| Iris orjenii | |
|---|---|
 | |
Scientific classification | |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Angiosperms |
| Clade: | Monocots |
| Order: | Asparagales |
| Family: | Iridaceae |
| Genus: | Iris |
| Subgenus: | Iris subg.Iris |
| Section: | Irissect. Pogon |
| Species: | I. orjenii |
| Binomial name | |
| Iris orjenii Bräuchler & Cikovac | |
| Synonyms | |
Iris orienii(lapsus) | |
Iris orjenii, theOrjen iris, is a rare species ofiris found inMontenegro andBosnia and Herzegovina on thekarst landscape ofOrjen mountain. It grows in the wild on grassy slopes at 1,500 to 1,700 m (4,900 to 5,600 ft), in sunny or semi-shaded locations withinBosnian Pine communities. It is a member of thesubgenusIris, meaning that it is a bearded iris, and grows from arhizome.
It has a fibrous and branched rhizome.[1]Theherbaceous leaves are bluish-green in color, and sword-shaped, and grow up to between 35–50 cm (14–20 in) long,[1][2] and 2.5 to 3 cm in width.[2] It has a slender stem orpeduncle, that can grow up to between 30–50 cm (12–20 in) tall,[2] and has several branches.[1] Theinflorescence (or blooms), are produced in April,[1] or June,[2] they are fan-shaped and contains two or three white flowers,[2] with a purple mark.[1]
Iris orjenii is exclusively confined toOrjen, the highest mountain of the coastalDinaric Alps, towering over theBay of Kotor in southwesternMontenegro. Heavy glaciated during thePleistocene period,glaciokarstic morphology dominates the higher portions of the mountain. Outstanding for intenseprecipitation averaging 5000 mm/a (maxima >8000 mm/a), Mount Orjen has by far the highest amount of rainfall in theMediterranean and also one of the highest in Europe.
Thetaxon shows a significant syntaxonomic affinity to open altimediterraneanpastures within the Seslerion robustae alliance and open Mediterranean mountainous coniferousPine woodland – Pinion heldreichii alliances. The examined partialpopulations grow under similar conditions on south facing slopes with abundant light. The new species is restricted to humid chromic luviccambisols and rendzicleptosols at localities above tree line in the oro- to altimediterranean lifezone between 1550 and 1750 m in the eastern Orjen.
While the great inlet of the Bay of Kotor winds deep into the High-Karst zone of Mt. Orjen, Mediterraneanclimate penetrates far inland. Profound mixtures of species from more than one climatic zone and in addition endemic and stenoendemicspecies and special vegetation types with marked transitional vegetation units restricted exclusively to ecotons of humid (Csa) subtropical and hyper humid oceanic- (Cfs) climates are especially notable. Mediterraneancyclones andsirocco storms are accountable for the heavy precipitation (up to 5000 mm/m2 atCrkvice, 940 m AMSL) that feeds the luxuriant and hyper-humid type of eastern Mediterranean vegetation comparable to colchidia-hyrcanian formations of theCaucasus andAsia Minor in the exceptionally damp and mild climate of the Montenegrin coast.
While humidity generally increases withaltitude, the vegetational structure oftransects on Orjen varies through a combination of ranges of warmth and humidity where altitude, exposition,geomorphology andpedology correlate with specificalliances in the vegetation. At coast level atRisan with up to 3500 mm/m2 precipitation per year the perhumid eumediterranean climate variant is established (Cs’’a climate; s’’= double winter rain season. According to the Köppen climate classification). Rain augments in the supra- to oromediterranean life zone (Crkvice at 940 m) to 4926 mm/m2 (Cfsb climate; fs= without summer dryness), while the higher summits of the alti- and kryomediterranean life zone receive more than 6000 mm/m2 per year and are constituents of mediterraneansnowclimates (Dfsc) heavily influenced bybora and sirocco storm winds.
Frequent coldmountain wave wind situations during winter associated with cold high pressure systems over the mainland prevail in the innermost Bay at Risan and vegetational zones are compressed by the impact of bora. In addition the thermophylic communities ofmaquies andphrygana formations show the noticeable absence of some mediterranean species.
The iris appears in following alliances:Seslerion juncifoliae Horvat 30 (with the vicariantSeslerion robustae (Horvat) Lakus. endemic to Orjen) in the association Carici laevi-Helianthemetum balcanici Horvat 30 and Seslerio robustae-Juniperetum hemisphaericae (Hor.) Kus. and the Pinion heldreichii (Horvat) Lakus. alliance in the associations Fritillario-Pinetum heldreichii M. Jank. and Peucedano-Pinetum heldreichii M. Jank.According to preliminary observations two different subunits should be separated and both communities should be regarded as sub-associations within a united community. Apart from the subunit within Peucedano-Pinetum heldreichii M. Jank with notable altimediterranean Dinaric dry mountainous grassland and xerophytic tall herb taxa (Peucedanum longifolium,Senecio thapsoides ssp.visianianus andJuniperus nana (now a synonym ofJuniperus communis var.saxatilis Pallas)) on nottoo shallow rendzic leptosols at the bases of higher cliffs, there is in depressions with deep chromic luvic cambisols a mesophytic tall herb community with numerous humidity indicators within Seslerion robustae whereIris orjenii forms a community of its own with respect to its spectrum of diagnostic species as well as its physiognomic structure. Associated species areHeracleum sphondylium,Lilium martagon var.cattaniae andAsphodelus albus. The appearance ofPaeonia daurica Andrews (syn.Paeonia mascula subsp.triternata Boiss.), as observed at the latter community and nearby scattered individuals ofBetula pendula andAcer heldreichii, underline that specially this part of Mt. Orjen belongs to the transitional oromediterranean type where the orophytic vegetation contains mixtures of submediterranean and temperate chorological elements.
Cross-breeding of closely related species belonging to different chorions as it was probably the fact with the putative parent species ofI. orjenii are thus readily explained by the driving climatological forces of scirocco and bora which induce vegetation mosaics of temperate and mediterranean elements at different altitudes. Thus the narrow zone of transitional climates and plant communities on Orjen is most noticeable expressed by several transitional plant communities and contains not only mixtures of species from more than one climatic zone, but in addition endemic and even stenoendemic species which are restricted to this transitional zone.
Two other species occur on Mt. Orjen,Iris pseudopallida Trinajstic andIris reichenbachii var.bosniaca (now classified as a synonym ofIris spuria,[3]), both with equal chromosome numbers (2n=24), same asIris orjenii.[1]I. orjenii appears somewhat intermediate, in height of stem, colour of flowers and consistence of spathes. The shape of the tepals is different fromI. pseudopallida but similar to those ofI. reichenbachii var. bosniaca. The spathe dries out before or during flowering time, getting white to slightly brownish, sometimes with a violet teint, a diagnostic feature for the whole Pallida series, whereas inI. reichenbachii the spathe is sharply keeled and stays completely green until flowering period is over. Shape of seed, a character regarded to be of high diagnostic value reveals similarity to those ofIris cengialti andIris illyrica, both closely related toI. pseudopallida, but striking dissimilarities to the latter, which has compressed seeds. Seeds ofI. reichenbachii are described to be similar to those ofI. orjenii. Shape and undulation of falls and standards are much more similar toI. reichenbachii, whereas no white flowered individuals from wild population of this species have been reported. White flowering plants ofI. pallida from the region ofDubrovnik and white flowering individuals have been spotted occasionally in bigger populations in southern Dalmatia. A hybrid origin ofI. orjenii might be suspected, the more as it is found exactly at the height where areals ofI. pseudopallida andI. reichenbachii potentially overlap.Thus the closestI. orjenii population was seen only 2 km from a remoteI. pseudopallida locality and I. reichenbachii is found in the immediate vicinity of all known stands ofI. orjenii. The morphological homogeneity ofI. orjenii and the ecological specialisation also favour exclusion of a spontaneous hybrid population hypothesis. I. orjenii is fully fertile and generative propagation in situ has been examined.The new species is restricted to humid chromic luvic cambisols in the high altimediterranean level. The eu- to supramediterraneanI. pseudopallida in contrast is widespread on bare limestones or initial rendzic leptosols (Rendzina) in a variety of mediterranean and submediterranean alliances of coastal karst plains, on megacliffs in the Ephedero-Cyxthoselinetum palmoidis alliance and on montane limestone escarpments in the Campanula-Moltkeetum petaeae H-Iċ alliance.I. reichenbachii var.bosniaca andI. orjenii have strong affinities in their phytosociological character as they are constituents of Festuco-Seslerietea Barbéro & Bonin 1969 withI. reichenbachii var.bosniaca common inSeslerietalia juncifoliae H-at andCrepedetalia dinaricae Lksic. associations on shallow rendzic leptosols of Dinaric high altitudinal limestone pastures and Pinion heldreichii alliances. But ecological differences exist asI. orjenii is never found on extremely shallow soils.Concluding from both morphology and ecology, a hybrid origin followed by speciation seems the best explanation for the restricted occurrence ofI. orjenii.