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Succulent EuphorbiasPart 3
The surprisingly large number of species known as the caput-medusae euphorbias (called vingerpols“tufts of fingers”in Afrikaans) all come from South Africa or nearby regions of neighboring countries. The best known of these medusoid plants, the eponymous Euphorbia caput-medusae, grows essentially within the city limits of Cape Town, in the hills that run alongside the city. As might be expected in a plant from a well watered area, it can become quite large, almost three feet across, looking like a great swirl of spiraling and twisting tubercled stems a foot or so in length, that emerge out of a central, thickened, cylindrical stem. Unlike most of the other medusoids, however, it lacks a flattened or depressed, branchless area at its apex, the head, as it were, from which the snake-like branches (Medusa’s hair) can emerge.
The vingerpols once were divided into those plants in which the five glands surrounding the central flower parts had fringing, filamentous processes and those which didn’t. Though not presently considered taxonomically significant, the unfringed and fringed flowered medusoid euphorbias form fairly recognizable horticultural associations. The non-fringe flowered plants, with uniformly green stems and branches, flower from their distinctly depressed central stem and the bases of the branches rather than farther toward the branch tips. Their range extends eastward from the central southern coastal regions of South Africa. They form a sort of continuum, from small to larger and with shorter to longer secondary branches depending on the ecological conditions in which they grow. The small end of the continuum includes species such as the generally solitary E. gatbergensis and the slowly clumping E. ernestii, both with bright yellow flowers. The brown-purple flowered E. gorgonis and the green flowered E. pugniformis become a bit larger, then E. franksiae and the commonly cultivated E. flanaganii (both also with yellow flowers) a bit larger still, and finally the largest, E. woodii, from warmer, better watered areas, has a main stem up to six inches across, and twenty or more swirling secondary branches that can triple its total diameter. With similar unfringed, shiny yellow flowers, but a very different appearance, E. clavariodes, from high in the mountainous regions of eastern South Africa and the enclosed neighboring country of Lesotho, has a main stem that subdivides into a great many short, somewhat club-shaped secondary stems, forming either a large, dome-shaped mound up to a yard across, or, in its variety truncata, a somewhat smaller disc as flat as a pancake, its myriad secondary branches all uniform in height and making a sort of knobby green pavement. Along with a general dwarfism related to more arid conditions, the smaller plants in this group tend to have shorter secondary branches, reaching the ultimate with the possibly mythical E. brevirama, a very small plant with a whorl of secondary branches less than half an inch in length. The desire to find E. brevirama (which may have simply been a stunted or aberrant example of something else) has led to the discovery of a panoply of small medusoids in recent years, mostly by Gerhard Marx. Though many of these discoveries undoubtedly will turn out to be just forms of E. gorgonis and related species, a few may manage to retain taxonomic autonomy. Among these, E. suppressa, from the bleak Great Karoo, has a relatively large cylindrical body, with many very short, thick secondary branches growing from around its apex, while E. atroviridis looks like a smaller version of either E. clavariodes, from far to the east, or E. ramiglans, from far to the west. Both E. supressa and E. atroviridis live in the central South African interior, a harsh region of blazing summer heat, little rain, and bitterly cold winters.
The fringed flower processes of the other medusoid euphorbias give their blossoms the look almost of little daisies. E. caput-medusae itself lives at the southern end of an arc of species that stretches both to the northwest and to the east and north. To its immediate east live two rather nondescript species, E. muirii and E. marlothiana, dwellers in sandy coastal flats and consequently deep-rooted, but lacking the highly defined central stem that distinguishes most of the members of this group. Moving farther up the coast to the east, and inland to the north, brings a number of less closely related medusoid euphorbias into view. These include species such as E. fortuita, E. esculenta, E. colicullina, and E. inermis, all medium sized plants with well defined, usually light brown or gray-green central stems from which several series of cylindrical branches emerge. In common with several of these plants, Euphorbia albopollinifera, a smaller medusoid relatively recently discovered, has quite striking little flowers with centers surrounded by feathery white processes, while the processes of other vingerpols vary from white, to golden yellow or even red. In species that can produce masses of flowers (in particular E. inermis and its variety huttoniae), the result can be somewhat spectacular, even though we usually think of euphorbia flowers only being prominent in those species in which the actual flowers lie nestled in the midst of brightly colored bracts (think of poinsettias for the most obvious example).
Much farther north and east, as far as Zimbabwe, the few medusoid euphorbia species tend to have longer lived and larger leaves than those in more arid habitats. Euphorbia davyi in particular, a fairly good-sized species, has leaves up to an inch and a half long that remain on its secondary stems for quite a long time. E. maleolens, similar but smaller and with smaller leaves as well, is one of the easiest to grow of these plants, in contrast to E. davyi, which can rot if allowed to get too cold and wet in winter.
Most of the remaining medusoids live to the north and west. Euphorbia tuberculata, rather resembling E. esculenta and the other eastern plants, starts its territory just a bit northwest of E. caput-medusae itself, and follows the winter rain as far north as the Richtersveld. Similar, but smaller, and with more distinctly green flowers, E. confluens grows sporadically over much the same range, often encroaching onto the edges of the Namaqualand quartzfields where so many fantastic succulents live. Restricted to the northern half of this foggy coastal desert, E. ramiglans generally forms a short, stocky main stem with a few branches at the top, but in some areas near Port Nolloth really large plants up to a yard across with innumerable branches embed themselves in old sand dunes a quarter mile back from the sea, in the company of Crassula plegmatoides, Fenestraria rhopalophylla, and hordes of land snails with pure white shells and fleshy, jet-black bodies. E. tuberculata has whitish looking flowers, E. confluens, greenish ones, and the flowers of E ramiglans have yellow or rust colored processes that make them look more like daisies than the others, but the distinctions between the plants are not all that clear and ultimately it may be impossible to sustain them as separate species.
Back from the beaches, several other rare species grow in the quartz hills and stony Namaqualand flats or cross the border into Namibia. Perhaps the most spectacular of these is Euphorbia namibensis, which grows in flats composed of nothing but compacted sand, an unpromising habitat that it shares only with a little very sparse grass. Its central stem, displayed well above ground, look disproportionately massive, as does the whorl of snake-branches that grows from its top. The plants often bend down against the prevailing western winds, and form scattered colonies. Wind-blown sand often adheres to the other medusoids of this area on either side of the South Africa / Namibia border as well. These include thick stemmed plants with very short branches such as E. namaquensis, E. melanohydrata, while the small, short-branched E. pentops, from the Richtersveld hills, has distinctive flesh-pink flowers with an emerald-green spot at the base of each of glandular process. A number of western species grow with a main stem subdivided into several upright secondary stems which in turn put out reduced little “snake” branches, so each stem looks like a miniature version of E. namaquensis. These include E. friedrichiae, E. braunsii, and E. filiflora, plants which, though never common, grow from southern Namibia and the Richtersveld all the way into the Great Karoo. Closely related to E. filiflora, but very localized, E. brakdamensis, from Namaqualand quartz hills, comes with dark green stems, a dense array of secondary branches and green flowers, while E. versicolores, from the Richtersveld, has rather gaudy, multicolored fringe-flowers prominently displayed on long stalks.
The bleak, alternately roasting and freezing, but always arid region of the Great Karoo has a number of these euphorbias living as endemics, rather than wandering in from the not-quite-so-bleak west. The plants tend to be brown or even purplish in color, very hard, with short, stiff secondary branches crowned by persistent, hardened peduncles (flower stalks). Euphorbia arida has an erect main stem and upright secondary branches that fan out from its apex. E. fusca, a bit larger and rather similar, has a distinguishing furrow that runs down its center, while E. albertensis is smaller but rather similar minus the furrow. E. decepta, with an almost round main stem and stiff secondary stems radiating out in all directions, resembles a World War II maritime mine; the plant called E. hopetownensis is smaller but similar. E. astrophora is small as well, slightly less globular, and has distinct starbursts of dried peduncles at its branch tips. E. crassipes forms a low dome of short, thick secondary stems, and the similar E. inornata generally lacks the persistent dried flower stalks that decorate most of the other members of the group.
As with other assortments of medusoid euphorbias, it seems likely that many of these species will eventually be swallowed up, and some botanists have considered lumping a great many of them into what seems to be the most distinctive species of all, the widespread Euphorbia multiceps, a plant that ranges from the Little Karoo, the Ceres Karoo, and far northwest into Namaqualand and the southern Richtersveld. Unlike the other medusoids, that look more-or-less like globes or cylinders symmetrically topped with snake-like secondary branches, E. multiceps resembles a miniature, succulent Christmas tree, with a central stem completely obscured by a dense growth of horizontal secondary branches that grow increasingly shorter from the base of the plant to the top, resulting in an elongated triangle. A colony of these plants looks like a scattering of strange little pyramids, growing in the midst of succulent scrub and low brush. Some forms of E. multiceps are less completely covered with secondary stems, and these plants sometimes are considered variants or even new species, but my feeling (for what it’s worth) is that the very distinctiveness of the classic E. multiceps makes it hard to see plants that don’t take that exact shape as simply different forms, displaying a range of variation typical of most widely distributed species. At any rate, some euphorbia specialists have advanced this line of thought, and advocate submerging many of these odd plants into a greatly expanded definition of Euphorbia multiceps.
Most of these plants are rare in the wild and uncommon in cultivation. The “flanaganii” types grow easily with standard succulent water and soil and bright light, and the same is true with those plants most closely related to E. caput-medusae. The plants from the west coast of South Africa and Namibia live in a winter rainfall region, while the plants from the Great Karoo receive most of their rain in late summer and fall, and some of these plants can prove difficult in cultivation. Summer dryness may be best for the coastal plants, but if the plants decide to grow in summer, we should take advantage of their good nature and water them. A bit less than average water may be advisable, along with extremely rapidly draining soil, for the most arid growing species, and even though it’s widely distributed, E. multiceps can be a challenge to keep alive at all. Less water (if any) when dormant, and careful observation during its growing season is the best way to keep this plant alive, and is a good rule for all the arid growing medusoids. Many of these plants used to be great rarities in cultivation, but several commercial growers have introduced seed-grown plants in good quantities into the trade. Growing a seedling into a natural looking mature plant doesn’t come quickly or easily with some of these euphorbias, but others do grow well and a few will even tolerate outdoor conditions in the Bay Area. The medusa euphorbias have proved a favorite with many growers (myself obviously included), and I’d recommend them to almost anyone interested in succulent plants.
The Garden’s collection of these plants has significantly improved during the last few years, although it’s still far from comprehensive. Many of these plants are very rare, and though some are easy to grow, others are very difficult. Occasionally, though not on a regular basis, we do offer some of these euphorbias for sale.
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