Origin and Habitat: Native to Tropical Afric ( The Democratic Republic of Congo, Kenya, Tanzania, Uganda, Zaire, Burundi, Rwanda and Mozambique)
Habitat and ecology: Dorstenia hildebrandtiiSN|29198]]SN|29198]] is found on coral and granitic limestone outcrops and in open forest, woodland, bushland, thicket, dry and moist montane forest and lowland evergreen forest. This species is very widespread and does not appear to be under threat across its range.
Synonyms:
See all synonyms of Dorstenia hildebrandtii
Description: Dorstenia hildebrandtiiSN|29198]]SN|29198]] is an unusual rhizomatous or tuberous succulents plant sought in specialist collections of caudiciforms. It has a fleshy, reddish brown, shiny swollen bulbous base (caudex), whose top elongates into a simple or branched, shoot crowned by leaves. Leaves almost stalkless. D. hildebrandtii seems to be quite variable and there are various morphological or geographic forms/subspecies.
Caudex (base of the stem): Above-ground, bulbous, more or less swollen, globose to pear-shaped, juicy, up to 4(-5) cm in diameter.
Stem (leafy part): Ascending to erect, branched or unbranched (the branches often arrested, with minute leaves), fleshy to sometimes thickly succulent, 15-70 cm long, about (1-)5-7(-10) mm thick above, glassy, transluscent, reddish-flecked very minutely puberulous below the leaves, otherwise glabrous. Scars of leaves, stipules and inflorescences often conspicuous and prominent.
Leaves: Sessile or almost stalkless, spirally arranged, fleshy, oblong to elliptic, lanceolate, oblanceolate or linear, acute, narrowing cuneately to the base, (0.5-)1-12(-20) cm long, 3-16 mm wide, green. Margin irregularly coarsely crenate to dentate toothed sometimes subentire, revolute when dry. Superior surface glabrous and smooth, the inferior surface puberulous to glabrous, lateral nerves not prominent. Stipules subulate, 1-2 mm long. Chartaceous to papyraceous when dry.
Inflorescence: Solitary or in pairs near stem apexes, round almost starry or narrowly elliptic to 3–6-angular in outline. Peduncle (2-)5-10(-25) mm long, sometimes recurved, minutely and densely downy. Receptacle green to dark purple 4-12 mm across, suborbicular to funnel-shaped, appendages (2-)5–7(-12), triangular, linear-tapering, to band-shaped or filiform, very unequal, (2-)4-20(-25) mm long, with intervening unequal semicircular to triangular teeth (up to 2 mm long), forming a crenate to dentate rim, minutely downy.
Female flowers: Numerous, scattered; style bifid. Endocarp body ovate to tetrahedral, about 1-1.5 mm long, verruculose except on the ventral aspect.
Male flowers: Crowded; perianth lobes (2)3(4); stamens (2)3(4).
Fruit: Ovoid, warty.
Blooming season: Spring to late Autumn.
Subspecies, varieties, forms and cultivars of plants belonging to the Dorstenia hildebrandtii group
- Dorstenia hildebrandtii Engl.: has a fleshy, reddish brown, swollen bulbous base (caudex) with a simple or branched shoot to 70 cm tall crowned by leaves. Distribution: grows in dry habitats in Congo, Kenya, Tanzania, Uganda, Zaire, Burundi, Rwanda and Mozambique.
Dorstenia hildebrandtii f. crispa- Dorstenia hildebrandtii f. rubra
- Dorstenia hildebrandtii var. schlechteri (Engl.) Hijman: up to 70 cm tall; stems slender, the base not swollen nor tuber-like, but slender and creeping, stems often unbranched. Distribution: Grows in mesic habitats in Eeastern Tanzania and Kenya
Bibliography: Major references and further lectures
1) J. Hutchinson and A. B. Rendle “Flora of Tropical Africa” Vol 6 Part 2, page 17 1916
2) C. C. Berg “Flora Zambesiaca” Vol 9 Part 6, page 13 1991
3) Urs Eggli “Illustrated Handbook of Succulent Plants: Dicotyledons” Springer Science & Business Media, 2002
4) Werner Rauh “The Wonderful World of Succulents: Cultivation and Description of Selected Succulent Plants Other Than Cacti” Smithsonian Institution Press, 1984
5) Stuart Max Walters “The European Garden Flora: Dicotyledons (Part I)” Cambridge University Press, 1989
6) Jacobsen “Lexicon of succulent plants” Littlehampton Book Services Ltd. 1974
7) Edgar Lamb, Brian Lamb “The Illustrated Reference on Cacti & Other Succulents” Volume 5 Blandford Press, 1978
8) Alfred Byrd Graf “Exotica, series 4 international: pictorial cyclopedia of exotic plants from tropical and near-tropic regions” Roehrs Co. Publishers, 1982
9) IUCN SSC East African Plants Red List Authority 2013. "Dorstenia hildebrandtii." The IUCN Red List of Threatened Species. Version 2014.2. <www.iucnredlist.org>. Downloaded on 27 October 2014
10) Berg, Cornelis C. "Moreae, Artocarpeae, and Dorstenia (Moraceae), with Introductions to the Family and Ficus and with Additions and Corrections to Flora Neotropica Monograph 7". Flora Neotropica 83: 1–346. 2001
Cultivation and Propagation: Beloved by collectors, Dorstenia hildebrandtiiSN|29198]]SN|29198]] is an excellent pot plant and it should make an interesting addition to a collection.
Growth rate: It grows well, though very slowly, but it possible to increase the speed of growth to some extent by providing adequate amount of water, warmth, and fertilizer during the active growing season, but it’s susceptible to rotting if too wet.
Exposure: It needs light shade, but the caudex should be in the shade, while the leaves prefer some sun. Avoid direct blasting sun in summer. Bright light if grown indoors.
Soil: It needs a very porous potting medium (add pumice, vulcanite, and perlite). It does better in a rather acidic soil.
Waterings: During the growing season, the plants appreciate a fair amount of water but allow the soil to dry slightly between watering, making sure that they never dry out completely, but keep dry during the winter after the leaves have died back. It rot easily and do NOT like a lot of water when it has no leaves. They have to be kept in a rather high air humidity.
Fertilizer: They are fertilized once during the growing season with a balanced fertilizer diluted to ½ the strength recommended on the label.
Frost tolerance: Due to its African origin keep warm in winter, the minimum safe average temperature is 15°C, although it can go lower for short periods. It can be grown outdoors in frost-free climates, need anyway to kept above 10°C and dry in winter. It is very prone to rot in cool, wet conditions. USDA Zone 12, but does very well in containers.
Maintenance: Repot every two years. It like pots with generous drain holes.
Propagation: Dorstenias are usually propagated by seed. Seed germinate readily at 21° C. They can also be propagated by cuttings.
Warning: As with all Adenias, all parts of this plant are very toxic, and they should be handled with caution, particularly when pruning.
