Hypericum sechmenii

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Hypericum sechmenii
Scientific classification OOjs UI icon edit-ltr.svg
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Clade: Rosids
Order: Malpighiales
Family: Hypericaceae
Genus: Hypericum
Section: Hypericum sect. Adenosepalum
Species:
H. sechmenii
Binomial name
Hypericum sechmenii
Ocak & O.Koyuncu
Turkey adm location map.svg
Red pog.svg
Red pog.svg
Approximate distribution of Hypericum sechmenii within Turkey [1]

Hypericum sechmenii, or Seçmen's St John's wort, is a rare species of flowering plant of the St John's wort family (Hypericaceae) that is found in the Eskişehir Province of central Turkey. It was first described in 2009 by Turkish botanists Atila Ocak and Onur Koyuncu, who named the species in honor of Özcan Seçmen, a fellow botanist. They assigned the species to the genus Hypericum , and Norman Robson later placed H. sechmenii into the section Adenosepalum .

Hypericum sechmenii is a perennial herb that usually grows in clusters of stems 3–6 centimeters (1–2 inches) tall and blooms in June and July. The stems of the plant are smooth and lack hairs, while the leaves are leathery and do not have leafstalks. Its flowers are arranged in clusters that form a flat-topped shape known as a corymb, and each flower possesses five bright yellow petals. There are several species that are similar in appearance to H. sechmenii, with only minor physical differences that set them apart. The most closely related of these are Hypericum huber-morathii , Hypericum minutum , and Hypericum thymopsis .

Found among limestone rocks, Hypericum sechmenii has an estimated distribution of less than 10 square kilometers (4 square miles), with fewer than 250 surviving plants. Despite containing druse crystals and toxic chemicals that are thought to deter herbivory, the species is threatened by overgrazing from livestock, as well as by other factors like climate change and habitat loss.

Description

Hypericum sechmenii is a flowering perennial herb that grows in dense clusters of upright stems typically 3–6 cm (1–2 in) tall, [2] sometimes up to 8 cm (3 in) tall. [3] It has five-petalled yellow flowers [4] that usually flower in June and July. [3]

Vegetative structures

The outside of its roots is made of a thick cuticle, a protective waterproof covering made of fats and wax. Directly beneath the cuticle are one to two bark-like layers of periderm that are composed of several layers of dead cells. Beneath the periderm are several layers of thin-walled cells called a cortex. The tissue of the roots is completely covered in a layer of the water transport tissue found in plants called xylem. [5]

The numerous smooth and hairless stems [3] of Hypericum sechmenii have multiple layers of different kinds of cells. On the outside is a thin cuticle that covers a single layer of epidermis. Beneath this epidermis, there are several layers of oblong peridermal cells. These contain a waxy substance called suberin that is hydrophobic. Some cells in the periderm of the stems also contain inorganic minerals known as druse crystals, [6] which a 2020 paper theorized might deter herbivory because of their toxicity. [7] Beneath the periderm is the main growth tissue, the vascular cambium, which produces xylem and the transport tissue found in plants called phloem. [6]

The leaves of Hypericum sechmenii lack leafstalks, instead attaching directly to the stems. They are roughly 0.2–0.5 cm (0.08–0.2 in) long, [2] [3] and densely overlap each other. The texture of the leaves is described as subcoriaceous, or somewhat leathery. The shape of the leaves is either egg-like (ovate) with a broader base, or elliptic with rounded tips and pointed bases (cuneate). There are numerous pale glands on the surfaces of the leaves, and a few black glands can be found on their edges. [3] The black glands are large enough to be seen by the naked eye, but to see the pale glands the leaf may need to be held up to a light. In the type species of the genus, H. perforatum , the pale glands contain and excrete essential oils, while the black glands contain red-staining phenolic compounds (anthraquinone derivatives) that deter some herbivorous insects. [8] On the top and bottom sides of the leaves there are pores (stomata) that regulate gas exchange, and there is tightly packed photosynthetic tissue just below the epidermis. Some of the cells in this tissue also contain druse crystals. [9]

Flowering structures

The flower clusters known as inflorescences grow on the ends of the stems and typically have three to five flowers each. The flowers are arranged such that there are longer flower stems (pedicels) on the outer flowers than on the inner ones. This gives the cluster a flat top and forms a structure called a corymb. The specialized bract leaves, which surround the flowers, are long and have glands and small hairs called cilia. The leafy structures that provide support for the petals, called the sepals, are roughly 0.2 cm (0.08 in) long, are an oblong shape, and can either be pointed or rounded. Their edges also have glands and small hairs, similar to the bracts. However, they may also have amber-colored dots and lines, which the bracts lack. [2] [3] The petals are yellow, like the type species of Hypericum , [10] and grow in a pentagonal arrangement on each flower. [4] They are 0.4–0.7 cm (0.2–0.3 in) long and have amber-colored glands that are shaped like dots or short lines. On the edges of the petals there are a few black glands in addition to the amber-colored ones. [2] [3]

The pollen grains of Hypericum sechmenii have three grooves in a triangular layout, and the overall shape of the grain is a slightly elongated sphere. An individual grain is 17.2 micrometers (μm) long and 11.5 μm wide. Each surface groove is 12.2 μm long and 2.4 μm wide, and the space where the grooves meet is 1.7 μm in diameter. There are pores on the surface of the pollen that are 2.5 μm long and 2.2 μm wide. Surrounding the grain is a tough outer wall that is 1.5 μm thick and has an outer layer with a net-like pattern. [11]

The seed capsules are 0.3–0.4 cm (0.12–0.16 in) and oblong in shape, and their ovaries have a few oil cavities that run lengthwise along the capsule. The seeds themselves have tiny, regularly-spaced pits that form patterns similar in appearance to small lines or ladders. [3]

Hypericum sechmenii usually flowers from June to July, and it fruits in July. [3]

Similar species

Hypericum sechmenii is similar in appearance to other Turkish species of Hypericum. In its original description, its similarity to Hypericum huber-morathii and Hypericum minutum was noted, and it has also been compared to Hypericum thymopsis . [3] [12]

When compared to Hypericum minutum and H. huber-morathii, H. sechmenii has differences in its leaves, flowers, and pollen grains. Its leaves are adjacent to one another on the stem and overlap, while the leaves of H. minutum and H. huber-morathii are placed on opposite sides of the stem and do not. H. sechmenii has more flowers on an inflorescence (3–5) than H. minutum (1–3), but usually has fewer than H. huber-morathii (3–12). The glands on its petals are also different; H. sechmenii has amber-colored dots and lines, whereas H. minutum has amber-colored dots with no lines and H. huber-morathii only has black dots, or no visible glands at all. Pollen grains are another way to tell the three species apart. H. minutum has tiny protrusions on the surface of its pollen called microspinae, which H. sechmenii lacks, and H. minutum also has far fewer distinct grooves on its surface. H. sechmenii pollen grains are larger than those of H. minutum and smaller than those of H. huber-morathii. H. huber-morathii has a slightly larger region on the end of the grain where the grooves meet. [13]

Anatomically, Hypericum sechmenii is also similar to H. thymopsis despite not being as closely related. Both species have similar stomata that make them able to thrive in dry climates, and both have stomata on the upper and lower sides of their leaves. However, the structure of the species' stem tissue sets them apart. H. sechmenii has a thinner layer of palisade tissue and its inner stem region is made up solely of xylem, whereas H. thymopsis has softer, spongy pith tissue as well. [12]

Taxonomy

Hypericum sechmenii was first observed and collected by the Turkish botanist Atila Ocak in 2006. The holotype of the species was collected in that same year by Ocak in the district of Günyüzü and is now housed at Eskişehir Osmangazi University. [3] [14] Three years later, in December 2009, the species was formally described by Ocak and Onur Koyuncu in the journal Annales Botanici Fennici . The authors gave the species the specific epithet sechmenii as an homage to the prominent Turkish taxonomist and ecologist Özcan Seçmen. In Turkish, the plant is called seçmen kantaronu, translated as Seçmen's St John's wort. [15] [3] The species was incorporated into the Flora of Turkey endemic species registry in 2011 alongside another recently described Hypericum species, Hypericum musadoganii . [16]

In 1977, the British taxonomist Norman Robson began a monograph of the entire genus Hypericum. He divided the genus into 36 sections, with almost every species in the genus placed into one of these sections based on their morphology and early applications of molecular phylogenetics. [17] However, Hypericum sechmenii was not included in this original monograph, as it had not yet been identified as a unique species. Robson later corroborated the findings of Ocak and Koyuncu that H. sechmenii was its own species, taking note of its similarities to other Anatolian species of Hypericum, specifically Hypericum minutum and Hypericum huber-morathii. Because of this, Robson placed the species in a clade called the Huber-MorathiiGroup. The group comprises five Turkish species of Hypericum and lies within the large section Adenosepalum . The placement of H. sechmenii was summarized by Robson as follows: [2]

Hypericum
Hypericum subg. Hypericum
Hypericum sect. Adenosepalum
Huber-MorathiiGroup
H. decaisneanum - H. formosissimum - H. huber-morathii - H. minutum -H. sechmenii

Distribution and habitat

Hypericum sechmenii is one of around 45 species of Hypericum that are endemic to Turkey. [18] Specifically, the species has been found in central Turkey within Eskişehir Province, [15] [19] at two separate localities: one near the peak of Arayit Mountain, and the other between the towns of Kaymaz and Sivrihisar. [3] [2] The area of distribution on Arayit Mountain is estimated to be 2 km2 (0.8 sq mi). The area of the Kaymaz to Sivrihisar locality is estimated to be smaller. [20]

The species' habitat is usually in and among the crevices of limestone rocks and outcroppings. The general elevation of the species is 1,750–1,820 m (5,740–5,970 ft). [2] [3] Several other specimens of Hypericum sechmenii have been collected since the species' discovery and are preserved at various Turkish herbariums. [21]

Table of collected specimens of Hypericum sechmenii
TypeDistrictLocalityHabitatCoordinatesCollection DateHerbariumReference
Holotype Günyüzü Arayit Mountain Rock crevices39°18'14"N, 31°44'51"E10 June 2006 Eskişehir Osmangazi University [22]
Isotype [note 1] GünyüzüArayit MountainRock crevices39°18'14"N, 31°44'51"E10 June 2006 Gazi University [21]
IsotypeGünyüzüArayit MountainRock crevices39°18'14"N, 31°44'51"E10 June 2006 Hacettepe University [21]
Sivrihisar Arayit MountainHilly steppe39°17'47"N, 31°45'07"E7 July 2011 [4]
SivrihisarSivrihisar–Kaymaz Rocks near Kaymaz31°13'56"N, 39°32'19"E13 July 2011 [4]
  1. ↑ An isotype is a duplicate collection of the holotype.

Ecology

The leaves of Hypericum sechmenii contain xeromorphic stomata, pores that have adaptations to allow the plant to better survive in its arid, steppe habitat of Central Anatolia, [23] [24] defined as the Irano-Turanian floristic region. [25] H. sechmenii has two adaptations of the genus Hypericum that deter grazing. The first is the presence of numerous black glands on the leaf margins; in other species of Hypericum, similar glands have been shown to contain compounds that are toxic to creatures consuming the plant. [8] The second is the presence of druse crystals in cells of the stem and leaf tissue. [6] These contain minerals that are thought to deter some insects from grazing. [7]

Hypericum sechmenii grows alongside small shrubs and perennial herbs like stonecress ( Aethionema subulatum ), woodruff ( Asperula nitida ), harebell ( Asyneuma compactum ), small toadflax ( Chaenorhinium minus ), Kotschy's damask flower ( Hesperis kotschyi ), flax ( Linum cariense ), restharrow ( Ononis adenotricha ), dandelions ( Scorzonera tomentosa ), Turkish catchfly ( Silene falcata ), and wood betony ( Stachys lavandulifolia ). It is found among only one other Hypericum species, that being Hypericum confertum . [26]

Conservation

The species is rare, with an estimated 250 surviving plants of the species in an area assumed to be smaller than 10 km2 (4 sq mi). The species is under threat from both abiotic factors, especially climate change, as well as human impact from agriculture and the grazing of domesticated animals. Because of these threats and the unsustainably small population size of Hypericum sechmenii, biologists from the Eskişehir Osmangazi University recommended that the species be classified as Critically Endangered by the International Union for Conservation of Nature, although no conservational measures had been taken as of 2013. [20]

Related Research Articles

<i>Hypericum</i> Genus of flowering plants known as St. Johns worts

Hypericum is a genus of flowering plants in the family Hypericaceae. The genus has a nearly worldwide distribution, missing only from tropical lowlands, deserts and polar regions. Many Hypericum species are regarded as invasive species and noxious weeds. All members of the genus may be referred to as St. John's wort, and some are known as goatweed. The white or pink flowered marsh St. John's worts of North America and eastern Asia are generally accepted as belonging to the separate genus TriadenumRaf.

<i>Hypericum socotranum</i> Species of flowering plant

Hypericum socotranum is a species of flowering plant in the Hypericaceae family which is endemic to the island of Socotra in Yemen. Its natural habitats are subtropical or tropical dry forests and rocky areas.

<i>Hypericum grandifolium</i> Species of flowering plant in the St Johns wort family Hypericaceae

Hypericum grandifolium, the large-leaved St John's wort, is a species of flowering plant in the family Hypericaceae. The plant is a bushy shrub that can grow to almost 2 meters tall. It has large leaves, golden yellow petals, and seed capsules that split open. H. grandifolium is native to the Canary Islands and Madeira in Macaronesia, but has become invasive in other regions, including California, after escaping from cultivation as an ornamental plant. It is parasitized by wasps and fungi, and is capable of reproducing through its rhizomes.

<i>Hypericum aegypticum</i> Species of flowering plant in the St Johns wort family Hypericaceae

Hypericum aegypticum is a species of flowering plant of the St. John's wort family (Hypericaceae) which is native to the Eastern Mediterranean. It was described by Carl Linnaeus in the second volume of his Species Plantarum in 1753, who named it after Egypt despite it not being distributed there. The plant is commonly known as shrubby St. John's wort or Egyptian St. John's wort in English. Like other members of section Adenotrias, it is found among limestone rocks in coastal areas. While it has been evaluated as threatened on the island of Malta, the species has no legal protections.

Hypericum collinum is a flowering plant in the family Hypericaceae which is found in Mexico.

<i>Hypericum bupleuroides</i> Species of flowering plant in the St Johns wort family Hypericaceae

Hypericum bupleuroides is a species of perennial flowering plant in the St John's wort family, Hypericaceae. It grows 45–80 centimeters tall, and notably has perfoliate leaves that are fused at the stem. It has pyramid-shaped flower clusters of 1 to 25 flowers with yellow petals in a star-shaped arrangement. The species is found along the Black Sea coast near the Turkish–Georgian border. Hypericum bupleuroides has a small distribution and specific habitat requirements that make it vulnerable to environmental pressures.

<i>Hypericum foliosum</i> Species of flowering plant in the St Johns wort family Hypericaceae

Hypericum foliosum, the shining St John's wort, is a species of flowering plant in the family Hypericaceae. It is a bushy shrub endemic to the Portuguese Azores Islands with golden yellow petals and many stems. The species was described by William Aiton in 1789 and was later placed into section Androsaemum of the genus Hypericum by Norman Robson in 1984. It has a diverse essential oil profile made up mostly of monoterpene hydrocarbons, and significant concentrations of various medicinally useful phenols and carotenoids. Populations of the plant are small in number, but quick to colonize cleared areas like groves, landslide areas, and volcanic ash deposits. It is parasitized by fungus and by moth species, but is not considered endangered by the IUCN. H. foliosum is used in traditional medicine on the Azores for diuretic, hepatoprotective, and antihypertensive purposes. It also has in vitro antibiotic and antioxidizing capabilities.

Hypericum cuisinii is a perennial herb in the genus Hypericum, in the section Adenosepalum. The herb has pale yellow flowers and occurs in Greece and Turkey.

<i>Hypericum <span style="font-style:normal;">sect.</span> Adenosepalum</i> Group of flowering plants

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<i>Hypericum formosissimum</i> Species of flowering plant in the St Johns wort family Hypericaceae

Hypericum formosissimum is a species of flowering plant in the family Hypericaceae, section Adenosepalum, in the Hypericum huber-morathii group.

<i>Hypericum huber-morathii</i> Species of flowering plant in the St Johns wort family Hypericaceae

Hypericum huber-morathii is a species of flowering plant in the St John's wort family Hypericaceae. It is a small perennial herb with few stems. It has narrow and brittle stems, thick leaves, flowers in clusters of varying numbers, small yellow petals, around twenty stamens, and three styles. H. huber-morathii is closely related to H. minutum and H. sechmenii, and also shares characteristics with H. lanuginosum. The plant is endemic to Turkey, and is found among limestone rocks in a limited region of southwestern Anatolia. Originally excluded from a comprehensive monograph of Hypericum, the species' placement within the genus is unclear. It has been placed in both section Adenosepalum and section Origanifolium.

<i>Hypericum aucheri</i> Species of flowering plant in the St Johns wort family Hypericaceae

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<i>Hypericum russeggeri</i> Species of flowering plant

Hypericum russeggeri is a species of flowering plant in the St John's wort family Hypericaceae. The plant is a small shrub with many branches that spread across the ground, and it has many small flowers with pale yellow petals. It is found only among calcareous rocks along the coast and in the foothills of the Nur Mountains of eastern Turkey and northern Syria. While H. russeggeri has an array of phytochemicals present in its flowering structures and leaves, these are found in lower concentrations than other species of Hypericum. The species was first described in 1842 as Triadenia russeggeri, and it has been placed into various defunct genera including Elodea and Adenotrias. It is now known as Hypericum russeggeri and is one of three species in Hypericum section Adenotrias with H. aegypticum and H. aciferum.

Hypericum minutum is a species of flowering plant in the St John's wort family Hypericaceae. It is a small perennial herb that grows in tufts. It has slender and brittle stems, flowers in clusters of one to three, yellow petals with black and amber glands, few stamens, and a seed capsule with narrow grooves. H. minutum is closely related to H. huber-morathii and H. sechmenii and resembles a smaller form of the latter plant. The plant is endemic to Turkey, and is found among limestone rocks in a limited region of southwestern Anatolia. Originally excluded from a comprehensive monograph of Hypericum, the species' placement within the genus is unclear. It has been placed in both section Adenosepalum and section Origanifolium.

<i>Hypericum coadunatum</i> Species of flowering plant of the St. Johns wort family

Hypericum coadunatum is a species of flowering plant of the St. John's wort family (Hypericaceae) that is found in the Canary Islands.

Hypericum psilophytum is a species of flowering plant of the St. John's wort family (Hypericaceae) that is found in Morocco and Algeria.

Hypericum somaliense is a species of flowering plant of the St. John's wort family (Hypericaceae) that is found in Somalia.

<i>Hypericum tomentosum</i> Species of flowering plant of the St. Johns wort family

Hypericum tomentosum is a species of flowering plant of the St. John's wort family (Hypericaceae) that is found in the western Mediterranean.

<i>Hypericum decaisneanum</i> Species of flowering plant of the St. Johns wort family

Hypericum decaisneanum is a species of flowering plant of the St. John's wort family (Hypericaceae) that is found in the Libya.

References

  1. ↑ Yaylaci et al. 2013, p. 4.
  2. 1 2 3 4 5 6 7 Pattinson, David; Robson, Norman; Nürk, Nicolai; Crockett, Sarah. "Hypericum sechmenii Nomenclature". Hypericum Online (hypericum.myspecies.info). Archived from the original on 13 February 2021. Retrieved 5 February 2021.
  3. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Ocak et al. 2009, p. 592.
  4. 1 2 3 4 Yaylaci et al. 2013, p. 3.
  5. ↑ Yaylaci et al. 2013, pp. 7–8.
  6. 1 2 3 Yaylaci et al. 2013, p. 7.
  7. 1 2 Cuéllar-Cruz et al. 2020, p. 596.
  8. 1 2 Crockett & Robson 2011, p. 4.
  9. ↑ Yaylaci et al. 2013, pp. 4–6.
  10. ↑ Pattinson, David; Robson, Norman; Nürk, Nicolai; Crockett, Sarah. "Hypericum perforatum Nomenclature". Hypericum Online (hypericum.myspecies.info). Retrieved 13 November 2023.
  11. ↑ Ocak et al. 2009, p. 593.
  12. 1 2 Tekin 2017, p. 151.
  13. ↑ Ocak et al. 2009, p. 592-593.
  14. ↑ Pattinson, David; Robson, Norman; Nürk, Nicolai; Crockett, Sarah. "Eskişehir Osmangazi Univ. – [node:field_collector] – 5345". Hypericum Online (hypericum.myspecies.info). Archived from the original on 13 February 2021. Retrieved 13 February 2021.
  15. 1 2 Güner, A.; Aslan, S.; Ekim, T.; Vural, M.; Babaç, M.T. (2013). "Türkiye Bitkileri Listesi (Damarlı Bitkiler)" [Turkish Plants List (Vascular Plants)]. Bizimbit Kiler (www.bizimbitkiler.org.tr) (in Turkish). İstanbul: Nezahat Gökyiğit Botanical Garden and Flora Research Association. Archived from the original on 13 February 2021. Retrieved 13 February 2021.
  16. ↑ Kaynak 2012, p. 5.
  17. ↑ Carine & Christenhusz 2013, p. 3.
  18. ↑ Tarihi, Tarihi & Tarihi 2019, pp. 253–268.
  19. ↑ Plants of the World Online (POWO) (2019). "Hypericum sechmeniiOcak & Koyuncu". Royal Botanic Gardens, Kew. Archived from the original on 8 February 2021. Retrieved 5 February 2021.
  20. 1 2 Yaylaci et al. 2013, pp. 8–9.
  21. 1 2 3 International Plant Names Index (IPNI) (2020). "Hypericum sechmenii Ocak & O.Koyuncu, Ann. Bot. Fenn. 46(6): 591 (−594; figs. ) (2009)". The Royal Botanic Gardens, Kew; Harvard University Herbaria & Libraries; and, Australian National Botanic Gardens. Archived from the original on 13 July 2022. Retrieved 5 February 2021.
  22. ↑ Ocak et al. 2009, pp. 591–592.
  23. ↑ Yaylaci et al. 2013, p. 5.
  24. ↑ Meteoroloji Genel Müdürlüğü, pp. 1–2.
  25. ↑ Talebi, Sajedi & Pourhashemi 2013, pp. 69–70.
  26. ↑ Ocak et al. 2009, p. 594.

Bibliography

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