''Nepenthes abgracilis'' is a tropical

pitcher plant Pitcher plants are several different carnivorous plants which have modified leaves known as pitfall traps—a prey-trapping mechanism featuring a deep cavity filled with digestive liquid. The traps of what are considered to be "true" pitcher p ...

native to the

Philippines The Philippines (; fil, Pilipinas, links=no), officially the Republic of the Philippines ( fil, Republika ng Pilipinas, links=no), * bik, Republika kan Filipinas * ceb, Republika sa Pilipinas * cbk, República de Filipinas * hil, Republ ...

. It is known only from northeastern

Mindanao Mindanao ( ) ( Jawi: مينداناو) is the second-largest island in the Philippines, after Luzon, and seventh-most populous island in the world. Located in the southern region of the archipelago, the island is part of an island group of ...

, including Mount Legaspi. Little is known about the altitudinal distribution of this species, but the

holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of sever ...

was collected at 670 m. This species belongs to the informal " ''N. micramphora'' group", which also includes '' N. cid'' from north-central Mindanao and '' N. micramphora'' from southeastern Mindanao. The specific epithet '' ab gracilis'' means "from gracilis" and refers to

Elmer Drew Merrill Elmer Drew Merrill (October 15, 1876 – February 25, 1956) was an American botanist and taxonomist. He spent more than twenty years in the Philippines where he became a recognized authority on the flora of the Asia-Pacific region. Through t ...

's early identification of a herbarium specimen of this species as '' N. gracilis''.

Botanical history

Field observations

Habitat photographs of a

taxon In biology, a taxon ( back-formation from '' taxonomy''; plural taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular n ...

matching the description of ''N. abgracilis'' appeared in a 2008 issue of the German-language periodical, ''

Das Taublatt ''Das Taublatt'' is a triannual German-language periodical based in Bochum and the official publication of Gesellschaft für fleischfressende Pflanzen im deutschsprachigen Raum, a carnivorous plant society based in Germany.Rice, B. 2010Carnivor ...

'', and in the second volume of Stewart McPherson's 2009 work, ''

Pitcher Plants of the Old World ''Pitcher Plants of the Old World'' is a two-volume monograph by Stewart McPherson on the pitcher plants of the genera '' Nepenthes'' and ''Cephalotus''. It was published in May 2009 by Redfern Natural History Productions and covers all species ...

''.McPherson, S.R. 2009. ''

''. 2 volumes. Redfern Natural History Productions, Poole. In both it was identified as a variant of '' N. alata'' (at the time considered a highly variable and widespread species, but which has since been split into a number of daughter taxa).

Formal description

''Nepenthes abgracilis'' was formally described by botanists

Martin Cheek Martin Roy Cheek (born 1960) is a botanist and taxonomist at the Royal Botanic Gardens, Kew.Matthew Jebb Matthew Hilary Peter Jebb (born 1958) is an Irish botanist and taxonomist specialising in the ant plant genera ''Squamellaria'', '' Myrmecodia'', '' Hydnophytum'', ''Myrmephytum'' and '' Anthorrhiza'', as well as the carnivorous plant genus '' ...

in the e-published 6 December 2013 issue of ''

Phytotaxa ''Phytotaxa'' is a peer-reviewed scientific journal for rapid publication on any aspect of systematic botany. It publishes on a wide range of subjects, but focuses on new species, monographs, floras, revisions, reviews, and typification issues ...

''. In the same paper Cheek and Jebb introduced the " ''N. micramphora'' group", to which ''N. abgracilis'' was assigned, and described a third member of this group, '' N. cid''. ''Nepenthes abgracilis'' was one of 12 new ''Nepenthes'' species described by Cheek and Jebb in 2013.Smith, L. 2014
Pitcher perfect - but carnivorous plants are at risk
''The Independent'', 5 January 2014. The herbarium specimen ''Ramos & Pascasio in BS 34501B'' is the designated

and is deposited at the herbarium of the

University of California The University of California (UC) is a public land-grant research university system in the U.S. state of California. The system is composed of the campuses at Berkeley, Davis, Irvine, Los Angeles, Merced, Riverside, San Diego, San Franci ...

(UC) in

Berkeley Berkeley most often refers to: *Berkeley, California, a city in the United States **University of California, Berkeley, a public university in Berkeley, California * George Berkeley (1685–1753), Anglo-Irish philosopher Berkeley may also refer ...

California California is a state in the Western United States, located along the Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the most populous U.S. state and the 3rd largest by area. It is also the m ...

. A photographic record of this specimen is held at the

Royal Botanic Gardens, Kew Royal Botanic Gardens, Kew is a non-departmental public body in the United Kingdom sponsored by the Department for Environment, Food and Rural Affairs. An internationally important botanical research and education institution, it employs 1,10 ...

(K) in

London London is the capital and List of urban areas in the United Kingdom, largest city of England and the United Kingdom, with a population of just under 9 million. It stands on the River Thames in south-east England at the head of a estuary dow ...

England England is a country that is part of the United Kingdom. It shares land borders with Wales to its west and Scotland to its north. The Irish Sea lies northwest and the Celtic Sea to the southwest. It is separated from continental Europe b ...

. The holotype was collected in April 1919 in the former Surigao Province of

island, the

. The type locality is not specified further, although the altitude is recorded as 670 m above sea level.''Nepenthes abgracilis'' Jebb & Cheek

International Plant Names Index The International Plant Names Index (IPNI) describes itself as "a database of the names and associated basic bibliographical details of seed plants, ferns and lycophytes." Coverage of plant names is best at the rank of species and genus. It inclu ...

(IPNI).

Description

''Nepenthes abgracilis'' is a

climbing plant A vine (Latin ''vīnea'' "grapevine", "vineyard", from ''vīnum'' "wine") is any plant with a growth habit of trailing or scandent (that is, climbing) stems, lianas or runners. The word ''vine'' can also refer to such stems or runners themselv ...

growing to a height of several metres. Rosette and short stems are not represented among the studied herbarium material and are therefore unknown. Climbing stems are

terete Terete is a term in botany used to describe a cross section that is circular, or like a distorted circle, with a single surface wrapping around it.Lichen Vocabulary, Lichens of North America Information, Sylvia and Stephen Sharnoff/ref> This is u ...

, wingless, and 6–7 mm in diameter, with

internodes A stem is one of two main structural axes of a vascular plant, the other being the root. It supports leaves, flowers and fruits, transports water and dissolved substances between the roots and the shoots in the xylem and phloem, stores nutrien ...

15–18 mm long. The stem has a "moderately dense" covering of

sessile Sessility, or sessile, may refer to: * Sessility (motility), organisms which are not able to move about * Sessility (botany), flowers or leaves that grow directly from the stem or peduncle of a plant * Sessility (medicine), tumors and polyps that ...

, depressed-

globose A sphere () is a geometrical object that is a three-dimensional analogue to a two-dimensional circle. A sphere is the set of points that are all at the same distance from a given point in three-dimensional space.. That given point is the ...

, red glands measuring 0.05 mm in diameter.

Leaves

The spirally-arranged leaves are

coriaceous This glossary of botanical terms is a list of definitions of terms and concepts relevant to botany and plants in general. Terms of plant morphology are included here as well as at the more specific Glossary of plant morphology and Glossary o ...

(leathery) in texture and lack a defined petiole. The laminae (leaf blades) are narrowly

oblanceolate The following is a list of terms which are used to describe leaf morphology in the description and taxonomy of plants. Leaves may be simple (a single leaf blade or lamina) or compound (with several leaflets). The edge of the leaf may be regular ...

-oblong and measure up to 29 by 3.1 cm. The laminar apex is

attenuate In physics, attenuation (in some contexts, extinction) is the gradual loss of flux intensity through a medium. For instance, dark glasses attenuate sunlight, lead attenuates X-rays, and water and air attenuate both light and sound at vari ...

. The leaf base gradually narrows towards the stem, where it is around 1.3 cm wide. It clasps the stem for three-quarters to four-fifths of its circumference, having an angled insertion and forming wings 0.3–0.4 cm wide. These wings are shortly

decurrent ''Decurrent'' (sometimes decurring) is a term used in botany and mycology to describe plant or fungal parts that extend downward. In botany, the term is most often applied to leaf blades that partly wrap or have wings around the stem or petio ...

, terminating 0.9–1.2 cm below the

leaf axil 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, ste ...

. Three to four longitudinal veins are present on either side of the

midrib This glossary of botanical terms is a list of definitions of terms and concepts relevant to botany and plants in general. Terms of plant morphology are included here as well as at the more specific Glossary of plant morphology and Glossary o ...

. These originate from the leaf base and along the midrib, and run through the outer three-quarters of the leaf blade. They are visible only on the

adaxial {{Short pages monitor bears around 20 narrowly elliptic-oblong glands, each measuring roughly 0.75 by 0.25 mm. The lid–peristome junction has deeply sunken, unbordered glands around 0.25 mm in diameter. Sessile glands similar to those found on the stem are distributed only near the lid margin, though they are few and inconspicuous. An

entire Entire may refer to: * Entire function, a function that is holomorphic on the whole complex plane * Entire (animal), an indication that an animal is not neutered * Entire (botany) This glossary of botanical terms is a list of definitions of ...

(unbranched)

spur A spur is a metal tool designed to be worn in pairs on the heels of riding boots for the purpose of directing a horse or other animal to move forward or laterally while riding. It is usually used to refine the riding aids (commands) and to ba ...

is inserted near the base of the lid.

Inflorescence

The available herbarium specimens do not include any floral material and therefore the morphology of the

inflorescence An inflorescence is a group or cluster of flowers arranged on a Plant stem, stem that is composed of a main branch or a complicated arrangement of branches. Morphology (biology), Morphologically, it is the modified part of the shoot of sperma ...

and

infructescence Infructescence (fruiting head) is defined as the ensemble of fruits derived from the ovaries of an inflorescence. It usually retains the size and structure of the inflorescence. In some cases, infructescences are similar in appearance to simple fru ...

is not known.

Indumentum

The stem, as far as is known, is

glabrous Glabrousness (from the Latin '' glaber'' meaning "bald", "hairless", "shaved", "smooth") is the technical term for a lack of hair, down, setae, trichomes or other such covering. A glabrous surface may be a natural characteristic of all or part of ...

(hairless), though the stem apex has not been documented. The laminae are likewise glabrous. The upper pitchers are completely devoid of an

indumentum In biology, an indumentum (Latin, literally: "garment") is a covering of trichomes (fine "hairs") on a plant Davis, Peter Hadland and Heywood, Vernon Hilton (1963) ''Principles of angiosperm taxonomy'' Van Nostrandpage, Princeton, New Jersey, pa ...

apart from a small number of inconspicuous, simple hairs (0.05–0.10 mm long) near the peristome.

Colouration

The upper surface of the lamina is dark green; the lower surface dries brown, as seen in herbarium material. Upper pitchers have a yellowish-green exterior and a red peristome. The underside of the lid is either flushed with red or red speckled.

Distribution and habitat

''Nepenthes abgracilis'' is known with certainty only from the former Surigao Province on the island of

in the

(an area that is now divided between the provinces of Surigao del Norte and

Surigao del Sur Surigao del Sur ( Surigaonon: ''Probinsya nan Surigao del Sur''; ceb, Habagatang Surigao; tl, Timog Surigao), officially the Province of Surigao del Sur, is a province in the Philippines located in the Caraga region in Mindanao. Its capital is T ...

), where the

type specimen In biology, a type is a particular 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 anchor or centralizes th ...

was collected. It is said to grow on "forested submontane ridges", likely over

ultramafic Ultramafic rocks (also referred to as ultrabasic rocks, although the terms are not wholly equivalent) are igneous and meta-igneous rocks with a very low silica content (less than 45%), generally >18% MgO, high FeO, low potassium, and are composed ...

substrates, at 670 m above sea level. It also apparently occurs on Mount Legaspi, where it has been photographed ''in situ''. Further research may show it to be more widespread in the region. The species grows terrestrially. Since it is only known from a single locality, Cheek and Jebb informally assessed the

conservation status The conservation status of a group of organisms (for instance, a species) indicates whether the group still exists and how likely the group is to become extinct in the near future. Many factors are taken into account when assessing conservatio ...

of ''N. abgracilis'' as Critically Endangered based on the IUCN criteria. The authors noted that while there is mining activity for metal ore on Mount Legaspi, this is currently at lower elevations than the 670 m at which the species was collected.

Related species

''Nepenthes abgracilis'' is a member of the informal " ''N. micramphora'' group", which also includes '' N. cid'' from north-central Mindanao and '' N. micramphora'' from southeastern Mindanao. ''Nepenthes abgracilis'' is most easily distinguished from ''N. micramphora'' by its upper pitchers, which are subcylindric (versus more-or-less

infundibular An infundibulum (Latin for ''funnel''; plural, ''infundibula'') is a funnel-shaped cavity or organ. Anatomy * Brain: the pituitary stalk, also known as the ''infundibulum'' and ''infundibular stalk'', is the connection between the hypothalamus and ...

in ''N. micramphora''), widest near the base (versus narrowest at the base and widest in the middle or upper half), and much larger in all respects ( 16 cm versus ≤6.7 cm high). Another distinguishing feature is the

, which is

in ''N. abgracilis'' and branched in ''N. micramphora''. ''Nepenthes cid'' differs from both ''N. abgracilis'' and ''N. micramphora'' in growth habit (it is

epiphytic An epiphyte is an organism that grows on the surface of a plant and derives its moisture and nutrients from the air, rain, water (in marine environments) or from debris accumulating around it. The plants on which epiphytes grow are called phoroph ...

as opposed to terrestrial),

development (vegetative parts hairy as opposed to subglabrous), and in having a distinct petiole (versus

in the other two).

References

{{Taxonbar, from=Q15304868 Carnivorous plants of Asia abgracilis Plants described in 2013 Taxa named by Martin Cheek Taxa named by Matthew Jebb