This is a revised version of the article that originally appeared in the June 1998 issue of The Baltimore Areole, newsletter of the Cactus & Succulent Society of Maryland.
FOCKEA, CIBIRHIZA AND PETOPENTIA
by Steve Jankalski
The genus Fockea Endlicher is a well known and widespread genus in southern Africa, despite this, within the genus, the species limits have long beeen poorly understood. Grace Doreen Court (1987) provided a synopsis of the genus and discussed the botanical history of each species. She recognizes six species as valid. The recent treatment of the genus by Meve in Albers & Meve (2002) concurs with the one presented here. The naming of Fockea species by various British, French, Swiss, German and South African botanists has resulted in all the species being named more than once. The invalid superfluous names are often seen on plants in the horticultural trade.
The flowers of Fockea species are all remarkably similar. The five corolla lobes are spreading, narrow with revolute margins and rather dull greenish to brownish in color. The prominent corona is pale yellow to white with a prominently fringed crown. The lobes of the fringe may be quite long and showy. The flowers are sweetly scented.
The widely grown Fockea capensis Endlicher has distinctive wavy and crisped margined leaves. It is widely known from a single plant that has been growing at the Schönbrunn botanical garden near Vienna, Austria since 1788 and it was long believed to be the only plant of the species in existence. South African botanist, Rudolph Marloth dispelled that myth when, in 1906, he found it to be fairly common in the Prince Albert district of South Africa. It is still widely known as the synonymous, F.crispa (Jacquin) K.Schumann which is an invalid name, as it is based on an illegitimate homonym.
Fockea sinuata (E.Meyer) Druce is the miniature of the genus with short, non-twining and narrow crisped leaves. It is the species most suited to pot culture but ironically is rarely offered in catalogs.
Fockea edulis (Thunberg) K.Schumann, F.angustifolia K.Schumann and F.comaru (E.Meyer) N.E. Brown form a closely allied species complex of which F.angustifolia K.Schumann (sensu lato) is the central taxon and consequently extremely variable with many synonyms. The three species are distinguished on the basis of leaf shape and pubescence by Court (1987). Of the three species, F.edulis (Thunberg) K.Schumann forms the largest caudex, which may become massive with age.
Fockea angustifolia K.Schumann, known as "Kambroo" in Zimbabwe, is extremely variable in flower size and leaf shape and this has led to an extensive synonymy. Flowers may have corolla lobes ranging widely in length from 2 to 30 mm. long according to Court (1987). The populations from Natal have the smallest flowers and those from Namibia have the largest, connected by populations with a full range of intermediate sized flowers. Those large flowered populations from the northern part of its range in Botswana and Zimbabwe have an elaborate collar fringing the corolla lobes, gradually disappearing as flower size diminishes in populations southward. The leaves may be glaucous to green, broad and rounded to narrow elliptic and with margins wavy or not, in a variety of combinations.
The combination Fockea angustifolia var. volkii mentioned by Court (1987) is an unpublished manuscript name proposed by H.Huber which appeared on an herbarium sheet. The specimen upon which the name appeared (Volk 911c) was annotated as Fockea comaru (E.Meyer) N.E. Brown by Court (1987). I am indebted to Craig Hilton-Taylor for confirming this information.
Fockea multiflora K.Schumann, the "Vegetable Python", is the giant in the genus. It will form an imposing specimen for those lovers of caudiciform plants. In the wild, the stems can grow up to 10 meters in height, wrapping around savanna trees as a liana.
Plants in cultivation as Fockea tugelensis have proven not to be that species but are actually another caudiciforn not at all closely related and correctly named Petopentia natalensis (Schlechter) Bullock. The plant illustrated in Rowley (1987) as the former is actually this plant. The plant has also been grown under the invalid name Fockea natalensis. The monotypic genus Petopentia is native to Natal and Transkei in South Africa, growing mostly along the coast, and is easily distinguished from Fockea even when not in flower. The true affinities of the genus are with Raphionacme and its allies in subfamily Periplocoideae. This plant is a vine with a tuberous rootstock that is often epigeal (above ground) and constricted into segments. The leaves are smooth and shiny, to 13 cm. long, broadly ovate with a rounded to cordate base and a prominent purple midrib and petiole. The flowers are to 3 cm. in diameter, with green to brownish purple corolla lobes with a single erect filiform corona appendage at the base. The cone shaped gynoceum is exserted above the corolla. As is typical for subfamily Periplocoideae, the pollen is granular and not in pollinia. Venter & Verhoeven (2001) have transferred the species to the previously monotypic Madagascan genus Ischnolepis Jumelle & Perrier but their doing so has been disputed by Albers & Meve (2002). The latter authors keep the two separate and even go as far as to place the two monotypic genera in different tribes in subfamily Periplocoideae. The two species are easily distinguishable, even by vegetative characters and are recognized as belonging to allied but separate monotypic genera here.
The Madagascar species Ischnolepis graminifolia (Costanitn & Gallaud) Klackenberg is a tuberous rooted dwarf shrub with narrow leaves in whorls of three and yellowish flowers in subterminal cymes. Ischnolepis tuberosa Jumelle & Perrier is a synonym. The species superficially resembles Euphorbia hedyotoides N.E. Brown in its growth form and very different from South African Petopentia natalensis (Schlechter) Bullock which is a vine.
Cibirhiza dhofarensis is the name Peter Bruyns gave to an anomalous plant collected in the Dhofar Province of the Sultanate of Oman on the Arabian peninsula. The generic name alludes to the edible tuberous root of this species. The flowers are much less specialized than those of Fockea, superficially resembling those of a Stapelia, but smaller. A second species, Cibirhiza albersiana, was recently described by Kunze, Meve & Liede (1994), appropriately named in honor of Dr. Focke Albers, a prolific student on Asclepiadaceae. The latter was based on several African specimens from Zambia and Tanzania in the Kew herbarium that had long remained unidentified. Both species have rotate flowers in dense umbelliform clusters in the leaf axils. The flowers are only 10-14 mm. in diameter and are greenish yellow, densely red spotted on the inner surface. The corona is reddish brown. The rootstock is a brown, woody, elongated, turnip-shaped tuber that may exceed 30 cm. in diameter at maturity. The stems are scrambling to twining with paired broad leaves. Remarkably, the two species differ only in the shape of the leaf blade base and number of horns on the corona lobes.
All of the species of Fockea are found in cultivation. They are relatively undemanding in culture but need a winter dormant period. Propagation is best by seed. The flowers are self sterile and two plants are needed to set seed. As in all Asclepiads, artificial pollination is difficult. Hybrids are not known. Stem cuttings usually fail to root. Cibirhiza dhofarensis has recently found its way in cultivation, so keep an eye open for it.
The affinities of Fockea and Cibirhiza have long been problematic. They have in the past been considered aberrant genera in the tribe Marsdenieae but are at once easily distinguished from that tribe and the allied tribe Stapelieae (including tribe Ceropegieae) by having the paired pollinia sessile and not attached to the corpusculum by caudicles. For this reason, Kunze, Meve & Liede (1994) found it necessary to name a new tribe for the two genera.
Asclepiadaceae tribe Fockeeae H.Kunze, Meve & Liede, Taxon 43 (3): 373 (1994)
Plants tuberous caudiciforms with a milky sap. Stems usually twining. Paired pollinia attached directly to the corpusculum, caudicles absent.
Cibirhiza Bruyns, Notes Royal Bot. Gard. Edinb. 45 (1): 51 (1988)
Corolla shallow campanulate at base, lobes short and broad; interstaminal (outer) corona much shorter than the staminal one; staminal (inner) corona with filiform appendages; anther appendages incurved and small.
A. Leaf blade with a prominently cordate base; flowers with staminal (inner) corona lobes one horned.
Cibirhiza dhofarensis Bruyns, Notes Royal Bot. Gard. Edinb. 45 (1): 51-54, fig. 1 (1988); Miller & Morris, Plants of Dhofar 60-61, illus. (1988) [Oman]
AA. Leaf blade with an acuminate to subcordate base; flowers with staminal (inner) corona lobes three horned.
Cibirhiza albersiana H.Kunze, Meve & Liede, Taxon 43 (3): 368-371, figs 1-9 (1994) [Tanzania, Zambia]
Fockea Endlicher, Iconographia Genera Plantarum t.91 (1839)
syn. Chymocormis Harvey in Hooker's Journ. Bot. (London) 1: 23 (1842)
Corolla tubular at base, lobes lanceolate; interstaminal (outer) corona tubular and longer than the staminal one, fimbriate apically; staminal (inner) corona as appendages on inner surface of the outer corona; anther appendages erect and large.
(Included below are listed the plant introduction numbers of the International Succulent Institute.)
A. Plants tuberous rooted perennials, stems slender and deciduous.
B. Leaves with crisped (wavy and curled upward) margins. (C.)
C. Leaves narrow lanceolate; stems erect.
Fockea sinuata (E.Meyer) Druce, Rep. Bot. Exch. Cl. Brit. Isles 1916: 623 (1917) [South Africa, Namibia]
syn. Brachystelma sinuatum E.Meyer, Comm. Pl. Afr. Austr. 195 (1836)
___Fockea undulata N.E. Brown, Kew Bulletin 1895: 260 (1895)
illustration: Rowley, Caud. & Pachy. Succ. 70, pl. 7.10 (1987)
CC. Leaves elliptical; stems twining.
Fockea capensis Endlicher, Iconogr. Gen. Plant. t.91 (1839), Nov. Stirp. Dec. 17 (1839) [South Africa]
syn. Fockea edulis var. capensis (Endlicher) Rowley, Asklepios 75: 17 (1998)
___Cynanchum crispum Jacquin, Fragmenta Botanica 31, t.34 (1800) not Thunberg (1794)
___Fockea crispa (Jacquin) K.Schumann in Engler & Prantl, Nat. Pflanzenfam. 4 (2): 296 (1895) nom. Illegit.
illustrations: Rowley, Caud. & Pachy. Succ. 64-67, pl. 7.2-7.4 (1987) as F.crispa (Jacq.) K.Sch.
ISI 371 M.Malherbe s.n., Barrydale District, S.Africa (Cact. & Succ. Journ. Amer. 33 (2): 63 (1961)) as F.crispa (Jacquin) K.Schumann
ISI 1757 Gil Tegelberg, from seeds collected from ISI 371 (Cact. & Succ. Journ. Amer. 59 (2): 73 (1987)) as F.crispa (Jacquin) K.Schumann
BB. Leaves with straight to wavy or revolute margins; stems twining. (D.)
D. Leaves lanceolate to elliptical with straight to wavy margins. (E.)
E. Leaves glabrous, smooth and shiny.
Fockea edulis (Thunberg) K.Schumann in Engler & Prantl, Nat. Pflanzenfam. 4 (2): 296 (1895) [South Africa]
syn. Pergularia edulis Thunberg, Prodr. Pl. Cap. 38 (1794)
___Echites edulis Thunberg, Gen. Echit. Observ. 5, tab. (1819)
___Chymocormis edulis (Thunberg) Harvey, Journ. Bot. (London) 1: 23 (1842)
___ Brachystelma macrorrhizum E.Meyer, Comm. Pl. Afr. Austr. 197 (1836)
___Fockea glabra Decaisne in De Candolle, Prodromus 8: 545 (1844)
___Fockea cylindrica R.A. Dyer, Kew Bulletin 1933: 459 (1933), R.A. Dyer in Hooker's Icon. Pl. 33: t.3221 (1933)
illustration: Rowley, Caud. & Pachy. Succ. 69, pl. 7.8 (1987)
ISI 543 (collector not cited) Carlisle Bridge, Bedford Dist., Cape Prov., S.Africa (Cact. & Succ. Journ. Amer. 40 (2): 85 (1968))
ISI 701 (collector not cited) Coombs Valley, S.Africa (Cact. & Succ. Journ. Amer. 43 (2): 93 (1971)) as F.cylindrica R.A. Dyer
EE. Leaves pubescent, at least on upper surface.
Fockea angustifolia K.Schumann, Bot. Jahrb. 17: 146 (1893) [South Africa, Namibia, Botswana, Zimbabwe, Zambia]
syn. Fockea sessiliflora Schlechter, Bot. Jahrb. 20 Beibl. 51: 44 (1895)
___ Fockea lugardii N.E. Brown in T.Dyer, Fl. Trop. Afr. 4 (1): 429 (1904)
___ Fockea dammarana Schlechter, Bot. Jahrb. 38: 56 (1905)
___ Fockea tugelensis N.E. Brown in T.Dyer, Fl. Cap. 4 (1): 778 (1908)
___ Fockea milbraedii Schlechter, Wiss. Ergbn. Deutsch. Zentr.-Afr.-Exped. 1907-8 (2): 545 (1913)
___ Fockea monroi S.Moore, Journ. Bot. (London) 52: 149 (1914), 57: 213 (1919)
___ Cynanchum omissum Bullock, Kew Bulletin 10: 623-624 (1955)
___ Brachystelma circinatum sensu Marloth, Bot. Jahrb. 10: 244 (1889) not E.Meyer (1836)
illustrations: Rowley, Caud. & Pachy. Succ. 69, pl. 7.7 (1987)
DD. Leaves linear with revolute margins, pubescent on upper surface.
Fockea comaru (E.Meyer) N.E. Brown in T.Dyer, Fl. Cap. 4 (1): 781 (1908) [South Africa]
syn. Brachystelma comaru E.Meyer, Comm. Pl. Afr. Austr. 195 (1836)
___Fockea gracilis R.A. Dyer, Kew Bulletin 1933: 459 (1933), R.A. Dyer in Hooker's Icon. Pl. 33: t.3222 (1933)
___Fockea angustifolia var. volkii H.Huber, mss. (Volk 911c (BR))
illustration: Rowley, Caud. & Pachy. Succ. 70, pl. 7.11 (1987)
AA. Plants large, caudiciform lianas; stems twining and persistent.
Fockea multiflora K.Schumann, Bot. Jahrb. 17: 145 (1893) [Kenya, Tanzania, Zambia, Zimbabwe, Mozambique, Botswana, Namibia, Angola]
syn. Fockea schinzii N.E. Brown, Kew Bulletin 1895: 259 (1895)
illustrations: Rowley, Caud. & Pachy. Succ. 68, pl. 7.5-7.6 (1987)
ISI 1758 M.Kimberley s.n., Hwange Dist., Zimbabwe (Cact. & Succ. Journ. Amer. 59 (2): 73 (1987))
Asclepiadaceae subfamily Periplocoideae G.Don (1838)
syn. Periplocaceae Schlechter (1905)
Both Petopentia Bullock and Ischnolepis Jumelle& Perrier are currently placed in tribe Periploceae Bartling (1830) according to the classification of Venter & Verhoeven (1997, 2001).
A. Plants vines with paired petiolate broadly oblong leaves; flowers with green to brownish purple corolla lobes, in axillary cymes; the five filiform corona lobes much longer than the staminal column.
Petopentia Bullock, Kew Bulletin 10: 362 (1954); Venter, Verhoeven & Kotze, S. Afr. Journ. Botany 56 (3): 393-398 (1990)
Petopentia natalensis (Schlechter) Bullock, Kew Bulletin 10: 362 (1954) [South Africa (Natal, Transkei)]
syn. Pentopetia natalensis Schlechter, Journal of Botany (London) 32: 257 (1894), 34: 315 (1896)
___Tacazzea natalensis (Schlechter) N.E. Brown in T.Dyer, Fl. Trop. Afr. 4 (1): 514 (1907)
___Ischnolepis natalensis (Schlechter) Venter, Ann. Missouri Bot. Gard. 88 (4): 565 (2001)
___Fockea tugelensis hort. not N.E. Brown (1908)
___Fockea natalensis hort. (nom. illegit. ICBN art. 29.1)
illustration: Rowley, Caud. & Pachy. Succ. 18, pl.3.2; 70, pl.7.9 (1987) as Fockea tugelensis N.E. Br.; Van Uijen, Succulenta 70 (5): 99, fig. on 100 (1991) as Fockea tugelensis N.E. Br.; Knippels, Succulenta 72 (6): 262, fig. (1993) as Fockea natalensis.
AA. Plants dwarf shrubs with linear leaves ternate (in whorls of three); flowers with yellowish green corolla lobes, in subterminal cymes; the five filiform corona lobes equalling the staminal column in length.
Ischnolepis Jumelle& Perrier, Rev. Gen. Bot. 21: 53 (1909); Klackenberg, Candollea 54 (2): 332- 335 (1999)
Ischnolepis graminifolia (Costantin & Gallaud) Klackenberg, Candollea 54 (2): 332, fig. 32 (1999) [Madagascar]
syn. Pentopetia graminifolia Costantin & Gallaud, Bull. Mus. Hist. Nat. (Paris) 13: 443 (1907)
___ Ischnolepis tuberosa Jumelle & Perrier, Rev. Gen. Bot. 21: 53 (1909)
Bruyns, P. (1988) STUDIES IN THE FLORA OF ARABIA XXI: CIBIRHIZA, A NEW GENUS OF ASCLEPIADACEAE FROM OMAN. Notes Royal Bot. Gard. Edinb. 45 (1): 51-54, 1 fig.
Court, G.D. (1987) FOCKEA ENDL. - AN AFRICAN GENUS. Asklepios 40: 69-74, 7 figs.
Dyer, R.A. (1933) FOCKEA CYLINDRICA. Hooker's Icones Plantarum 33: tab. 3221.
Dyer, R.A. (1933) FOCKEA GRACILIS. Hooker's Icones Plantarum 33: tab. 3222.
Dyer, R.A. (1976) FOCKEA ANGUSTIFOLIA. Flowering Plants of Africa 43: pl. 1711.
Herre, H. (1968) FOCKEA CRISPA, THE OLDEST AND MOST FAMOUS SUCCULENT PLANT IN EUROPE. Cact. & Succ. Journ. Amer. 40 (6): 245-248, 6 figs.
Klackenberg, J. (1999) REVISION OF THE MALAGASY GENERA PENTOPETIA AND ISCHNOLEPIS. Candollea 54 (2): 257-339, 32 figs.
Kunze, H.; Meve, U. & Liede, S. (1994) CIBIRHIZA ALBERSIANA, A NEW SPECIES OF ASCLEPIADACEAE, AND ESTABLISHMENT OF THE TRIBE FOCKEEAE. Taxon 43 (3): 367-376, 12 figs.
Miller, A.G. & Morris, M. (1988) PLANTS OF DHOFAR. Sultanate of Oman.
Rowley, G.D. (1987) CAUDICIFORM & PACHYCAUL SUCCULENTS. Strawberry Press.
Rowley, G.D. (1990) FOCKEA CAPENSIS ENDL. - THE CORRECT NAME FOR THE "OLD LADY OF SCHÖNBRUNN". Asklepios 50: 25-26.
Venter, H.J.T. & Verhoeven, R.L. (1997) A TRIBAL CLASSIFICATION OF THE PERIPLOCOIDEAE (APOCYNACEAE). Taxon 46 (4): 705-720.
Venter, H.J.T. & Verhoeven, R.L. (2001) DIVERSITY AND RELATIONSHIP WITHIN THE PERIPLOCOIDEAE (APOCYNACEAE). Ann. Missouri Bot. Gard. 88 (4): 550-568.
Venter, H.J.T.; Verhoeven, R.L. & Kotze, J.D.S. (1990) THE GENUS PETOPENTIA (PERIPLOCACEAE). South African Journal of Botany 56 (3): 393-398, 12 figs.
Zecher, E. (1988) THE OLD LADY OF SCHOENBRUNN. Asklepios 43: 88-93, 7 figs. (with an extensive bibliography)