Eduart Zimer - (SDU) - Adventive Plants - Part 8 (2009)

Succulent plants from down under Adventive Plants (Part 8):

The bid for succulence: Calystegia soldanella - Bits and Pieces (Natures potting mix for succulents / New pictures)

XIX. The bid for succulence: Calystegia soldanella

Before we start I have to clarify few things the well known Calystegia soldanella (Linnaeus) R. Brown 1810 (basyionym Convolvulus soldanella Linnaeus 1753, heterotypic synonym Calystegia sepium var. tangerina Pau 1924), which is in fact an invalid name (1), correctly being referred as Calystegia soldanella Roemer & Schultes 1819, is actually not a naturalized or adventive, but a cosmopolite plant spread in both hemispheres. It belongs to Convolvulaceae, the Bindweed family. Calystegia soldanella is indigenous in New Zealand (North Island, South Island, Kermadec Islands, Three Kings Island, Stewart Island and Chatham Islands). Beside its English widely used common names like Shore Bindweed, Sea Bindweed, Sand Bindweed (or Convolvulus in some variants) or beach Morning Glory this plant is also known here by its Maori names of Rauparaha, Pohue and Nihinihi. Therefore Calystegia soldanella is not a naturalized plant, but is not exactly a native either (2) (3). Basically it grows in both hemispheres mostly in temperate to temperate with sub-tropical influenced oceanic climates. To make it worse for my decision to include this plant into an account dealing with New Zealand naturalized succulents it is not even a typical succulent. In other words if you are strictly a succulent freak, please skip this chapter!

Calystegia soldanella is a glabrous perennial herb with creeping rhizomes and slender much branched aerial succulent stems, mostly trailing, rarely twining, and forming usually small patches which can reach in some cases over 200 cm across. The petioles are usually 10 60 mm long, occasionally up to 80 mm long, and slender, in most cases longer than the leaf. The leaves are (10) 15 50 (80) (10) 20 50 (75) mm, usually

1. A splendid young flowering Calystegia soldanella growing in pure sand in Opoutere (Coromandel Peninsula).

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sub-succulent, in certain circumstances becoming either membranous or succulent, glossy, covered with a thick waxy protective coating giving the leaves sometimes a leathery aspect, entire, more or less reniform (4) with a usually shallow and rounded sinus, with the base often broad cuneate; the apex varies quite a lot from clone to clone from emarginated to rounded to acute. The flowers are solitary and pleaded and folded in bud. The ribbed peduncles are usually 15 70 mm, on occasion up to 100 mm long (longer than the petioles), the bracts are broad ovate, obtuse, (10) 12 15 (18) mm long, the sepals are obtuse, very similar to the bracts. The corolla is pink to purplish, mostly with white mid-stripes, occasionally all white, 20 40 x 25 50 mm, funnel-shaped (campanulate). The ovaries are surrounded at the base by a nectar-secreting disc. The capsule is ovoid to broad ovoid, 1215 mm long, apiculate. The seeds are dark brown and smooth. The flowering period is October to The flowers are hermaphrodite (have both male and female organs) and are pollinated by bees, moths and butterflies. March and is fruiting in March in the southern hemisphere of course.

Calystegia soldanella can be easily distinguished from other similar species due to its kidney-shaped leaves, but it can form also hybrids with indigenous and introduced Calystegia species (namely Calystegia tuguriorum), the hybrids being also easily distinguished by the sub-succulent stems and leaves sub-succulence being not an ordinary feature of the Convolvulaceae family and by the intermediate leaf form, oscillating between reniform and deltoid (as in the majority of the Convolvulaceae). It is also suspected that natural hybrids with Calystegia sepium ssp. roseata and Calystegia marginata may occur in New Zealand, although this hasnt been documented yet (New Zealand Plant Conservation Network).

Being a cosmopolite species no wonder that it is also polymorphic. The polymorphic character relates not only to general morphologic features having a zonal representation, but very interesting particular habitat conditions can generate different growth forms. However, most of the morphologic variations based on genetic differentiation analyzed by Takanori Ohsako & Gakuto Matsuoka (2007) in Japanese shoreline populations isolated from inland populations for up to 800,000 years (5) have occurred not between individuals from different populations, but 80% of them occur within the same population.

2. Calystegia soldanella in Wreck Bay, in the northern parts of Rangitoto Island. The substrate is a bit different; the plants seem to prefer the limit of the beach where the lava fields begin. Note the organic debris accumulations and the moist sand.


3. Calystegia soldanella flower detail of one of the Opoutere plants. These plants are not very prolific flowerers, but note the number of buds present in a small area.

4. Larger patches of Calystegia soldanella growing in pure sand on the beaches of Opoutere.


The most interesting fact is that Calystegia soldanella usually growing on beaches or fore dunes in xerophytic conditions has very fleshy, succulent leaves, capable to store a certain amount of water in order to overcome the draught; upslope plants growing more or less hidden between higher vegetation in moist and sheltered positions have membranous leaves (more like the other Calystegia or Convolvulus species have). It also can re-convert in a typical climber, usually on scrubs, in search for better light. In other words this plant has definitely placed a bid for succulence, but seemed to have stopped halfway through, becoming a static, slow to non-evolutionary species at least seeing habitat pictures of Calystegia soldanella from all over the world this is my gut feeling. The interesting thing is that it can easily revert (so to speak) to membranous growth forms depending on the habitat characteristics; it seems to have kept a copy of previously functional genetic setups. I havent seen plants with membranous leaves but it was obvious to me that plants growing in more hostile conditions have also fleshier leaves. On top of that its thick, fleshy roots are also designed to store precious water and nutrients. More, the waxy coating of the leaves prevent excessive perspiration. Definitely, we have enough features to which could be regarded as a bid for succulence, even if marginal in this instance.

But despite all these remarkable adaptations Calystegia soldanella seems to have stopped its evolution toward succulence, abandoning the evolutionary traits followed independently by other plants. The most relevant thing is that Calystegia soldanella still uses the usual C3 photosynthesis (6) most plants have, and this is definitely not that common in succulent and xerophytic plants. For a plant with xerophytic adaptations C3 photosynthesis brings a lot of disadvantages like photosynthesis taking place on the entire leaf surface and only on the leaf surface and only during the day (therefore all conditions for a high perspiration rate are present). C3 photosynthesis is more efficient under cool, moist and moderate light conditions and also, by being the first mark of this remarkable physiologic design which is photosynthesis, has maintained the basic but very functional physiology involving less engineering to make all this work fewer enzymes and no specialized anatomy (7).

5. Leaf detail of a plant from Wreck Bay in Rangitoto. Note the typical leaf form, its sub-succulence, the glossy appearance and the tiny apical soft spike you dont see in all plants.


6. Trailing stems on a rocky substrate in Wreck Bay (Rangitoto Island).Compare the leaf form of this plant with that of the plant in picture no. 5, from the same location, just 20 or 30 meters away.

7. Calystegia soldanella growing in pure sand in Raglan (Waikato), at the Tasman Sea.


Although it has outspoken xerophytic adaptations Calystegia soldanella always prefers the vicinity of the water; as it has a moderate salt resistance it usually grows in coastal habitats, but also sometimes inland along lake shorelines (8). It prefers moderate dry to slightly damp sandy or shelly beaches, banks, sand dunes or fore dunes, but is relatively common also in drier gravely or rocky areas (as I have seen in Rangitoto), advancing even occasionally in coastal turfs or on cliff faces, or even up to 30 meters upslope in grassland. Especially in sand or very open sandy soils the stems run under the surface with leaves emerging from the sand; what seem to be different plants could be one and the same.

However, it requires a certain amount of moisture in the air or substrate deep down under the surface of the sandy beaches there is also moisture available and definitely good light (it simply cannot grow in shaded positions). In its typical state Calystegia soldanella is a sand dune pioneer, establishing quickly in exposed positions and becoming locally dominant, but less inclined to face the competition of other plants. It is regarded as a very useful sand-binding plant due to its rhizomatous habit and matted, trailing stems (Flora of Tasmania online).

Like many of the bindweeds, Calystegia soldanella is also known from cultivation. It makes a wonderful display when placed in full sun, in sandy or rocky well draining soil. It accepts anything from slightly acid to neutral to slightly alkaline soils, but does not like too much organic compounds. It is very easy to propagate by fresh seed sown directly in situ in cooler periods of the year (and if you have enough patience as germination can take 1 3 months at 15 degrees Celsius) or in a cold frame if freezing winters in your area, cuttings made in summer (lay them simply on the ground and cover the cut area with sand) or division of the rhizomes very efficient when made in early spring while the plant is still dormant and especially when seed grown plants are divided. I imagine it would make a nice display with its long lasting showy flowers and green glossy leaves. It is also quite hardy; adult plants can stand moderate frosts, but not seedlings. But even if it looks to be one of the toughest, hard to kill plants, actually it is not. It usually is quite difficult to establish in typical gardens because it simply does not like heavy and rich substrates, but given the right conditions you cant stop it! Once established, you have just slim chances to eradicate the plant, as it starts again from seed, rhizomes or rooted stem fragments.

Calystegia soldanella is not only (potentially at least) a nice garden plant, but has also in a certain extent medicinal uses. It has a well known purgative effect (oh well, say side effect), in fact the Plants for a Future database lists antiscorbutic, diuretic, febrifuge, irritant, purgative and vermifuge properties.

The plant has also culinary uses. Young shoots are cooked as a vegetable or pickled and used as a samphire substitute I imagine it cant be a gourmet meal even if we speak here of international cuisine, but still it used to be an ingredient in survival meals. The New Zealand Plants Conservation Network gives also a quite peculiar use: The Maori gathered the thick, white, fleshy roots and pounded these to form a pulp; this was then used as a relish to flavour some meats.

The economical importance even if marginal does not stop here; again Plants for a Future database: The stems are very flexible and are used as a string for tying. Fairly strong but not long-lasting.

I have seen Calystegia soldanella in several locations (it is common, not threatened), but always on the seashores, growing in anything between pure sand to stabilized sand dunes, except the Rangitoto plants, growing on rough gravel in the northern parts of the island (namely in Wreck Bay). It is a plant you usually dont notice, its not striking if not in flower. But at some stage in December 2007 during a visit at the Opoutere beach (Coromandel Peninsula), a splendid and little altered coastal habitat, I have noticed the uniqueness of this plant growing in pure sand. It is not present in large numbers, but you can see here and there patches of Calystegia soldanella with leaves rather on the succulent side, as it is a quite dry environment here,


especially in high summer. The other well represented plants here are Cakile maritima ssp. maritima (again in its succulent version) and Spiniflex sericeus. In a similar habitat at Raglan (Waikato) Calystegia soldanella grows in pure sand as well, but being on the west coast at the Tasman Sea I reckon it gets more rain than the Coromandel Peninsula plants.

At Piha (west of Auckland) Calystegia soldanella grows on very exposed beaches westerly winds spread fine particles of salty sea water well away from the waterline but also on the fore dunes again accompanied usually by Spiniflex sericeus.

The Rangitoto plants grow on a different substrate. As there are no sandy beaches in Rangitoto Calystegia soldanella had the only choice to accommodate on the rocky or gravely shores of the island. As the seeds are quite salt resistant the dispersal occurs by sea currents, waves and tides. I imagine that being close to the mainland Rangitoto would be a target hard to miss. It was very interesting to notice the differences in leaf form displayed by plants growing very close to each other. Unfortunately, my targets for the trip were set and days are never too long on Rangitoto, I took just few pictures and continued my way.

I have to admit that I wasnt interested in this plant until the austral summer of 2007/2008, when I saw the flowering plants on the Opoutere beach. But as a matter of fact, even if most of the botanists and plant enthusiasts do not regard Calystegia soldanella as a succulent plant, I think this plant has definitely placed a bid for succulence at some stage in its early evolution. Evolutionary convergences with known succulent species are easy to observe a certain degree of succulence (sub-succulence in botanic English, Id like to call

8 9. Another flowering plant in Opoutere (below) and a very nice relatively modern drawing of a Calystegia soldanella extracted from a 20th century herbal written by M. Grieve A Modern Herbal (1931) (right).


it marginal succulence) of the stems and (especially relevant) of the leaves and the waxy coating of the leaves which prevents perspiration and protects the plant against lashing winds and sea water mist.

XX. Bits and Pieces

Natures potting mix for succulents

We worry much too often about how much grit or sand or humus or moisture retainers or whatever compounds shall we add to the potting mix we prepare for our cacti and other succulents. Of course, you cant compare potted conditions with free root run conditions in gardens and none of these with the challenges of life in the wild. The amazing thing is that only looking around at wild living plants you can actually understand how much they can take, and how little they need to be pleased. I find it extremely useful to take some time and look at the substrates some succulent and non-succulent plants grow in nature on. The following pictures (some of them being already published elsewhere) are only a very small glimpse of natures secret potting mix recipe for succulents. Im not prepared for a lecture on this, but just have a look and have some thoughts.

10. Some succulent plants are able to thrive in (or only in) pure sand like this Cakile maritima ssp. maritima from Opoutere (Coromandel Peninsula). The coastal sand dunes and beaches environment is actually not that hostile as you think it would be and even if the surface becomes extremely hot in high summer just few centimeters below the surface the deep roots stay in a relatively cooled substrate. Sand also has good water retention and 30 or 40 centimeters deep there is always some moisture available. There is a downside though a certain degree of salinity associated with sometimes high Calcium content (given by the crushed shells). And by the way - in most of the cases the total lack of organic nutrients makes them fight hard every single day.


11. In estuaries or salt marshes margins towards the sea, where the sand is usually wetted periodically by tides or waves with a certain dynamic, pure sand is often replaced by a mixture of sand, shingle, rocks and crushed shells like this substrate Sarcocornia quinqueflora ssp. quinqueflora (a native succulent chenopod) from Miranda grows on . When for some reasons the area is raised or becomes permanently exposed more plants can establish. A good candidate for a succession plant is Carpobrotus edulis. Of course, the easy-to-get nutrients problem hasnt been solved yet. Once left to dry out this kind of substrate improves its drainage.

12. This substrate Sedum album from Rangitoto is growing on looks similar to the one above, but actually it is not. The main difference is given by the rocky base (lava fields in this case) and a certain elevation above the sea level. It is definitely much drier, but it contains more or less the same mixture of sand, shingle, rocks and shells. Whatever the reason is high seas, storms, flooding this accumulation of sediments is usually reasonable superficial and dries out fairly quickly even after torrential rains as water has nowhere to accumulate (except for small pockets) and simply flows away. Several types of vegetation can establish depending on the particular conditions and more or less decayed organic debris can form a layer or mix with the soil.


13. This is Cotyledon orbiculata var. orbiculata growing on Lion Rock, Piha, west of Auckland at the Tasman Sea. This is a high rocky colossus in the middle of the beach and in some places a considerable accumulation of sand and clay particles brought by the strong winds has been formed on milder slopes. Humid air from the sea has helped this soil to compact and later on emerging vegetation has added organic debris and decayed matter, roots have bound everything together. A thin layer of soil has been formed over a long period of time, being the life support for varied vegetation forms. I am not a geologist but it is clearly that this soil has little in common with the surrounding beach and fore dune areas.

14. Carpobrotus edulis the yellow flowering form at Tahuna Torea (Auckland). The substrate is similar to that in picture no. 11 but the site is just a bit more elevated. Dense mats of vegetation allow organic debris to accumulate and decay, eventually changing the texture of the soil. When the conditions come right, succession vegetation will take over forcing pioneers like Carpobrotus edulis to move elsewhere, where seabed has been for some reason uplifted and became permanently exposed. Of course, there are a lot of factors which can derail this process and change the characteristics of the site, but if left alone and this can also happen in only few decades we may find on the same spot pampas grass growing.


15. This fine Kindergarten for succulent plants tells us a different story. The substrate is different from the picture no. 12 because it has less fine sand particles more traces of volcanic ashes (which is not necessarily very fine), and a thin crust of pebbles and gravel. This type of substrate seems to work very well for young Aloe maculata and Crassula tetragona ssp. robusta. Under and between these medium sized particles remains some moisture available for some time, where seed, leaves or rhizomes have just enough to create new plants. This kind of substrate does not occur on large surfaces but is rather restricted to smallish patches between lava blocks.

16. Compared to the previous picture this is a step further. These Agave americana plants from Rangitoto use very wisely the fissures or the small crevices between lava blocks, where accumulations of volcanic ashes or smaller rock particles retains the moisture. In this particular Agave colony there are no higher vascular plants, but lichens, mosses (in moist positions) and xerophytic grasses are growing instead from the smaller sized pockets of soil. In this particular case the above mentioned vegetation types create a more composite vegetation pattern of the ground layer.


17. Well, I should have started probably with this picture. The typical vegetation succession is bare rocks lichens small vascular plants, but in shaded places mosses can cover the ground almost completely. The substrate in this picture is similar to that in picture no. 15 but the vegetation development path will be very likely a different one. Mosses retain moisture and in time dead and decayed plants will create a thin layer of fertile organic soil. Instead of succulent plants there will be probably fast growing non-wooden high mass vegetation established here in some time, changing and preparing the environment for a repeated succession. As this picture was taken close to the bush limits it will be eventually conquered sooner or later by this.

18. This eroded coastal habitat from Paihia (Northland) is very interesting because it clearly shows how thin the fertile layer of the soil sometimes can be. On a thick layer of sandstone a bush like vegetation has established for a long time, it could be many hundreds of years. However, probably nowhere in this area the fertile soil layer is deeper than 20 40 cm. It is most likely the norm here on elevated platforms. Although the only succulent plant I could see here was Crassula multicava, I think there are virtually good chances for other succulents to establish on the borders of the dense vegetation where the soil is relatively often disturbed.


19. This rocky outcrop in Rakino Island (Hauraki Gulf), how hostile it may look, is still home for several plants Disphyma australe ssp. australe and Sarcocornia quinqueflora ssp. quinqueflora in this case. These kinds of platforms have always some sort of cracks, or fissures, or pockets where precious moisture can be available for the plants. Nick Perrin (the editor of the CSSNZ Journal) and the author of an 1996 article on the native horokaka (Disphyma australe ssp. australe) told me once that these small endemic mesembs can send their roots up to 2 meters deep following the cracks of the rocks in search of precious moisture.

20. This is the image of a wet sandstone rock on Rakino Island (Hauraki Gulf); being a sedimentary rock its texture is prone to form cracks and fissures when exposed to the natural elements. It is also very porous and keeps traces of moisture even deep inside. Sandstone is a preferred substrate for many xerophytes and succulents because it never dries out completely deep inside; it is for the plants just a matter of sending their roots and stay connected to a minimal source of moisture which can be the difference between life and death in times of draught.


21. Vertical cliff faces are not a problem for some plants like Cotyledon orbiculata var. orbiculata growing on a tiny lodge on Lion Rock (Piha). The big advantage is that even in humid climates because the rainwater flows away instantly xerophytes can have their portion of draught. This particular spot knows also excellent natural ventilation; strong breezes are battering almost continuously the area, which is again for their best. Seeing Cotyledon orbiculata var. orbiculata in several locations here in New Zealand I imagine this is the optimal habitat for this type in South Africa as well.

22. It is not always a matter of cliffs and sandstone and fissures and cracks, or of pockets of organic accumulations wisely retaining moisture for the days of draught to come that makes the delight of succulent flora. This rough lava field few hundred meters from the southern wharf of Rangitoto is frequently battered by winds laden with sea water. When this particular condition occurs, you cant expect too much but only halophytes to establish like Agropyron junceiforme grass in this particular case. I havent seen Disphyma australe ssp. australe here (another good candidate) but patches of Sarcocornia quinqueflora ssp. quinqueflora were present close to or within the splash zone.


23. A sandstone cliff in Russell Bay of Islands (Northland) in a spot with strong marine exposure bearing some vegetation (the small tussock in the centre is Sarcocornia quinqueflora ssp. quinqueflora). In more sheltered positions an almost continuous strip of Crassula multicava is growing at 1 meter above the high tide mark.


24. Well, I have captured in this picture all prerequisites we need to make my point we have the porous sandstone rock, we have the fissures and pockets, and we have a very healthy Disphyma australe ssp. australe making the best out of a given situation on Rakino Island (Hauraki Gulf). It is not a singular occurrence, but several plants were scattered on the rock surface, some of them of flowering size and bearing numerous seed pods. This is a detail of the rocky outcrop seen in picture no. 17. As you can see lichens have tried as well to make a living here.

25. A similar example is given by this picture this time at a certain distance from the sea in Rangitoto a tiny seedling tries to establish on rough and fragmented lava fields and eventually it will succeed. There is a difference though at this distance (possibly 150 200 meters) from the sea and somewhat sheltered by some bush patches placed in between, there is no cooling breeze, but an incredible heat emanated by these basaltic lava fields especially in high summer during sunny days. Reportedly the rock surface reaches 70 degrees Celsius, hot enough to cook some eggs. The survival of this plant seems quite improbable, but hey - this picture was taken in high summer! Also remarkable is that here plant colonization has just begun.


26. In similar conditions grows this Crassula tetragona ssp. robusta on the lava fields of Rangitoto. The difference is that this particular spot lichens are already very established and some other plants have also tried their luck I the past. Again, the plant is speculating perfectly the opportunity given by the moisture retained in the cracks and the possible traces of organic matter generated by the decayed lichens and smaller vascular plants. Without a proper organic layer the heat is almost unbearable in this open space not very close to the sea.

27. The ultimate success a small plantlet has established in a narrow crack in the rock, surviving killer heat and heavy draught for years and years, growing eventually into a big tree! It is kind of a miracle, as there is no groundwater here in Rangitoto. It also proves that no matter how harsh the environment, no matter how big the losses there are always winners in the vegetal world.


New pictures

As a bonus for this issue rich in illustrations here is a selection of 9 pictures of naturalized succulent plants I havent published before.

28. A small Agave americana in Rangitoto from the small colony halfway between the Islington Bay wharf and the passage to Motutapu Island. By the time I took this picture (January 2009) the colony was checked and all bigger plants removed or (in two cases) simply half uprooted and butchered on the spot. However, several smaller plants from 30 - 40 cm plants to small plantlets like this one still exist.

29. This is the flower of Tradescantia fluminensis - also called The Wandering Jew for the rapid spread it can achieve a creeping South American groundcover with fleshy leaves and succulent stems. I took the picture at Eastern Beach (Auckland) at the southern end of the beach, where the vertical cliffs start. This is a hot spot where several invasive naturalized plants can be seen.


30. Thats me with an unidentified Agave sp. in Mellons Bay (Auckland). It is a survivor plant, not because of the harsh conditions, but because of the sheltered, moist and excessively shaded position, surrounded by dense vegetation which is even worse! Probably it originates from garden waste disposed on the beach; I couldnt see any other Agave on the beach or on the higher grounds in the back. To be honest, I didnt put too much effort in identifying this plant; however, I am convinced that it definitely has an untypical growth.

31 - 32. Details of the unidentified Agave sp. in Mellons Bay.


33. This Aloe arborescens is not exactly a wild plant, but still survives in an abandoned garden in Western Springs. I have inserted this picture more to allow a direct comparison of this neglected plant with the true survivor specimens of Rangitoto (see in Part 7).

34. Carpobrotus edulis at Tahuna Torea (Auckland), a small salt marsh I have already mentioned several times before. Succulent plants have a limited occurrence here (the other succulent plant I have seen is Sarcocornia quinqueflora ssp. quinqueflora) but still it is a wonderful piece of nature.


35. Carpobrotus edulis growing together with Gazania rigens on the Port Waikato fore dunes. These have been massively eroded in the past, so that basically any type of vegetation is welcomed. It is not quite conservation but it is a start. However, the amazing thing is that nature took course on its own. At this stage the area is simply closed for camping and provides only limited public access with the results you can see.

36. Yucca gloriosa a glorious xerophytic plant indeed with marginal succulence growing on the fore dunes of Port Waikato. There will be a short account on this plant in the months to come take this as a preview!


Additional References:

African flowering plants database;

An Encyclopedia of New Zealand, 1966;

H. H. Allen Flora of New Zealand (Vol. 1, Government Printer, Wellington, 1961);

H. H. Allen Flora of New Zealand (The updated electronic version, Vol. 1, 2004 - http://floraseries.landcareresearch.co.nz );

Flora of Tasmania online - http://demo1.tmag.tas.gov.au/treatments/families/Convolvulaceae/Convolvulaceae.html;

M. Grieve A Modern Herbal (1931);

The International Plant Name Index - http://www.ipni.org/index.html;

Native Plants at Piha - http://www.piha.co.nz/natives.htm;

Takanori Ohsako & Gakuto Matsuoka - Nucleotide sequence variability of the ADH gene of the coastal plant Calystegia soldanella (Convolvulaceae) in Japan (2007);

Kathleen Robson, Alice Richter, Marianne Filbert - Encyclopedia of Northwest Native Plants for Gardens and Landscapes (2007).

Further Readings:

Ute Drobner & al. The sand dune vegetation of Chrystalls Beach, Southern New Zealand, with particular reference to the cushion community;

Frances C. Duguid - Botany of northern Horowhenua lowlands, North Island, New Zealand (1990);

A. E. Esler - Botanical features of Tiritiri Island, Hauraki Gulf, New Zealand (1977);

Plants for a Future - http://www.pfaf.org/database/plants.php?Calystegia+soldanella;

C. J. Webb, W. R. Sykes, P. J. Garnock-Jones - Flora of New Zealand (The updated electronic version, Vol. 4, 2004 - http://floraseries.landcareresearch.co.nz );

My Notes:

(1) A comment from The International Plant Name Index: Brown did not make this combination on p. 483; his citation of "C. Soldanellae L." on p. 484, if considered as Calystegia, was still only provisional. In a discussion clearly concerning Calystegia reniformis Robert Brown compares it with C. soldanella L. wondering if there were distinct species: "Obs. Facies C. Soldanellae L. diversa praecipue pedunculis teretiusculis: an vere distincta species?" Even if we could interpret that C. soldanella means Calystegia soldanella and not Convolvulus soldanella but indicating Linnaeus as authority this assumption becomes extremely doubtful the combination Calystegia soldanella (L.) R. Brown would be invalid and has to be regarded as a personal comment simply because Robert Brown did not expressly indicated that he accepts or promotes a new combination. However, some authors consider the two names being synonyms. The generally accepted nomenclature is:

Calystegia soldanella (Linnaeus) Roemer & Schultes 1819. Calystegia soldanella (Linnaeus) R. Brown 1810, nom. inval. Calystegia soldanella (Linnaeus) Choisy 1845 (?). Convolvulus soldanella Linnaeus 1753 (basionym). Calystegia soldanella var. australis Endlicher 1883, nom. illeg. Convolvulus sepium var. soldanella (Linnaeus) C. Moore & Betche 1893. Convolvulus sepium var. saldonella F. Mueller 1875, nom. inval., nom. nud. Note saldonella (sic). Calystegia reniformis R. Brown 1810. Convolvulus reniformis (R. Brown) Sprengel 1824.

(2) Even NZ authors have a dual position i.e. by being referred in both vol. 1 (indigenous plants) and vol. 4 (naturalized plants) of Flora of New Zealand.

(3) We cannot be even sure that native stock has not been mixed in the past with overseas plants, as it happened to other relatives. See Calystegia sepium (Linnaeus) R. Brown ssp. roseata Brummitt 1967 x Calystegia silvatica (Kitaibel) Grisebach ssp. disjuncta Brummitt 1967 ex http://eduart.page.tl.

(4) Reniform means kidney shaped.

(5) Since Calystegia soldanella does not have long-distance terrestrial dispersal systems (Takanori Ohsako & Gakuto Matsuoka, 2007) inter populations gene exchange is not a credible explanation for the relative uniformity. However, I think that based on the global distribution of the species indicating an ancient


origin the isolation period of the populations analyzed by Takanori Ohsako & Gakuto Matsuoka considered to be mostly between 500,000 800,000 years is not long enough to be responsible for a relevant genetic differentiation in a such static, old timer species.

(6) It is called C3 because the CO2 is first incorporated into a 3-carbon compound.

(7) For example there is a single enzyme (Rubisco) involved in both photosynthetic processes and CO2 intake.

(8) For New Zealand Lake Taupo is a very good example.

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All errors, omissions and misconceptions are mine.

Eduart Zimer, August 2009

http://eduart.page.tl/Home.htm


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Eduart Zimer - (SDU) - Adventive Plants - Part 8 (2009)

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