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FORMOSANUM N. E. Brown, 1885

Synonyms :

Sedum loochoense  Makino & Kuroiwa (1900)

Sedum mariae Hamet  (1910)

Sedum taiwanianum  auct. (1972)


Distribution : Taiwan, Japan (Oshima Island, Ryukyu, Kyushu), northern Philippines (Batan Islands), probably southern Korea; rocks at the shore, rarely inland.



Description (by 't Hart & Bleij in IHSP, 2003) :


Annual tufted herbs with erect or arcuate, di-or trichotomously branched, densely leafy, rather stout stems, to (15-) 20 cm tall.


Leaves alternate, sometimes whorled, spatulate to obovate, rounded to obtuse, 10 - 20 x 8 - 12 mm.


Inflorescences rather large many-flowered cymes, bracts leaf-like.


FIowers 5-merous, sessile, sepals basally free, shortly spurred, unequal, linear-lanceolate to spatulate-subovate, rounded to obtuse, 3,5 - 5 mm, petals semi-oblong, broadly submucronate, yellow, 5 - 7 mm, anthers yellow.


Cytology : 2n = 64, 66.


Note :

1. Close to S. alfredii and included under that species by Fu & Pu (1984). It is hapaxanth like S. alfredii and sometimes perennating (Ohba 1982e: 559).

2. Takuro Ito et al., published the ssp. miyakojimense in Phytotaxa 148: 51-70, 2020.



Ray Stephenson (Sedum, Cultivated Stonecrops, 1994, p 159)

 Common name : Hama-mannengusa


Upon first growing this species, I was amazed at the stature plants attained. Bases of stems developed a girth of nearly 2 cm (0,8 in), and annual plants, resembling little bonsai trees, exceded 25 cm (10 in) in height . Well-spaced, very blunt, thin, bright green, obovate-spatulate leaves are alternate or sometimes opposite. The large cymes of flowers are not particularly bright, but carry a lot of sessile flowers.


Habitat : Ryukyu Islands, China, Philippines, and Taiwan are the homes of this species, mostly along seashores.

Main points of distinction : The form in cultivation bears little resemblance to other yellow-flowered Far Eastern sedums. It is a stout, upright annual or biennial. Stems are forked, and eventually spread. Flowers have slightly spurred, spreading, leaf like sepals. Carpels are only slightly divergent in fruit.

Variation : Drawings of plants collected from habitat indicate some plants can be quite feeble. Plants have been reported that geographically and vegetatively are midway between Sedum nagasakianum and the species.

Horticulture : It is said that this species can be persuaded to act as a perennial, as it often does in the wild, but so far I have not succeeded. I was disappointed when rooted cuttings flowered at exactly the same time as the parent plants, neither producing sterile shoots.

Photo Ray Stephenson

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