Chine: Yunnan: Beyendjing, en forets à 2300-2800m. Sud-ouest du Sichuan (Liangshan).

Holotype C : Siméon Ten 1392: 25 sept 1919, Chine, Yunnan, Pel Tsao-Lin.

BWJ8022

DHCG97057

Bibliographie personnelle :

G/A0063. Clifton Richard, Geranium christensenianum, Geraniaceae group news 77, . Spring 2000 .

G/F0048: Yeo, P. F. 1992. A revision of Geranium L. in south-west China. Edinburgh J. Bot. 49: 123-211.

G/A0095. Clifton Richard, Geranium christensenianum, Geraniaceae group news 110, . 2008, p. 16.

G/A0096. Tim Upson, Geranium christensenianum, Curtis botanical magazine, . 2006-vol.23(1), p. 547.

G/A0111: David Victor, Geranium christensenianum, Geraniaceae group news 112, winter 2008-09.

Description horticole :

Heronswood (USA), 2003: Eric's collection from Longzhou Shan in Sichuan, and a decidedly interesting introduction perhaps not offered before in western horticulture. Closely resembling a very beautiful, white-flowered, red-veined form of Geranium procurrens, with prostrate stems spreading to 6 ft. by the end of the summer, and out or down (as opposed to down and out) facing flowers throughout the late summer and autumn. I delighted in observing this in the wilds near Huili, Sichuan Province, in the autumn of 2000. Geraniaceae W. China.

BWJ8022 Crug Farm Plants (UK) 2003: A Chinese species which I collected with Dan Hinkley in Southern Sichuan. Found growing on steep sunny banks where the shortly trailing habit of this G. lambertii-like species displayed its white dark-violet veined flowers July-Oct, Sun to part-shade moist well drained soil.

Description botanique :

Perennials. Rootstock 5-6 mm in diam., not tuberculate, with many fibrous roots. Stem 48-100 cm tall, trailing, rooting at nodes, with 0.3-1.3 mm patent nonglandular trichomes and 0.5-1.1 mm patent glandular trichomes. Stipules lanceolate, distinct. Leaves opposite; petiole with 0.2-1 mm patent nonglandular trichomes and 0.2-1.4 mm patent glandular trichomes; leaf blade 3.9-5.3 cm, palmately cleft, ratio of main sinus/middle segment length = 0.72-0.78, pilose with appressed nonglandular trichomes and ± patent glandular trichomes; segments 3(or 5), rhombic, 8.6-10.7 mm wide at base, 5-13-lobed in distal half, ratio of second sinus/middle segment length = 0.15-0.21. Cymules solitary, 2-flowered; peduncle 2.1-15.3 cm. Pedicel 0.8-1.7 cm, with 0.2-0.6 mm patent nonglandular trichomes and 0.3-1.2 mm patent glandular trichomes; bracteoles lanceolate. Sepals 0.8-1.2 cm, mucro 1.6-2.7 mm, ratio of mucro/sepal length = 0.18-0.22, outside with 0.2-0.8 mm antrorse to patent nonglandular trichomes and 0.5-1.6 mm ± patent glandular trichomes, inside glabrous. Petals whitish with fine dark purple veins, 1.2-1.4(-1.6) cm, erect to patent, outside basally with trichomes, margin basally ciliate, apex rounded. Staminal filaments blackish except base, lanceolate, abaxially densely covered with 0.2-0.8 mm trichomes but glabrous toward tip; anthers black, 2.1-2.5 mm. Nectaries 5, hemispheric, abaxially glabrous, apex with a tuft of trichomes. Stigma blackish. Fruit ca. 3.2 cm, erect when immature; mericarps smooth, with a basal callus, with 0.3-1 mm ± patent nonglandular trichomes and 0.6-1.5 mm patent glandular trichomes; rostrum 2.1-2.2 cm, with a 4-5 mm narrowed apex; stigmatic remains 5.9-6.2 mm. Seeds unknown. Fl. Jul-Aug, fr. Sep-Oct. Forests, scrub, meadows; 2300-2800 m. SW Sichuan (Liangshan), NE Yunnan.

G/A0096. Tim Upson, Geranium christensenianum, Curtis botanical magazine, . 2006-vol.23(1), p. 547. Summary. The discovery, taxonomic history and affinities of Geranium christensenianum Handel-Mazzetti are described. Its recent introduction and cultivation quirements are discussed. Cambridge University Botanic Garden is well known for its collection of hardy geraniums built up by Dr Peter Yeo, formerly Taxonomist in the Garden. It provided research material for his landmark Hardy Geraniums first published in 1985 with a new edition in 2001 (Yeo 1985 & Yeo 2001), and many of the accessions mentioned in these books are still in cultivation at Cambridge today. The collection is registered with the National Council for the Conservation of Plants and Gardens (NCCPG) and was given Scientific Status in 1999; it continues to provide a valuable source of reference. Most species of hardy Geranium have already been featured in Curtis’s Botanical Magazine, and one of the few yet to be treated is the Chinese species G. christensenianum which has remained relatively unknown though first described in 1933. It was only introduced into cultivation in 1997, from Longzhou Shan, Sichuan by Eric Hammond, formerly Head Propagator at Heronswood Nursery, during a collecting trip undertaken in conjunction with Kunming University. Material cultivated by Dan Hinkley at Heronswood was sent in 1999 to David Victor, registrar for Geranium and Erodium cultivars in England (Yeo 2001) and it is from this that our plate was prepared. These plants are now in the collection at Cambridge. It is grown in a few other specialist collections and is listed as available from only one nursery in the RHS Plant Finder (Lord et al. 2005) from what appears to be a second, more recent introduction. This species was described and named by the Austrian botanist and explorer Heinrich Handel-Mazzetti (1882-1940). In 1913 Handel-Mazzetti joined the General Secretary of the Austro-Hungarian Dendrological Society, Camillo Schneider, on an expedition o western China, prompted by the exciting finds of the plant hunter George Forrest. Stranded by the outbreak of the First World War, Handel-Mazzetti travelled extensively in China and on his return to Austria in 1919, worked in Vienna at both the University Botanical Institute (WU) and then at the Natural History Museum (W) becoming Keeper of the Botany Department. In the 1930s he found himself free from official duties, and able to devote all his energies to the vast collections he had made in China (Winstanley 1996). He published his findings in Symbolae Sinicae which also included descriptions of plants collected by others. The specimens from which Handel-Mazzetti described G. christensenianum were originally collected by the Chinese missionary Simeon Ten in 1917 from Beyendjing (Peyentsin) in Yunnan. Handel-Mazzetti (1937) explains that he received this material for determination from the Botanical Museum, University of Copenhagen, where it was originally deposited, and the epithet he chose honoured the Danish pteridologist, Carl F.A. Christensen (1872–1942), who was responsible for sending him the specimens. Geranium christensenianum belongs to the Sylvaticum section, section Geranium (subgenus Geranium), which includes many of our most popular garden geraniums (Yeo 2001). Handel-Mazzetti (1933) placed this species in section Striata Knuth and noted its close affinities with G. wallichianum, differing in the presence of glandular stem hairs and fused stipules. Yeo (2001) did not follow the categories of subsection and series in section Geranium, noting that with over 250 species he could not see how smaller groups could be defined clearly. Instead he recognised informally named groups of what he believed to be closely related species, placing G. christensenianum in his Wallichianum group. The Wallichianum group consists of six Himalayan species (G. wallichianum D. Don, G. lambertii Sweet, G. procurrens Yeo, G. kishtvariense Knuth, G. rubifolium Lindl. and G. swatense Scho¨nb.-Tem.) plus this species from China. The group is typified by its scrambling and trailing stems, with the basal rosettes scarcely developed, leaves divided into 3 or 5 lobes to a depth of three quarters of the leaf lamina. The petals bear hairs across the front surface at the base, the style is very short, about two thirds as long as the sepals and the stigmas to 4 mm or more long (Yeo 2001). Geranium christensenianum is most readily distinguished from its relatives by its white flowers with purplish red veins and comparatively large flowers, up to 37 mm wide. The white background colour of the flowers recalls G. lambertii which can be white or pale pink with a crimson stain at the base. The scrambling or trailing stems that can reach over a metre in length and root easily at nodes are distinctive, and in this respect it resembles G. procurrens. CULTIVATION. In common with other members of the Wallichianum group the trailing stems make it a good subject for the front of borders, woodland and wild gardens, where its stems can trail freely through other plants. It grows best in partial shade (Geraniaceae Group News, Spring 2000) in a humus rich soil and benefits from mulching with organic matter. It has so far proved hardy in cultivation in the British Isles and makes an attractive subject for late summer and autumn. The stems root readily at the nodes under suitable conditions making it easy to propagate and seed germinates readily (David Victor pers. com.).

Notes :

Collecteurs: La premiere réintroduction de ce geranium est due à Eric Hammond sous le n°EDHCH 97057. Plante collectée en Chine dans les années 1990 et dans la région de Longzhou Shan au Sichuan. Eric Hammond est le responsable de la multiplication de la pépinière américaine Heronswood (Orégon). Lors de cette exploration, Eric était acompagné du Pr. Weibang Sun du jardin botanique de Kunming. BWJ8022: Southern Sichuan.