyroclastic flows that buried 

the capital city of Plymouth and many surrounding villages. Among 

the losses were the island’s agriculture station and botanic garden 

together with large areas of natural forest. Today, nearly half the 

island is an exclusion zone and life is re-establishing itself in the north 

creating inevitable pressure on the remaining forested areas and their 

constituent plant and animal species. 

In 2005 the UK government’s Darwin Initiative funded a collaborative 

project to undertake a biodiversity assessment of Montserrat’s 

Centre Hills and to develop a management plan to help guide 

future conservation activities (www.malhe.gov.ms/centrehills/). This 

project enabled Kew’s UK Overseas Territories Programme to work 

with the Montserrat government and the Montserrat National Trust 

to undertake the first comprehensive botanical assessment of the 

Centre Hills, and the first major piece of botanical fieldwork in 

Montserrat since Howard’s pioneering work in the seventies. Over 

the last three years a series of botanical expeditions has resulted in 

a good understanding of the plants of Montserrat, their key habitats 

and how the volcanic eruptions have impacted on them. This has 

enabled the production of a new vegetation map for Montserrat, a 

species checklist and candidate red list, with a clearer understanding 

of the distribution of Montserrat’s most important species for conservation, 

including Rondeletia buxifolia (Hamilton et al., 2008). The first 

steps were also taken in indentifying the key threats these species face 

and the conservation action required for their long-term survival. 

Much of Montserrat’s 63 km 2 is very rugged comprising three 

distinct volcanic ranges: the oldest geologically is the Silver Hills (to 

450 m) in the north, the Centre Hills (to 740 m) and the youngest 

and currently active volcanic region of the Soufrière Hills (to 900 m) 

132 © The Board of Trustees of the Royal Botanic Gardens, Kew 2009.

Plate 647 Rondeletia buxifolia (large flowers and leaves × 5) christabel king

© The Board of Trustees of the Royal Botanic Gardens, Kew 2009. 135 

The northern flanks of the Centre Hills, dominated by Katy Hill (740m). The lower elevation forests in the foreground show typical habitat for Rondeletia 

buxifolia. Patches of encroaching agriculture are also evident. Photograph: Colin Clubbe.

in the south. The vegetation of Montserrat is largely determined by 

theamountofrainfall,whichisinturn closely linked to elevation. 

Secondary vegetation now covers most of the island due to historical 

clearance for agriculture, timber and charcoal. Hamilton et al. (2008) 

identified three major forest types for their vegetation map largely 

based on a broad moisture gradient and containing a characteristic 

set of species: Dry Forest types, Mesic Forest types and Wet Forest 

types. Two further habitats of much more restricted distribution and 

fewer characteristic species were also identified: Littoral Forest and 

Elfin Woodland. 

Inland, at lower altitudes and where rainfall is limited Rondeletia 

buxifolia grows in the dry scrub or thickets of the Silver Hills. It occurs 

in stands of Dry Forest (seasonally deciduous sub-tropical woodland) 

with low rainfall, usually along lower valleys and hill ridges and 

alongside seasonal stream beds. Mesic Forest begins to appear as 

more moisture becomes available, usually at moderate elevations and 

further up along stream beds and is a preferred habitat for R. buxifolia. 

(Hamilton et al., 2008). R. buxifolia does not occur in Wet Forest types. 

When growing in the shade and shelter of other species, R. buxifolia has 

an elongated and spindly habit, with soft lush green leaves; however, it 

will eventually fall over, reaching the ground and producing new roots 

on the stem thus creating a new plant. The opposite is true for the 

individuals growing in full sun, which produce a sturdy compact shrub 

with thicker stems and leaves able to withstand the harsh environment 

of sun and wind. Individuals growing in full sun flower earlier and 

much more profusely, with flowering declining as shade increases 

indicating a preference for forest edge habitats. An analysis by Jones 

(2008) showed sexual reproduction, as indicated by fruit presence, to 

be predominantly positively influenced by increasing light levels. 

A recent study has shown that Rondeletia buxifolia is more widespread 

within the Silver Hills than was originally realised and has provided 

a better understanding of its distribution outside the Centre Hills 

(Jones, 2008). Jones (2008) also calculated a total extent of occurrence 

(sensu IUCN, 2001) of R. buxifolia to be 16.6 km 2 .Theonlyforest 

area in Montserrat currently under legal protection is the Centre 

Hills Forest Reserve which comprises an area of approximately 1110 

ha occupying the central areas of the Centre Hills range above an 

elevation of approx 200 m. Although an important protected area 


Legend: 

Rondeletia buxifolia points 

Contours 

Forest Reserve boundary 

Volcanic deposits 

Scale: 1 cm = 1.4 Km 

Map of Montserrat, showing recorded locations of Rondeletia buxifolia. Drawn by M.A. Hamilton. 

for many Montserrat species and for watershed protection, ∼ 90% 

of the population of R. buxifolia is located outside the Forest Reserve 

and afforded no real protection. However, a new Conservation 

and Environmental Management Bill is being drafted which will 

offer species level protection to Montserrat’s key species, including 

R. buxifolia. The Bill is due to be enacted in 2009. 


There is great concern for the long-term survival of Rondeletia 

buxifolia, due to a decline in suitable habitat attributable to: 

• Volcanic eruptions which threaten the Dry and Mesic Forest 

habitats. Apart from pyroclastic flows which destroy everything 

in their path, volcanic ash and acid rain defoliate the vegetation, 

leading to a decline in the number of individuals. 

• Pressure from residential infrastructure and tourism development 

resulting in direct loss, degradation and fragmentation of 

suitable habitat. 

• Alien invasive plant species including Psidium guajava L. and 

Cryptostegia madagascariensis Bojer ex Decne. These species 

compete aggressively with native vegetation and are spreading 

rapidly, causing serious damage to habitats and species. A 

recent study used prediction mapping of the spread of these two 

species and showed a near complete overlap with the habitat 

requirements of R. buxifolia which could result in the virtual 

elimination of this species from Montserrat should the spread of 

these invasive species remain unchecked (Stow, 2008). 

• Pressure from feral livestock poses a major threat to the 

R. buxifolia, in particular the goats roaming in the Silver Hills, 

which chew plants to the ground, severely limiting regeneration. 

The effect that rats have on seedling regeneration is currently 

unknown, but is under investigation. 

• Climate change has the potential to change the climatic envelope 

of R. buxifolia with as yet unknown effects. 

Based on knowledge of the distribution of Rondeletia buxifolia and 

the threats that the species is facing Hamilton et al. (2008) suggested 

a candidate red list status of critically endangered. Data provided by 

Jones (2008) has confirmed this assessment and enabled R. buxifolia to 

be formally assessed as Critically Endangered B1ab(iii, v) based on 

the IUCN red list criteria (IUCN, 2001). 

Conservation Measures. An integrated conservation strategy is 

being developed for R. buxifolia involving both ex situ and in situ 

conservation measures, plus raising awareness about the status and 

importance of this species. The UK government’s Overseas Territories 

Environment Programme (OTEP) have recently funded a 


project to enable species action plans to be developed in a participatory 

way with local stakeholders in Montserrat for the most important 

species of plants, amphibians, reptiles and mammals. These follow 

the successfully completed action plant for the critically endangered 

Montserrat oriole (Hilton et al., 2005). The workshop to develop a 

species action plan for Montserrat’s endemic plants was held in 2008 

and a draft action plan is in circulation for comment. Recommended 

conservation actions build on those currently under way. 

In 2006 seed of Rondeletia buxifolia was collected for long-term 

seed banking at Kew’s Millennium Seed Bank (MSB). The seed was 

collected from within the Centre Hills Forest Reserve and sent to the 

MSB for banking. This collecting was undertaken as part of a broader 

conservation strategies training workshop to help build conservation 

capacity in Montserrat, and seeds of other critical species have been 

collected for the MSB since then. A portion of the seed lot of 

R. buxifolia was sent to Kew to be used to develop a horticulture 

protocol. The UKOT Programme is engaged in developing full 

horticulture protocols for UKOT’s threatened species, and training 

local counterparts is part of their core activity (Hamilton et al., 2007; 

Corcoran et al., 2008). This is also contributing directly to meeting 

the targets of the Global Strategy for Plant Conservation (GSPC, 

2002). The horticulture protocol has been completed and sent to the 

Montserrat National Trust (Corcoran et al., 2008). Kew has been 

helping the Montserrat National Trust to establish a new botanic 

garden at its headquarters in the north of the island in a project 

also funded by OTEP. The Trust’s original offices in Plymouth were 

destroyed by the 1997 volcanic eruptions as was the island’s original 

botanic garden. A new nursery has been completed and several of 

Montserrat’s threatened and culturally important plant species are 

in cultivation there. Observations on the growth form of R. buxifolia 

in the wild suggested that it would make a good hedging plant 

and a trial hedge has been planted out at the Montserrat Botanic 

Garden. Early indications from this trial are very positive and a 

plan is being developed to supply plants for the Montserrat general 

public to encourage wider use of this species in landscaping. This 

would have several benefits. An endemic species being used in a 

sustainable way would be a flagship for conservation awareness. It 

could replace non-native species of Ficus currently widely used for 


F 

E 

A 

C 

D 

B 

Rondeletia buxifolia. A, leaf (largest), × 1; B, growing point with buds and two leaves, × 2; C, 

node with buds, × 4; D, l.s. flower, × 4; E, style, × 8; F, t.s. ovary, × 10. Drawn by Christabel 

King from living material at Kew. 

hedging which has detrimental impacts on the soil and provide an 

unfriendly environment for local biodiversity. In the short-term the 

outlook for R. buxifolia is quite positive. Its future has been secured 

ex situ by long-term seed banking in the MSB, and by cultivation in 

Montserrat and at Kew. However, its future in situ remains precarious, 

as habitat is lost and individuals destroyed as the infrastructural 

demands of a re-establishing nation in the north of the island clash 

with the centre of diversity for this critically endangered species. 

Rondeletia buxifolia Vahl, Eclogae Americanae ii. 11, t. 12 (1798). Type: 

habitat in Montserrat. Ryan (C). 

Description. A lax or dense shrub 1–3 m tall, with slender arching 

branches. Stipules subannular, 1 mm long, strigillose. Leaf petioles 1–2 mm long; 

blades cuneate-obovate to spathulate, 1.3–3.5 × 0.7–1.7 cm, base cuneate, apex 

rounded or retuse, glabrous or appressed pubescent on the veins at the leaf base. 

Inflorescence axillary, 1- to 3-flowered, pedicels to 2 mm; calyx lobes 4, linear 

or oblanceolate, 1.5–3 mm long, acute; corolla salveri form, tube 6–7 mm, 

cream or buff to yellowish, retrorsely pubescent outside, lobes 4, 1.5–2 mm 

long. Capsules sub-globose, 4 mm in diameter, tomentulous; seeds 1mmlong, 

angulate, reticulate, winged (adapted from Howard, 1989 p.456). 


Distribution. Caribbean: restricted to Montserrat. 

Habitat. Restricted to an area of 16.6 km 2 in the north of the island in 

Dry Forest (seasonally deciduous sub-tropical woodland), Dry Scrub, and Mesic 

Forest at low elevations. 

Conservation status. Critically Endangered B1ab(iii, v). 

REFERENCES 

Corcoran, M.R., Robbins, S.K., Hamilton, M.A. & Clubbe, C. (2008). Report 

on the Status of Rondeletia buxifolia Vahl., Including a Germination and Cultivation 

Protocol. Internal Report, Royal Botanic Gardens, Kew. 

Govaerts, R., Ruhsam, M., Andersson, L., Robbrecht, E., Bridson, D., 

Davis, A., Schanzer, I. & Sonké, B. (2008). World Checklist of Rubiaceae. The 

Board of Trustees of the Royal Botanic Gardens, Kew. Published on the 

Internet; www.kew.org/wcsp/rubiaceae/. Downloaded on 10 November 

2008. 

GSPC (2002). Global Strategy for Plant Conservation.PublishedbytheSecretariatof 

the Convention on Biological Diversity. Available at: www.cbd.int/gspc/. 

Hamilton, M.A., Clubbe, C., Robbins, S.K. & Bárrios, S. (2008). Plants and 

habitats of the Centre Hills and Montserrat. In: Young, R.P. (ed.), A Biodiversity 

Assessment of the Centre Hills, Montserrat. Durrell Conservation Monographs, Vol.1, 

pp. 40–55. Downloadable from www.durrell.org/Conservation/Where-wework/Caribbean-Islands/. 

Hamilton, M.A., Robbins, S.K., Johnson, N.P., Sanchez, M.D. & Clubbe, C. 

(2007). Report on the status of Acacia anegadensis Britton Including a Germination 

and Cultivation Protocol. Unpublished Report, RBG Kew. Available at: 

www.kew.org/scihort/ukots/Pages/bvi2bi.htm. 

Hilton, G.M., Gray, G.A.L., Fergus, E., Sanders, S.M., Bloxam, Q., 

Clubbe, C. & Ivie, M. (eds.) (2005). Species Action Plan for the Montserrat oriole, 

Icterus oberi, 2005–2009. Department of Agriculture, Montserrat. 

Howard, R.A. (1974–1989). Flora of the Lesser Antilles: Leeward and Windward 

Islands. 6 volumes. Arnold Arboretum, Harvard University, Jamaica Plain, 

USA. 

Howard, R.A. (1989). Rondeletia buxifolia Vahl. Flora of the Lesser Antilles: Leeward 

and Windward Islands. vol. 6 Dicotyledoneae (Part. 3). Arnold Arboretum, 

Harvard University, Jamaica Plain, USA. p. 456–457. 

IUCN (2001). IUCN Red List Categories version 3.1. IUCN Species 

Survival Commission, IUCN. Gland and Cambridge. Available at: 

www.iucnredlist.org/static/categories_criteria. 

IUCN (2008). 2008 IUCN Red List of Threatened Species. www.iucnredlist.org. 

Downloaded on 10 November 2008. 

Jones, M. (2008). Distribution and Conservation of Montserrat’s Endemic Flora. 

Unpublished MSc thesis Imperial College, London. 

Stow, S. (2008). Non-Native Plant Distribution in Montserrat: Conservation and Ecological 

Aspects. Unpublished MSc thesis Imperial College, London.

647. RONDELETIA BUXIFOLIA - Royal Botanic Gardens, Kew

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