Sweet Caroline... section Carolinella

Where it began,
I can't begin to knowin'
But then I know it's growing strong

Was in the spring
And spring became the summer
Who'd have believed you'd come along

... Sweet Caroline.*

 

Primula cardioeides in Vietnam

In 1891, Augustine Henry married Caroline Orridge, though their marriage lasted only three years due to Caroline's tragic death from tuberculosis. Henry's job as a Customs officer lead him to Mengzi (modern Honghe) in southeastern Yunnan. By this time he was well established in plant collecting and his collection Henry 10735 from the forests SE of Mengzi was described as Carolinella henryi, named for his late wife. Though it was thought to be a new Genus, Pax later included it within Primula as section Carolinella and the species became Primula henryi. Unfortunately this name had already been used, so it was given the new name "Primula carolinehenryi" by S.O'Brien in the book "In the Footsteps of Augustine Henry". This name has since been corrected according to the International Code of Nomenclature to "Primula carolinehenryae" as it honors a women.

Primula carolinehenryae E00255693
courtesy Royal Botanic Garden Edinburgh

Two additional Henry collections were described from the area around Mengzi under the genus Carolinella: C. cordifolia (now P. partschiana) and C. obovata (now P. rugosa). The distinguishing feature of section Carolinella is the calyptrate capsule (the capsules don't split into 5 valves as most other species do, or by crumbling, but rather have a lid which lifts to expose the seeds). Some authorities recognise subgenus Carolinella which includes this section. The species in the section are distributed in SE Yunnan, S Guizhou, N Guangxi, S Hunan, N Guangdong, and N Vietnam.



P. rugosa, P. kweichouensis, P. wangii from Flora of China

In 2000 the paper "Pollen morphology in Primula sect. Carolinella (Primulaceae) and its taxonomic implications" was published, with SEM images of 7 species. It was found that there was considerable variation in the pollen morphology encompassing all 3 main pollen types (tricolpate, trisyncolpate and polycolpate) of the genus Primula and that this indicated that the group was heterogeneous.

Primula cardioeides pollen
From Pollen morphology in Primula sect. Carolinella (Primulaceae) and its taxonomic implications

In 2010 the paper "Circumscription of Primula subgenus Auganthus (Primulaceae) based on chloroplast DNA sequences" was published. The result of this study was that species assigned to subgenus Carolinella are dispersed among the species of subgenus Auganthus and that as defined, neither subgenus is monophyletic and it is inferred that the calyptrate capsule has evolved multiple times in the genus Primula. Also P. wangii which was initially placed in section Carolinella, but subsequently placed by Richards into section Monocarpicae, has an ambiguous position.

 

In 2015 the paper "Non-monophyly of Primula subgenera Auganthus and Carolinella (Primulaceae) as confirmed by the nuclear DNA sequence variation" was published and it is similar to the 2010 study. It was concluded that the calyptrate capsule has evolved independently at least four times in Primula. P. wangii was found to be close to P. kwangtungensis and P. kweichouensis and so together with P. levicalyx (not sampled) this seems to be a distinct group within the section. In 2014, the species P. hunanensis was described and placed in this group and the following key was presented.

The species presently included in section Carolinella are: P. calyptrata, P. cardioeides, P. carolinehenryae, P. chapaensis, P. hunanensis, P. intanoensis, P. kwangtungensis, P. kweichouensis, P. levicalyx, P. partschiana, P. rugosa, and P. wangii. In future, we can expect that the section will be split to follow the results of genetic study. See the Species Gallery under each of these for more information.



Key (excludes P. hunanensis) from

"Primula calyptrata, a New Species in Section Carolinella (Primulaceae) from Yunnan, China"

* Don't recognise these lyrics? They're from Neil Diamond's "Sweet Caroline"
 

Pam Eveleigh © 2016

 

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Thailand - Pagodas, Beaches, Pad Thai ... and Primulas

Primula siamensis

My holiday experiences in Thailand include golden pagodas, sandy beaches, elephant rides and tasty food. It isn't a place particularly noted for Primulas, but they do grow there. In the northern part of the country, near the popular tourist destination of Chiang Mai, is Doi Chiang Dao, a peak of 2,175m (7,136ft), and the home of the first Thai species described in 1922 as Primula siamensis. This is a really lovely species, growing in limestone crevices, with wide open flowers of violet-blue.


Doi Chiang Dao by Adam Baker

Nearby is Doi Inthanon, the highest mountain in Thailand at 2,565m (8,415ft). The top 700m is the habitat for Primula intanoensis. This is a curious species, part of the little known Carolinella section, with small white flowers, round leaves and calyptrate seed capsules (the capsules don't split into 5 valves as most other species do, but rather have a lid which lifts to expose the seeds). It was mistakenly re-described from the same collections by C.M.Hu as P. larsenii.

Primula caulifera P00649638, Muséum national d’Histoire naturelle, Paris 

A third species is even more unusual. It is Primula caulifera and it is found further to the south at Tunkamang in the Chaiyaphum district at only 800m elevation. This species doesn't look like a Primula at all, having no basal rosette and a long stem with alternate leaves. The small rose colored flowers are borne on whorls (tiers).

Primula forbesii subsp. forbesii

The last species found in Thailand is an extension of the geographical distribution of Primula forbesii subsp. meiantha. This was initially described as Primula meiantha from Burma, but it was found on Doi Chiang Dao in 2002 and 2005 though a subsequent search in 2009 failed to locate this species again. It is similar to P. forbesii subsp. forbesii (familiar to many as a popular houseplant) but with smaller flowers.

If you are going to Thailand and visit these places, I would be interested in images of these species.

Pam Eveleigh © 2016

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The Plant Lover's Guide to Primulas

A new book on Primulas is always welcome! This one is from Jodie Mitchell and Lynne Lawson of the famous Primula nursery, Barnhaven, and it is a Timber Press book that is part of a series produced in association with Kew. It is called "The Plant Lover's Guide to Primulas". My first impression is that $25 US is a very reasonable price for a large format, hardcover book loaded with color images. The authors have a special love of Primula, one that they share through personal reflections at the beginning of the book. They also give a brief history of their nursery, Barnhaven which started in Oregon, but is now located in France. The sections include Designing Gardens with Primulas and Understanding Primulas (with an emphasis on Auricula) before going into details of 100 Primulas for the Garden. This eclectic selection is an interesting mix of species Primula and cultivars, each with a sumptuous image and a description including where to use it in the garden. If you can get through that section without wanting to obtain some of the plants listed, I'd be surprised - I had immediate plant envy! The next section gives necessary details on how to grow and propagate your Primulas and I especially like the section on dividing which is so necessary when growing named cultivars. The book ends with sources of plants and seed, where to see gardens growing Primula and where to get more information about Primulas. If you wanted a good general book on Primulas, look no further. This is the one to buy!

Title: The Plant Lover's Guide to Primulas

Format: Hardcover

Pages: 256 pp.

Book dimensions: 8 x 9 in. (230 x 205 mm.)

Images: 247 color photos

ISBN-10: 1604696451

ISBN-13: 9781604696455

Disclaimer: Pam Received a free copy of this book in return for use of a few images.

Pam Eveleigh © 2016

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Primula specuicola in Utah

Primula specuicola goes by the common name of "Easter Primrose" and that's because it blooms at Easter time. This year (2016) I headed south the week before, making the 17 hour drive to Moab, Utah over two days. I had been there the previous October and had seen a few plants just forming their resting buds, but I was anxious to see this species in bloom.

Primula specuicola growing in an alcove

It was well worth the drive as the plants were in perfect form. Armed with more information than my Fall trip, I was able to see plants at three different locations and observe their habitat and variations. The most striking observation was how limited their habitat is and how they have no ability to establish in other places as they are surrounded by hostile environments. Though this is a member of Section Aleuritia which includes well known species like P. laurentiana, P. farinosa and P. scotica, it is arguably one of the showiest species in this Section, having leaves covered on both sides with white farina, giving them a silver appearance, and having umbels of soft rose colored flowers in the best forms. See the Species Gallery for lots of images.

I made the following video to help you understand the habitat of this remarkable species. Don't forget to change your settings to watch in High Definition. Enjoy!

 

 

Pam Eveleigh © 2016

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