Abies delavayi Franch.

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Credits

Tom Christian (2021)

Recommended citation
Christian, T. (2021), 'Abies delavayi' from the website Trees and Shrubs Online (treesandshrubsonline.org/articles/abies/abies-delavayi/). Accessed 2021-10-24.

Genus

Common Names

  • Delavay Fir
  • cang shan leng shan

Glossary

assurgent
Curving or growing upwards.
dbh
Diameter (of trunk) at breast height. Breast height is defined as 4.5 feet (1.37 m) above the ground.
herbarium
A collection of preserved plant specimens; also the building in which such specimens are housed.
revolute
Rolled downwards at margin.

Credits

Tom Christian (2021)

Recommended citation
Christian, T. (2021), 'Abies delavayi' from the website Trees and Shrubs Online (treesandshrubsonline.org/articles/abies/abies-delavayi/). Accessed 2021-10-24.

Tree 30–40 m × 1–1.5 m dbh. Crown pyramidal in young trees, broad-pyramidal later; flat-topped, often irregular in old trees. Bark reddish-brown and smooth at first, deeply fissured with age breaking into irregular plates. First order branches spreading horizontally, slightly descending with age; second order branches horizontal or assurgent. Branchlets stout, assurgent, maroon- or reddish-brown (rarely purplish-brown) maturing grey-brown then grey, weakly ridged at first, soon smooth, glabrous or initially puberulent in grooves. Vegetative buds ovoid-globular, small and resinous except on leading shoots. Leaves densely set in several overlapping ranks, radially outspreading on leading shoots, parted above and below by a narrow ‘V’ on weaker shoots,1.2–3.5 cm long, 1–2 mm wide, base twisted, margins strongly revolute (sometimes partially obscuring stomatal bands on the underside), apex emarginate or obtuse, glossy dark green above, with two chalk-white stomatal bands beneath. Pollen cones 2–4 cm long, yellow with violet microsporophylls. Seed cones 6–11(–14) cm × 3–4.5 cm, apex abruptly rounded to ~truncate, dark indigo-blue at first, maturing purplish-black or blackish-brown; seed scales ~flabellate, 1.7–2 × 1.8–2.2 cm at midcone; bracts oblong-spathulate with a long narrow cusp, prominently exserted during development but usually only the cusps exserted at maturity. Rachis thick, conical-fusiform, purplish-brown. (Farjon 2017Fu et al. 1999).

Distribution  Myanmar North China SE Xizang (Tibet), W Yunnan India Extreme NE

Habitat Mountain forests at 2400–4300 m asl, characterised by cool summers and very high precipitation (1000–3000 mm annually). Occasionally in pure stands at altitude but usually mixed with other conifers, including Tsuga spp. at lower elevations, and Picea spp. at higher elevations.

USDA Hardiness Zone 7-8

RHS Hardiness Rating H6

Conservation status Least concern (LC)

It is probable that the first introduction to western gardens of Delavay Fir in the strict sense (viz. A. delavayi var. delavayi sensu Farjon 1990, 2001, 2017), was one of Forrest’s gatherings, but it is unclear which. He collected the species on multiple occasions on nearly all his expeditions to China (often only for the herbarium) in its type locality near Dali, in the Mekong Valley, and in Myanmar, and his gatherings may represent both A. delavayi and A. nukiangensis. How many of his collections resulted in living plants is unclear; Bean suggested that it was probably ‘not in cultivation in its typical state’ (Bean 1976a) but given the taxonomic confusion surrounding the species and the sheer volume of Forrest’s gatherings, this seems unlikely. For some time it was thought that Wilson had collected this in 1910 under W 4078, but this is A. fabri. Indeed, it appears quite unlikely that Wilson ever introduced A. delavayi.

Bean did add that ‘It might, however, still be found if any trees survive from Forrest’s 30975, collected in the type locality on his last expedition [1930]’ (Bean 1976). This could be the source of the oldest trees extant in collections, for example a tree near the Golden Gates at Benmore Botanic Garden in Scotland (accession 19588923*A, 13 m × 0.5 m dbh in 2018), and the experimental forest plot at nearby Kilmun Arboretum, planted in 1932. The best (edge) trees at Kilmun were 17 m × 0.65 m dbh in 2017, slightly smaller than those remaining from a similar plot at Brechfa, Wales (20.8 m in 2018) which are probably the largest in cultivation (Tree Register 2020).

A. delavayi was targeted by several other well-known collectors through the 20th century, including Kingdon-Ward, Ludlow, Sherriff & Taylor, and Rock, most often for the herbarium; few if any trees can be traced to their gatherings. More recent collections that have resulted in meaningful numbers of plants include those of the Sino-British Expedition to the Cangshan (SBEC 0505), the Kunming-Gothenburg Expedition (KGB 799), Patterson & Main (P&M 89) and the Chungtien, Lijiang & Dali Expedition (CLD 1301).

FED (sometimes given as EGE) 226 was collected as A. delavayi on the Forestry Commission/RBG Edinburgh Dêqên Expedition in 1995, and it is still occasionally seen so-labelled in collections, but this belongs to A. ferreana or A. georgei. Material from the type locality on Cangshan was introduced to the Arnold Arboretum in 2001 (plant id 11–2001), but none of Wilson’s many introductions made under this name from western Sichuan (W 4078, 4082, 4086, 4396) will be genuine. In any case, it is likely that the Massachusetts climate is far too harsh for it, but it may be grown in cooler parts of the North American west coast.

Several authors have recalled meeting A. delavayi on the Cangshan, but perhaps none quite so vividly as Roy Lancaster who saw it there on the SBEC expedition and who noted the gradual and subtle changes caused by increasing altitude; the needles becoming shorter and more strongly revolute the higher they went, and the branchlets themselves become significantly more assurgent with altitude (Lancaster 2008 p. 224).

In cultivation none of the Sino-Himalayan firs enjoy dry conditions, but A. delavayi and its close relatives seem to be more sensitive than most. Even in the UK’s maritime climate the best examples by far may be found in western gardens that receive abundant rainfall. Another consideration in siting it is that in youth it is not quite as hardy as some of its compatriots. In Scotland, numerous examples of CLD 1301, gathered from the Cangshan, were planted at Dawyck Botanic Garden in the mid to late 1990s, together with multiple collections of A. forrestii, A. georgei, A. fabri, A. fargesii, etc. Dawyck is a notoriously cold garden in a Scottish context, and while all the latter species have thrived, each individual of A. delavayi has suffered from the recurring loss of leading shoots after being cut back by late frosts, in spite of their position on steep slopes. (pers. obs. 2008–2020). Had they been planted at Benmore Botanic Garden, in the much milder county of Argyll in western Scotland, they would likely by now have made handsome young trees.


Abies delavayi agg. in Arunachal Pradesh

The diversity of firs in Arunachal Pradesh, and in adjacent south east Xizang (Tibet), across the Brahmaputra / Yarlung Tsangpo watershed, remains imperfectly known. In Bhutan and westernmost Arunachal Pradesh we find A. densa; to the east, in northwest Yunnan, northern Myanmar, perhaps in extreme southeast Tibet near the Yunnan border, and in eastern Arunachal Pradesh, we find A. delavayi agg. Where and how these two species meet and give way to one another in the mountains across the north of Arunachal Pradesh is poorly understood.

Specimens from this area, and across the watershed in Tibet, are deposited in herbaria under a multitude of names. The following, for example, are all from the north of the watershed in south east Tibet: L&S 1572 from ’Kyimpu’, collected as A. delavayi though clearly not that species; KR 3372 from Mainling Xian collected as A. delavayi var. motuoensis; KR 3202 from Motuo Xian and Kingdon-Ward 5674 from Nyingchi Diqu, both collected as A. densa.

  • Abies delavayi var. motuoensis This name causes something of a problem. It was applied to specimens collected to the north of the watershed, in Motuo Xian (or Motuozhen) in Mêdog County in south east Tibet. Material was gathered there by an unnamed Chinese collector, number 1011, and the type specimen is deposited in Beijing. It is apparently distinguished from the A. delavayi by its densely pubescent, paler shoots (Cheng, Fu & Cheng 1975) however its placement in A. delavayi raises some problems. First, it is the only representative of the A. delavayi aggregate reported from north of the Yarlung Tsangpo / Brahmaputra watershed; second, no known collection originating from north of that watershed exhibits the revolute needle margins common to every other member of the delavayi aggregate; finally, the reference in the original description to paler shoots further distances it from every other member of the delavayi aggregate as presently understood (viz. A. delavayi, A. fansipanensis, A. nukiangensis).

Kingdon-Ward 21008, from northern Myanmar, is the only collection seen during research for the present work that combines the revolute needle margins of the delavayi aggregate with hairy shoots (pers. obs). It has previously been attributed to A. nukiangensis (which also combines those characters) but exhibits subtle differences. As we have seen hairy shoots are a key character of var. motuoensis, but that taxon’s type locality and that of KW 21008 are separated by over 200 km and considerable tracts of inappropriate habitat. Hairy forms of A. delavayi agg. (viz. A. nukiangensis) clearly exist in northern Myanmar but these cannot be assigned to Cheng & Fu’s var. motuoensis because, although hairy, they have dark shoots. Several major works of recent years have made much of the hairiness of var. motuoensis, but in so doing have overlooked the important character of pale shoot colour (e.g. Farjon 1990, 2017). Indeed, this character is a curious commonality between var. motuoensis and A. fordei.

Rushforth’s publication of A. fordei offers a useful overview of some of the barriers to pollen and seed dispersal in the genus, especially in the topographically complex Sino-Himalayan area, and prominent among these is that the high passes that dissect the Yarlung Tsangpo / Brahmaputra watershed cannot support Abies forest (Rushforth 2009). This is not to say that in a warmer past they did not permit, even just briefly, north-south gene flow between these two regions, which could have subsequently led to speciation on either side, but this is conjecture, and it remains the case that no collection from north of this watershed exhibits the revolute needle margins common to every other known member of the delavayi aggregate, even in the widest sense.

The most likely explanation is that Cheng & Fu fell into the common trap of using A. delavayi s.l. as a taxonomic placeholder for poorly understood entities. Whilst the entity they intended to circumscribe with the name motuoensis may well exist and may well be distinct, it is likely nothing to do with A. delavayi. It is probably part of the variation of A. fordei, and recognising it as such would provide a name for particularly hairy collections of A. fordei which Rushforth cites in his protologue, but cautions may be ‘different’ (Rushforth 2009; see also A. fordei).

Turning our attention back south of the watershed, to Arunachal Pradesh, Ludlow, Sherriff & Taylor 3474, deposited at Edinburgh (E00005157), was collected above Mechuka in 1938 and fits A. delavayi agg. (as labelled) in its prominently revolute needle margins, but not in its yellowish and prominently ridged shoots, which suggest A. densa. Something of a half-way house, it may still be in cultivation. KR 10386 is from the same area and is more accurately labelled ‘A. densa agg.’ in the few collections where it is grown. KR 9980 and 10794 are from further east in the state, and are probably best labelled A. nukiangensis aff. for the time being.


'Major Neishe'

Synonyms / alternative names
Abies delavayi 'Buchanan'
Abies delavayi 'Buchanan's Dwarf'
Abies delavayi 'Nana'

Abies delavayi ‘Major Neishe’ is a rare example of a cultivar of a Sino-Himalayan fir. It is a dwarf plant of irregular habit and very slow growth, which only begins to add meaningful height after several decades. It was raised at the Hillier nurseries in the 1930s, perhaps from seed gathered on Forrest’s last expedition, and distributed to Major Neishe’s property in Scotland. For some time ‘Buchannan’ was considered to be synonymous with this clone, but some now point to a distinct origin, this clone having been sent to Hilliers from another Scottish collection in 1972 (Auders & Spicer 2012). The time-lapse permits conjecture that Mr Buchanan’s plant had itself been propagated from ‘Major Neishe’! It is doubtful this question will ever be resolved, and it matters little, for to all intent and purpose these two names represent exactly the same aberrance, differing only in minute details, and one name is amply sufficient.


'Midnight Blue'

Abies delavayi ‘Midnight Blue’ has cones of a somewhat less intense, more pruniose blue than is typical for the species. The foliage is also not so dark green as usual. The habit is similar to that of ‘Major Neishe’ in that it is a distinctly dwarf selection; the original tree remained only 40 cm tall after ten years. Whether it will later add height, as ‘Major Neishe’ does, remains to be seen. It was selected from a batch of seedlings raised in Scotland in 1996, named and put into commerce by the late Derek Spicer (Auders & Spicer 2012). It seems to have had only a very limited distribution, and remains very rare.