''Nicobariodendron'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

in the family

Celastraceae The Celastraceae (staff-vine or bittersweet) are a family of 97 genera and 1,350 species of herbs, vines, shrubs and small trees, belonging to the order Celastrales. The great majority of the genera are tropical, with only ''Celastrus'' (the staf ...

, with only one species, ''Nicobariodendron sleumeri'', a tree with simple, alternately set, entire leaves, small flowers and single seed fleshy fruits. It is only known from the

Nicobar Islands The Nicobar Islands are an archipelagic island chain in the eastern Indian Ocean. They are located in Southeast Asia, northwest of Aceh on Sumatra, and separated from Thailand to the east by the Andaman Sea. Located southeast of the Indian s ...

of India.

Description

''Nicobariodendron sleumeri'' is a

dioecious Dioecy (; ; adj. dioecious , ) is a characteristic of a species, meaning that it has distinct individual organisms (unisexual) that produce male or female gametes, either directly (in animals) or indirectly (in seed plants). Dioecious reproductio ...

evergreen tree of 8–35 m high, with simple, alternately set leaves without

stipule In botany, a stipule is an outgrowth typically borne on both sides (sometimes on just one side) of the base of a leafstalk (the petiole). Stipules are considered part of the anatomy of the leaf of a typical flowering plant, although in many speci ...

s. A leaf consists of a

leaf stalk In botany, the petiole () is the stalk that attaches the leaf blade to the stem, and is able to twist the leaf to face the sun. This gives a characteristic foliage arrangement to the plant. Outgrowths appearing on each side of the petiole in so ...

of 3–8 mm long, and an oblong oval to oblong inverted egg-shaped, leathery, hairless and shiny green

leaf blade A leaf (plural, : leaves) is any of the principal appendages of a vascular plant plant stem, stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", wh ...

of 5½-10 × 2–4 cm, with a foot that gradually narrows into the leaf stalk, an entire margin, and a blunt end that abruptly changes in a pointed tip of ½-1¼ cm. The leaf is pinnately veined with five to nine pairs of secondary veins. Male flowers sit in

spikes The SPIKES protocol is a method used in clinical medicine to break bad news to patients and families. As receiving bad news can cause distress and anxiety, clinicians need to deliver the news carefully. By using the SPIKES method for introducing a ...

in the

axils A leaf ( : leaves) is any of the principal appendages of a vascular plant stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, st ...

of the leaves. These flowers are said to be fragrant, white, small, about 2 mm in diameter, and tetra- or pentamerous, the petals are yellowish. They contain only two free

stamen The stamen (plural ''stamina'' or ''stamens'') is the pollen-producing reproductive organ of a flower. Collectively the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the filame ...

s, lying side-by-side, consisting of a filament of 1½-2½ mm long topped with an orbicular

anther The stamen (plural ''stamina'' or ''stamens'') is the pollen-producing reproductive organ of a flower. Collectively the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the filam ...

of ½-¾ mm, borne outside the disc and a short sterile pistil in the middle. Female flowers are mostly in

cymes An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Morphologically, it is the modified part of the shoot of seed plants where flowers are formed on ...

at the end of the branches. The conical fruit is a light red

drupe In botany, a drupe (or stone fruit) is an indehiscent fruit in which an outer fleshy part (exocarp, or skin, and mesocarp, or flesh) surrounds a single shell (the ''pit'', ''stone'', or '' pyrena'') of hardened endocarp with a seed (''kernel'') ...

of about 2 cm, with the calyx still present at its base, and it contains a single basal seed.

Taxonomy

''Nicobariodendron sleumeri'' was only described in 1986 (in a publication dated 1985), based on two herbarium specimens collected in 1974 and 1979 respectively, and the notes of the collectors. The describing authors assigned it to the Celastraceae, but the species is aberrant and other scholars have been hesitant to group it with other taxa, particularly because it had not been included in genetic analysis. In the

APG IV system The APG IV system of flowering plant classification is the fourth version of a modern, mostly molecular-based, system of plant taxonomy for flowering plants (angiosperms) being developed by the Angiosperm Phylogeny Group (APG). It was publishe ...

, it is placed in Celastraceae.

Etymology

The genus name is a combination of "Nicobar", a reference to the Nicobar Islands where the plants were found and "dendron", which is Latin for tree. The species name honors

Hermann Otto Sleumer Hermann Otto Sleumer (February 21, 1906 in Saarbrücken – October 1, 1993 in Oegstgeest) was a Dutch botanist of German birth. The plant genera ''Sleumerodendron'' Virot (Proteaceae) and ''Sleumeria'' Utteridge, Nagam. & Teo (Icacinaceae The I ...

, a twentieth century Dutch botanist of German birth.

Distribution

''Nicobariodendron sleumeri'' is an

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

Great Nicobar Island Great Nicobar is the southernmost and largest of the Nicobar Islands of India, north of Sumatra. History The Nicobar Island has been well known to Indian mariners since the time of the seafaring Cholas https://www.britannica.com/place/Nicoba ...

and

Katchal Island Katchal (Hindi: कत्चल, Nicobarese: तिहन्यु, ''Tihnyu'') is one of the Nicobar Islands, India. History Katchal Island was previously known as Tihanyu. Due to the remote location and lack of exposure with the rest of the ...

. Only the two

type specimen In biology, a type is a particular wiktionary:en:specimen, specimen (or in some cases a group of specimens) of an organism to which the scientific name of that organism is formally attached. In other words, a type is an example that serves to a ...

are known, a flowering male tree from Great Nicobal and a fruiting female tree from Katchal. Female inflorescences are described but were not part of the herbarium specimen.

References

{{Taxonbar, from1=Q14245023, from2=Q1986042 Celastraceae Celastrales genera Monotypic rosid genera Dioecious plants