Introduction

The following detailed report addresses the taxonomic, morphological, ecological, and distributional considerations of Noaea mucronata subsp. humilis (Boiss.) Danin & Raus (fig.1.) compared to Noaea mucronata subsp. mucronata, with a special focus on whether subsp. humilis should be regarded as endemic to Lebanon and Syria. This stems from your overarching study on plant species that are endemic to Lebanon, Syria, or both. You have chosen to follow the classification proposed by Danin & Raus (2012), which recognizes subsp. humilis as a valid subspecies distributed from Lebanon and Syria eastward into Iran. Consequently, it cannot be considered endemic to Lebanon and Syria alone.

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Abstract
Noaea mucronata subsp. humilis (Boiss.) Danin & Raus is a dwarf, cushion-form plant occurring above 1700 m in Lebanon, Syria, and Iran. It differs from subsp. mucronata in its purple coloration during anthesis, reduced stature (10–20 cm vs. up to ~75 cm), and adaptation to cold, windy montane habitats rather than lower-altitude steppes. Because these populations extend beyond Lebanon and Syria, subsp. humilis is not endemic to those two countries, and we have excluded it from local endemics following Danin & Raus (2012). Nevertheless, its role in subalpine cushion-plant communities (tragacanth formations) remains ecologically significant for conservation efforts in the Levant.

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1. Taxonomic and Historical Context

1.1 Original and Early Classifications

• Forsskål (1775)
  The basionym Salsola mucronata Forssk. (1775) underpins today’s Noaea mucronata. Over time, related synonyms appeared, including Anabasis spinosissima L.f. and Noaea spinosissima (L.f.) Moq.

• Boissier (1879)
  Recognized distinct mountain populations as Noaea spinosissima var. humilis in Flora Orientalis (4: 965), pointing to their dwarf, cushion-like form in higher altitudes.

• Dinsmore (1933) and Mouterde (1966)

  • Dinsmore: Noaea mucronata var. humilis in Flora of Syria, 2nd ed., Vol. 2, p. 451.

  • Mouterde: In Nouvelle Flore du Liban et de la Syrie, Tome Premier (p. 435), describes a “forme montagnarde à tiges courtes, en coussinets,” i.e., a compact, cushion-plant morphology.

• Aellen (1953)
  Reduced these mountain forms to Noaea mucronata f. humilis (Boiss.) Aellen in Mitt. Basler Bot. Ges. 1(1): 12, implying a minor variation (forma) of N. mucronata.

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1.2 More Recent Revisions

• Assadi (1999)
  In A revision of the genus Noaea Moq. (Chenopodiaceae) in Iran (Iranian Journal of Botany 8: 23–33), did not recognize humilis as distinct, subsuming it under Noaea mucronata. Assadi recognized three subspecies (subsp. mucronata, subsp. tournefortii, subsp. leptoclada) but placed humilis in synonymy.

• Danin & Raus (2012)
  In Med-Checklist Notulae, 31 (Willdenowia 42: 287–295), elevated this taxon to Noaea mucronata subsp. humilis (Boiss.) Danin & Raus, stat. nov. They based this on:

  • ~45 years of comparative field observations (mountain vs. lowland forms),

  • clear morphological (purple coloration, dwarf habit) and ecological contrasts (high-altitude, cushion vegetation),

  • phyto-sociological differences (tragacanth formations).

• Acceptance in Major Databases

  • Kew (POWO): Shows subsp. humilis as a valid taxon distributed in Lebanon, Syria, Iran, etc.

  • WFO (World Flora Online): Incorporates Kew’s data, thereby also accepting subsp. humilis.

  • GBIF: Reflects a mixture of older synonyms (f. humilis) and the newer subspecies rank, depending on data sources.

  • Euro+Med: Includes subsp. humilis within its geographic plant lists for the Eastern Mediterranean region.

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2. Morphological Details

2.1 Mouterde’s (1966) Description

From Nouvelle Flore du Liban et de la Syrie, Tome I, p. 435 (summarizing/paraphrasing key points):

Noaea mucronata (Forsk.) Asch. et Schweinf.
Salsola mucronata Forsk. 1775, Anabasis spinosissima L.f., Noaea spinosissima (L.f.) Moq.

• Shrub, ~30–40 cm tall, glabrous, branching from the base.

• Trunk/branches with grayish bark, fissured. Younger shoots yellowish-green, flexuous, papillo-scabrous.

• Leaves alternate, green to glaucous, linear (6–22 mm), eventually rigid, spiny-tipped.

• Floral leaves short, membranous-scarious at base, acute-mucronate.

• Flowers solitary in leaf axils, 5-membranous sepals (4 mm at anthesis).

• Fruiting perianth: with membranous wings, white to purple.

Var. humilis (Boiss.) Dinsm.: A “forme montagnarde à tiges courtes, en coussinets,” i.e., a dwarf cushion form at higher, drier elevations, flowering July–August, fruiting in autumn/winter.

 

 2.2 Comparison with subsp. mucronata

Below is a table consolidating the key morphological contrasts between subsp. humilis and subsp. mucronata: