September 2018 ~ Primula World

Primula sachalinensis:

The island Sakhalin lies just north of Japan's Hokkaido and east of mainland Russia. Historically, it has been claimed by both Russia and Japan. For the period of 1905 to 1945, the island was split, with Japan holding the southern portion, and calling it Karafuto. It was during this time, in 1932, that Primula sachalinensis was described¹ by the Japanese botanist Takenoshin Nakai. He cited the type location as "Sachalin: in humidis secus Bakenuma, Hoyankei" and he named M. Gozeki as the collector. Presumably the type sheet resides in TI (Tokoyo) but it isn't online. However a sheet with a part of the type specimen is available at E (Edinburgh) mounted with a second gathering collected 2 weeks later.

Primula sachalinensis at Magunant mud volcano

It is difficult to find "Bakenuma, Hoyankei" on a map since Russia now has control over Sakhalin and Russian names are used. However it is generally accepted that this refers to the Magunant mud volcano, in the Pugachevskie volcano group, at 48°13'41.00"N 142°34'0.00"E. The name "Hoyankei" seems to match "Hoyori village" in the old Japanese Shikuka Subprefecture.

A white form growing at Magunant mud volcano

In 1996, Y. Lee described Primula sachalinensis f. albida, without a type designated. In the same reference, Lee also include an image of a white flowered Primula which he labelled this species, and which was photographed on "백두산" which is Mount Baekdu, now called Paektu located at 42° 0'8.81"N 128° 3'29.81"E on the Korea - China border. As per the discussion following, plants on Mount Paektu are not Primula sachalinensis.

Primula sachalinensis has been considered a variation of Primula farinosa and certainly it is close, but the base of the bracts are gibbose. Regular Primula farinosa does not grow on Sakhalin and Bukhteeva³ noted that these plants growing on freshly ejected mud substrate differed from normal Primula farinosa to such an extent that the classification of Primula sachalinensis as a distinct species, endemic to Sakhalin, was justified. Kovtonyuk⁴ included Primula sachalinensis in a genetic study and confirmed it was distinct and more closely related to Primula mistassinica, Primula modesta and Primula incana.

¹ Original description on page 61 within the PDF of Bot. Mag. (Tokyo) 1932, xlvi.
² Original description Fl. Korea (Lee) 1159, without type. 1996.
³ Bukhteeva, A.V., Primula sachalinensis Nakai, the Primula species of the Maguntan volcano, Bot. Zh., 1960, vol. 45, no. 5, pp 746-748.
⁴ Kovtonyuk, N.K. and Goncharov, A.A., Phylogenetic relationships in the Genus Primula L. (Primulaceae) inferred from the ITS region sequences of nuclear rDNA, Russ. J. Genet., 2009, vol. 45, no. 6, pp. 663-670.

When in Nepal in the spring of 2018, I had a chance to study Primula gracilipes in detail. This species blooms early - I saw it in April. It belongs in section Petiolares and is closely related to several other species which have a similar loose cushion habit and dimorphic leaves (two different leaf shapes are produced depending on the time of year). One of the key features to see when identifying this group of species is the flower scape (or lack of). I used a technique where leaves were removed from one side of the plant to observe this and those leaves were then laid out for imaging. What follows are some of the images I took to document this species. Click on the images for larger sized versions.

An example plant is removed from the soil and measured.

The plant is shown upside down to show the root structure
and the absence of basal bud scales

Leaves removed from one side on the plant, with petioles intact. The leaves are arranged in order of their removal,
outer leaves (left) and inner leaves (right). The leaves are turned over, keeping their placement to show the underside.

Now you can see the internal structure of the plant.

You can clearly see that there is no scape, but that each pedicle comes from the base of the plant. You can see the bracts which are broad at the base and taper to a point.

P. gracilipes produces two different leaf shapes. The form with the long petioles are produced late season so I searched the base of several plants to find last years old leaves.

At a lower elevation I found plants which had bloomed earlier and were now producing this second leaf shape.

An example of farina on new leaves (right)

The flowers are shown from the side to see variation in the calyx. The flower on the right is a "thrum", and you can see the bulge in the flower tube where the anthers are located.