Primula cusickiana var. maguirei in Utah

Logan Canyon

While heading to southern Utah just before Easter,2016, I stopped in to Logan Canyon. The entrance to this canyon lies just beyond Utah State University in the town of Logan, Utah. Scenic byway 89 follows the canyon and the Logan river that flows through this cut in the Bear River Mountains, a branch of the Wasatch Range, right through to Bear Lake. The cliffs are nearly vertical limestone and are home to Primula maguirei. At this time of year, the canyon is still very cold, particularly on the north, shaded side and icy snow lingered on the path. This Primula was just waking up, though we managed to find one plant with a single flower bud, it is obvious that this species won't bloom until much later in May. It was growing as a chasmophyte, in thin crevices in the rock and was difficult to find, being out of flower and the leaves not yet fully expanded.


Pointing out tiny P. maguirei

I was curious about this species as it is now considered a variation of P. cusickiana along with P. domensis and P. nevadensis. Certainly without referencing a key and despite the plants being in early growth their close relationship to P. cusickiana was obvious. Noel Holmgren and Sylvia Kelso address this complex of species in their paper "Primula cusickiana (Primulaceae) and its varieties", Brittonia 53: 154-156. The Flora of North America key relies on merely the length of the corolla tube to distinguish the varieties, but the close relationships were determined by genetic study (unpublished, but see also "Are any primroses (Primula) primitively monomorphic?", Mast, Kelso, Conti, New Phytologist 171, issue 3: 605-616, 2006. It is noted that though Primula capillaris is also very closely related it has been kept as a distinct species. What is also interesting about these species is their specific habitats and very restricted distribution: P. cusickiana in sandy and clay soils among sagebrush in SW Idaho and NE Oregon, P. nevadensis on limestone screes above timberland in Eastern Nevada, P. maguirei on limestone outcrops along the bottom of Logan Canyon and P. domensis along limestone rocks in Western Utah.

Primula cusickiana (var. domensis) in cultivation
 

Pam Eveleigh © 2016

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Primula lilacina vs Primula bellidifolia (P. hyacinthina)

Primula lilacina

In 2008, Primula lilacina, a new species in Section Muscarioides was described by John Richards. This species is found in Sichuan (Tuer Pass 29°31'0.49"N 100°16'21.09"E and Yading area 28°26'57.86"N 100°20'47.06"E) and features leaves that are densely coated with thick white farina on the underside. It has the typical capitate inflorescence of members of this section though the flowers are relatively large.



Primula bellidifolia in Bhutan

Immediately it recalls the species Primula hyacinthina which was described from Tron, SE Tibet ( 28°19'45.94"N 92°54'11.80"E) in 1936 but which is now included within Primula bellidifolia. This starts ringing alarm bells for me as P. bellidifolia was described as having leaves which are pubescent on both sides and without farina whereas P. hyacinthina has a thick white coating of farina on the under surface of the leaves - just like P. lilacina!

P. lilacina (L), P. bellidifolia (R)

So why are P. hyacinthina and P. bellidifolia lumped together? If we look to the field notes of the Ludlow & Sherriff collection #5635 from the Tse La, Tibet ( 28°49'19.88"N 93°42'33.93"E), they note that though the collection is identified as P. hyacinthina and the leaves have white farina on the underside, a few plants in the population showed no farina on the leaves. In cultivation, some of the leaves on the same plant of P. hyacinthina can be occasionally be efarinose or nearly so and sometimes typical P. bellidifolia produces farina on the petiole and base of the leaves. It seems then that we are looking at a complex of variable plants, and this is seen in the large number of synonyms for P. bellidifolia (P. adenantha, P. atricapilla, P. hyacinthina, P. menziesiana, and P. micropetala), though all of these synonyms except P. hyacinthina are from a localized area in Bhutan. See an explanation by  R.E. Cooper. P. bellidifolia was originally described from Sikkim, but the species as a whole is distributed in a wide area from Eastern Nepal, through Bhutan into Arunachal Pradesh and Tibet (for P. hyacinthina). The type locations for P. hyacinthina and bellidifolia are 420kms apart. The herbarium sheets for P. hyacinthina are E00024548 and BM000996891.

 

What makes P. lilacina different from P. hyacinthina? It is unfortunate that Richards did not compare the two species when he described P. lilacina. The obvious difference  between the two is geography. The type locations for these two species are 750kms apart, and neither species seems to have been found in the intervening territory. In all other characters it seems they are equivalent.

 

Perhaps genetic study of these species will help to determine their relationships, but until we have more information it is expedient to keep P. lilacina as a distinct species. See more images in the Species Gallery.

 

Pam Eveleigh © 2016

 

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Bonvalot and d'Orléans in China

In 1889-1890 Gabriel Bonvalot and Prince Henri d'Orléans embarked on a journey from Siberia through Tibet and Yunnan ending in Tonkin (Vietnam). See Map. A detailed map is also available. Bonvalot's account of the journey is in the book "De Paris au Tokin a Travers Le Tibet Inconnu" which is translated into English in "Across Thibet". They were accompanied by Father Constant de Deken who acted as interpreter. His account of the journey is detailed in the book "A Travers L'Asie".

Botanical specimens were collected on the expedition, including several Primula species. These were described by the French botanists Adrien Franchet and Édouard Bureau of the Paris Muséum National d'Histoire Naturelle in a document "Plantes Nouvelles du Thibet et de la Chine Occidentale". The species are Primula vittata (synonym of P. secundiflora), Primula leptopoda (synonym of P. stenocalyx), Primula diantha (collection date should read 1890 not 1860) Primula henrici and Primula pycnoloba. These all have specific collection dates, with the exception of P. pycnoloba, so using Bonvalot's book and the maps above, we can find the approximate type locations. All the type specimens are in the Paris herbarium.

Primula pycnoloba

Two other species were collected by Prince Henri d'Orléans on another trip, this time from Tonkin to Assam in 1895. See Map in the book "From Tonkin to India by the sources of the Irawadi". They are Primula cyclaminifolia (synonym of P. partschiana) and Primula microdonta (synonym of P. sikkimensis). Both species are listed as having been collected in 1894 in their original descriptions, but this is incorrect and should read 1895. The type for P. cyclaminifolia is P00649649 and a small label indicates it was collected on the 18th of March in Lami which corresponds to that given in the book. It is harder to decipher where P. microdonta was found as it is given only as "Mekong, June" but the month seems to relate to when the specimen was received at Paris, not when it was collected as there is a small label on the type herbarium sheet, P04544192 which says 14th September, col (undecipherable). At this date, Prince Henri was climbing out of the Mekong valley to the Salween via a pass to the south of Landjre (28°11'46.76"N 98°49'18.11"E) instead of following the pilgrimage route up the Dokar La.

Primula secundiflora

Read more about these Primula species in the Species Gallery. A recent popular book, Race to Tibet, is loosely the story of Bonvalot and Orléans' journey, with embellishments.

Pam Eveleigh © 2016

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