Inflorescence cormlets in Watsonia meriana
Posted: February 6, 2024 Filed under: Botany | Tags: Iridaceae, Watsonia Leave a commentAll corms and cormlets produced by a Watsonia are axillary. Sympodial branching is a diagnostic character of the genus, with the main corm being exhausted by producing an annual flowering stem and one or several new lateral underground corms each subtended by a basal leaf. Additional smaller corms, variously called cormlets, cormils or bulbils are typically produced in the axils of lower cauline leaves in many species including W. aletroides (Burm.f.)Ker Gawl., W. humilis Miller and W. meriana (L.)Miller.
The Watsonia inflorescence is a spike with each solitary, sessile flower subtended by an outer bract and a less robust inner bract. The weedy variety W. meriana var. bulbillifera (J.Mathews & L.Bolus)D.A.Cooke is distinguished by having the lower flowers in its inflorescence replaced by clusters of cormlets. This variety is usually a sterile triploid depending on above-ground cormlets for dispersal, and is known as bulbil watsonia.
However, some genotypes of diploid W. meriana var. meriana can produce small solitary cormlets or cormlet clusters in the inflorescence, at least in cultivation. The extent of cormlet development is variable from one year to another; they are sometimes absent and are never as large or numerous as in var. bulbillifera.
Accession 183. At the right of the picture is a typical solitary cormlet 3mm wide produced in the axil of the reduced leaf subtending an inflorescence branch – but on the outside of that branch. This has been observed on all branches in six out of eight years. To the left is a cluster of six cormlets replacing the lowermost flower on the main axis; this has only been observed once.
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Accession 187. A cluster of three cormlets replacing the lowermost flower of the inflorescence. This has only been observed once in eight years.
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I used to wonder if the cormlet clusters of var. bulbillifera might be homologous to the twelve organs (six tepals, three stamens, three carpels) in a flower. This hypothesis was attractive because, although the number of cormlets in each closely packed cluster is variable, twelve is a typical number. The observations reported here make the hypothesis much less likely. There is a gradient transition from stem cormlets through inflorescence cormlets to clusters. The position of the cormlets in accession 183, axillary to the phyllome subtending an inflorescence branch but abaxial to that branch as if an extra axillary growing point, is rather surprising.
The consistent development of inflorescence cormlet clusters is still the morphological character separating var. bulbillifera from var. meriana. However, the difference should be understood as one of degree rather than a clear dichotomy.
Accession 183 was a gift from Mr Graeme Dallimore who collected it on Mornington Peninsula, Victoria. Accession 187 is said to be Cronin material discarded from Melbourne Botanic Garden in 1995. Both readily produce seed, implying that they are diploids.
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References
Conran, J.G., Wilson, P.A. & Houben, A. (2004). Pollination and ploidy changes in South Australian populations of bulbil watsonia, Watsonia meriana (L.)Miller var. bulbillifera (J.Mathews & L.Bolus)D.A.Cooke (Iridaceae). Herbertia 57: 57-70.
Cooke, D.A. (1998) Bulbil watsonia is a variety of Watsonia meriana (L.)Miller (Iridaceae). J. Adelaide Bot. Gard. 18: 5-7.
Goldblatt, P. & Manning, J.C. (2020) Iridaceae of southern Africa. Strelitzia 42. (South African National Biodiversity Institute: Pretoria).
Herbertia lahue in Australia
Posted: December 19, 2023 Filed under: Botany | Tags: Iridaceae Leave a commentNow that Deble (2021) has clarified the nomenclature of this group of related species, it’s clear that the Herbertia commonly grown in Australian gardens is H. lahue (Molina)Goldblatt, which is remote from H. pulchella Sweet.
Its closest relatives include H. amoena Grisebach and H. caerulea (Herbert)Herbert. These three are sympatric in South America, but H. lahue is the commonest in central Chile, and so may be better adapted to grow autumn to winter in a Mediterranean climate where it continues flowering through spring until dryness forces it to go dormant for the summer. The epithet lahue comes from a Chilean common name.
In my experience of growing H. lahue in Adelaide, it is self-compatible or possibly apomictic, with every flower producing a full capsule of seed after opening for one day. Seed germinates readily after sowing in autumn and plants may flower in their second year. Although perennial, the bulbs do not multiply rapidly and may die after a few years. Like many other r-strategist irids, it depends on seed to maintain a population.
The true Herbertia lahue is recognised by the combination of characters:
– a single flower per spathe (instead of two)
– outer tepals 10–18 mm wide
– anthers straight, 5–7 mm long
– apices of the 3 style branches only shortly bifid and straight (not recurved)
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Reference
Deble, L.P. (2021) Herbertia lahue (Iridaceae) and its allies. Balduinia 17: 2-13.
An Iris resembling Iris aphylla
Posted: November 27, 2023 Filed under: Botany | Tags: Iridaceae Leave a commentMany rhizomatous bearded irises are loosely called “Iris germanica” in Australia, and I have to admit I was guilty of this in the Flora of Australia (1984) and the Flora of South Australia (1986). Even the complex garden hybrids known as Tall Bearded Irises are sometimes lumped under this binomial, although the real Iris germanica L. is highly unlikely to have contributed to any of them, being difficult to use in a breeding program.
Among them are several distinctive cultivated clones; you may find them in your garden, or your neighbours’ gardens, or growing feral on waste ground from plantings several (human) generations ago. It seems approriate to call them clones as they represent a small number of quite uniform phenotypes with no intermediate forms, and rarely if ever produce seed. One of these irises that is frequent around Adelaide resembles I. aphylla L. at first glance, but can only be included in the broadest concept of this species.
It’s clear that the epithet “aphylla” used by Linnaeus in Sp. Pl. 38 (1753) did not mean that the plant is leafless at flowering time, although that may be the case in the colder parts of its historical range, which extends from the Balkans north to Germany and east to Russia. He actually wrote “scapo nudo longitudine foliorum” – with a naked scape the same length as the leaves – implying that he saw leaves and flowers together, as shown in the habit photo at Plants of the World Online. By “scapo nudo” he surely meant that the scape did not bear any leaves apart from the bracts.
Rhizomatous perennial herb to 70 cm high. Leaves in a basal fan of 5-12, ensiform, glaucous, to 37 mm wide, 50 cm long, apices acute and straight or gently incurved, present throughout the year. Scape elliptic in cross-section, to 50 cm tall, naked apart from a bract subtending each of the 0-2 short branches. Bracts slightly inflated, cymbiform, herbaceous but densely purple-streaked. Flowers solitary or paired within the bracts. Perianth tube to 3 cm long. Perianth lobes obovate, to 6 cm long, indigo to dark violet, the outer series (falls) patterned with a dark network on paler ground in the lower part, with a beard of white hairs, those near the haft yellow-tipped. Anthers 15 mm long, white, on 15 mm dark blue filaments. Style branches indigo, shading to almost white at base. Ovary fusiform, 6-angled, to 15 mm long. Fruit and seeds not seen. Flowers in August in Adelaide, long before I. germanica and the Tall Bearded Irises.
Thus it differs from I. aphylla sens. strict. in the leaves, which are seasonal, fewer, broader, and strongly falcate in that species (Dabrowska et al., 2019).
There are several irises in southern Europe close to I. aphylla and included in it by Service (1997) that have also been given names at species level. They may be of hybrid origin (Colosante & Mathew, 2008) but none of them matches the one described above.
Many of the supposed species in Iris Section Iris could be ancient garden hybrids that have been given binomials as if they were actual species that consist of wild populations. It’s a similar story in many horticultural genera such as Citrus, where our familiar oranges and lemons are ancient hybrids bred from less familiar Asian species. Long before the well-documented hybridisation of irises over the past two centuries (Darlington, 1973) there may have been earlier cycles of hybridization, selection, and the survival of some forms as feral populations that botanists in recent times have interpreted as species. My father used to say that history is a lot longer than most people think, and this is surely true of the history of plant domestication.
I. aphylla sens. strict. is a tetraploid with 4n = 48 chromosomes, while I. albicans Lange and I. germanica are reduced tetraploids with 44. All three behave as obligate outbreeders in cultivation; seed can only be produced by hand pollination with compatible pollen. When documented hybridisation began in the 19th century the first Tall Bearded Iris cultivars were diploids produced from I. variegata L. and I. pallida Lam. with 2n = 24, and the contemporary tetraploids and hexaploids are derived from them.
For comparison, here is a plant matching Iris germanica L. in morphology and pigmentation – although I haven’t seen its chromosomes.
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References
Colasante, M. & Mathew, B. (2008). Species of natural hybrid origin and misinformation in the Irises: A reappraisal of the presence of I. aphylla L. in Italy. Plant Biosystems 142: 172-178.
Dabrowska, A., Smigala, M. Denisow, B. & Winiarczyk, K.(2019) Biology of flowering and insect visitors of Iris aphylla L. (Iridaceae). Turk. J. Bot. 43: 798-808.
Darlington, C.D. (1973) Chromosome Botany and the Origins of Cultivated Plants. 3rd edn (Allen & Unwin: London).
Service, N. (1997) Section Iris. In The Species Group of the British Iris Society A Guide to Species Irises. 17-56. (Cambridge University Press: Cambridge).
Watsonia fulgens
Posted: May 1, 2023 Filed under: Botany | Tags: Iridaceae, Watsonia Leave a commentWatsonia fulgens (Andrews)Pers. based on Antholyza fulgens Andrews was regarded as a nomen confusum by Goldblatt (1989) because the type illustration could not be matched to any wild population. Andrews’ description of this plant whch had been introduced to England in 1792 was little more than a diagnosis differentiating it from Antholyza ringens (= Babiana ringens): it had much longer glabrous leaves that remained green until new growth appeared, and bright scarlet, curved trumpet shaped flowers with large spreading lobes.
Ker Gawler (1802) treated it as a distinctive variety of Watsonia iridifolia (Jacq.)Ker Gawl., which is another name of uncertain application. An illustration by Planchon (1856) under W. iridifolia var. fulgens matches a clone that is still widely grown in Melbourne although apparently not commercially available. Planchon noted that it flowered in autumn with a scape to 1-2 metres long, far exceeding the leaves, simple or sometimes branched in vigorous specimens. Plants of this name were being sold in England by 1820 (Loddiges, 1820). In New South Wales, Macarthur (1843) had a plant he called Watsonia iridiflora fulgens and presented material to the Sydney Botanic Gardens in 1831.
The following description is based on accession 180 in my collection:
Evergreen, proliferating, to 150 cm tall. Basal leaves about 4, to 60 cm long, 35 mm wide, bright green with faint glaucous striations and thin green margins. Stem leaves 2, bract-like, slightly inflated. Flowers 24-28 (to 4 open at once) on a brown axis plus 0-2 short branches. Bract acute, to 19 mm long, exceeding the internode, brown-herbaceous. Bracteole subequal, obtuse or notched at apex. Perianth intense orange-red, with a paler star inside throat, alternating red and pale stripes inside tube. Tube to 49 mm long; basal part to 23 mm long; distal part cylindric, curved, to 26 mm long, 8 mm wide at mouth. Ridges absent. Lobes semi-flared with flat margins; outer acute, oblanceolate, to 27 mm long, 11 mm wide; inner elliptic, obtuse, to 28 mm long, 14 mm wide. Stamens closely arcuate with style, anthers 11 mm long, purple with purple pollen. Style branches far exceeding anthers, red with paler stigmas. Capsule cylindric, truncate, to 25 mm long, brown. Seeds with two short wings, 8-10 mm long, dark brown.
Unlike Watsonia tabularis and W. fourcadei, this plant is undamaged by full summer sun in Adelaide as long as it gets enough water. New shoots appear in January while the previous year’s leaves are still green. Flowering is irregular any time from April to September.
There is a superficial resemblance to photos of wild W. zeyheri in colouring: orange-red flowers on a dark axis. But accession 180 is clearly separated from this species by its size, truncate capsules, autumn-spring flowering season, non-thickened leaf margins and the rather characteristic pale star marking in the flowers.
One possible origin could be a garden selection from random hybrids between W. tabularis and W. zeyheri or W. angusta, with strong, hardy growth in cultivation due to F1 vigour. An irregular flowering season is common in Watsonia hybrids between parents with differing phenologies. It also resembles my hybrids of typical W. tabularis pollinated by W. fourcadei in such features as size, flower colour and capsule shape. The four species mentioned in this paragraph are closely related and were treated as the Subsection Angustae in Goldblatt’s revision.
Below is Planchon’s illustration. The prominent leaf venation may be the artist’s interpretation of the striated glaucous bloom emphasising the longitudinal veins.
And the type illustration from Andrews. Assuming it is the same plant as Planchon illustrated, this is less informative. Perhaps it was grown in shaded or otherwise unfavourable conditions, as he described it as only 3 feet tall.
The plant known as Watsonia fulgens has been a “thing” for over 200 years. If it does not match any wild population, perhaps it should be treated as a cultivar. Unfortunately the name has been loosely applied in horticultural literature, for example to W. angusta by Campbell (1986). Watsonia fulgens sensu Montague (1930) was probably a hybrid cultivar; it was described as having pale-rose flowers appearing early in spring. It was distributed by Law Somner (1933) and may have been identical to the Watsonia fulgens described as a deep pink in Brunning’s 1905 and 1918 catalogues.
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References
Andrews, H.C. (1801) Botanist’s Repository 3: t.192.
Brunning, F.H. (1905) Manual of Seeds, Bulbs, Horticultural Sundries. (F.H. Brunning Pty Ltd: Melbourne).
Brunning, F.H. (1918) Winter Flowers, Bulbs, Spring Flowering Sweet Peas. (F.H. Brunning Pty Ltd: Melbourne).
Campbell, E. (1989) Watsonia. In Walters et al. (eds) The European Garden Flora 1: 385-386. (Cambridge University Press: Cambridge).
Goldblatt, P. (1989) The genus Watsonia. (National Botanic Gardens: Kirstenbosch).
Ker Gawler, J.B. (1802) The Botanical Magazine 17: t.600.
Law Somner Pty Ltd (1933) Law Somner Catalogue 1933-34. (Law Somner Pty Ltd: Melbourne).
Loddiges, C.L., Loddiges, G. & Loddiges W. (1820) Catalogue of Plants which are sold by Conrad Loddiges and Sons, nurserymen, at Hackney, near London. (Loddiges: London).
Macarthur, W. (1843) Catalogue of Plants Cultivated at Camden.
Montague, P. (1930) The new watsonias should be freely grown. The Australian Garden Lover 6: 33.
Persoon, C.H. (1805) Synopsis Plantarum 1: 42.
Planchon, J.E. (1856) Flore des Serres et des Jardins de l’Europe. 11: 1.
A partial checklist of named Watsonia cultivars
Posted: July 20, 2022 Filed under: Botany | Tags: Iridaceae, Watsonia Leave a commentWatsonia is a genus of the Iridaceae with about 53 species in southern Africa. They are perennial herbs growing from corms and producing spikes of showy flowers adapted to pollination by birds or insects. The species are generally interfertile, all being outbreeders with the same diploid chromosome number. Their wide range in size, phenology and flower colour, along with the ease of working with their large simple flowers, make them attractive subjects for collectors and amateur hybridists.
During the early 20th century there was interest in commercial production of named cultivars for home gardens and cut flowers, but the genus has been rather neglected since then. The following checklist is a ‘first pass’ through the referenced publications, with a bias toward those cultivars that have been released in Australia. It is not certain if every cultivar on this list is still extant.
You can download the list as a 210Kb pdf file from this link.
Watsonia ‘Leng’
DOI: 10.13140/RG.2.2.16217.39520
Watsonia coccinea
Posted: October 19, 2019 Filed under: Botany | Tags: botany, Iridaceae, Watsonia Leave a commentWatsonia coccinea Herbert ex Baker is native to the South-western Cape in seasonally wet sites on sandy flats.
It has been cultivated in Australia since the 1840s, sometimes under the misapplied name of W. humilis. The earliest recorded importation from the Cape was by Alexander Macleay of Elizabeth Bay via Captain Farquard Campbell in 1838. The specimen illustrated here was purchased from Tesselaars nursery in Victoria in 2002.
In cultivation it grows to 40 cm tall, exceptionally to 1 metre but never with more than 12 flowers. The bright scarlet perianth has an arched, narrow cylindrical tube 4-5 cm long marked internally with six darker red lines, and hooded lobes 24 to 28 mm long.
W. coccinea flowers later than many of the winter-growing watsonias, in late October and consequently the flowers are vulnerable to damage by thrips. It is less useful in the garden than the small forms of W. meriana for this reason, and because it is a “shy bloomer” with some full-sized corms producing only foliage if planted too densely or given less than full sunlight during the winter. It has apparently contributed its flower shape and warm colouration to a few of the cultivars bred by Cowlishaw and Cronin in the early 20th century, crossing with larger plants derived from W. borbonica.
References
Goldblatt, P. (1989) The genus Watsonia. 148 pp. (National Botanic Gardens: Kirstenbosch) ISBN 062012517
Macleay, A. (1843) Plants received at Elizabeth Bay. (Ms in Mitchell Library, Sydney, 2009/115).
Watsonia tabularis
Posted: October 6, 2017 Filed under: Botany | Tags: botany, Iridaceae, Watsonia 1 CommentWatsonia tabularis J.Mathews & L.Bolus has been in cultivation in Australia since the 19th century but does not appear to have contributed to the pedigrees of any hybrid cultivars bred in this country. It is endemic to the Cape Peninsula of South Africa and may be closest to the more widespread and variable Watsonia fourcadei J.Mathews & L.Bolus.
Plants grown from seed recently imported from South Africa have flowers of pale pink with a darker tube as shown in the photo. These represent the high altitude form; plants from lower altitudes differ in having bright orange flowers.
W. tabularis is evergreen, making most growth during autumn and spring then flowering in November to January.
Reference
Goldblatt, P. (1989) The genus Watsonia. 148 pp. (National Botanic Gardens: Kirstenbosch) ISBN 062012517
Watsonia pillansii
Posted: March 17, 2017 Filed under: Botany | Tags: Iridaceae, Watsonia Leave a commentWatsonia pillansii L.Bolus is widespread in the eastern (i.e. summer rainfall) part of South Africa at low and medium elevations. This wide geographic range is associated with variation in ecological requirements and plant size, but the flower colour is generally bright orange to orange-red.
Plants grown from seed recently imported from South Africa have unbranched stems to 1.2 m high bearing up to 22 flowers. They are evergreen, with new shoots appearing in late summer immediately after flowering and before the previous season’s leaves have died. Each flower has a cylindric tube 3.5 to 5 cm long and acute perianth lobes to 24 mm long that flare widely when fully open; the colour in this strain whose exact provenance is unknown is a rather weak orange-juice orange on the lobes and deeper on the outside of the tube. The anthers and pollen are cream.
Watsonia pillansii is related to W. schlechteri in the section Watsonia, subsection Grandibractea.
The species has been in cultivation in Australia since the 19th century. Cultivars that may be selections of W. pillansii include ‘Flame’ (marketed by Lawrence Ball in the 1940s) and ‘Watermelon Shades’ (Cheers, 1997). Watsonia ‘Beatrice’ or the Beatrice Hybrids is a group name for various natural hybrids of W. pillansii (Eliovson, 1968) that were exported to Britain, America and Australia in the early 20th century. The name comes from Watsonia beatricis J.Mathews & L.Bolus, which was a taxonomic synonym of W. pillansii.
References
Cheers, G. ed. (1997) Botanica. (Random House Australia).
Eliovson, S. (1968) Bulbs for the Gardener in the Southern Hemisphere. (Reed: Wellington).
Goldblatt, P. (1989) The Genus Watsonia. (National Botanic Gardens: Kirstenbosch) ISBN 062012517
Watsonia fourcadei
Posted: October 3, 2016 Filed under: Botany | Tags: Iridaceae, Watsonia 1 CommentWatsonia fourcadei J.Mathews & L.Bolus has been in cultivation in Australia since the 19th century but does not appear to have contributed to the pedigrees of any hybrid cultivars bred in this country. It is widespread in the mountains of the southern Cape but absent from the Cape Peninsula where it is replaced by the related W. tabularis J.Mathews & L.Bolus.
Plants grown from seed recently imported from South Africa have flowers in a range of pink shades from pale salmon with a darker tube to the medium pink shown in the photo. They are evergreen, making most growth in mid summer to autumn but flowering in October to December.
The flowers have an arched, narrow cylindric tube about 6 cm long and perianth lobes 26 to 32 mm long incurved to form a cup-shaped limb.
Reference
Goldblatt, P. (1989) The genus Watsonia. 148 pp. (National Botanic Gardens: Kirstenbosch) ISBN 062012517
Watsonia schlechteri
Posted: December 31, 2015 Filed under: Botany | Tags: botany, Iridaceae, Watsonia 1 CommentWatsonia schlechteri L.Bolus grows in the montane veld of the winter-rainfall parts of the Cape, South Africa. Plants grown from seed imported via Silverhill Seeds first flowered this year and are a good match for the lectotype of W. schlechteri.
The flowers are orange-vermillion with perianth lobes to 23 mm long. The buds end in a slightly downcurved point. There are no staminodal ridges in the perianth tube, a character that distinguishes it from the closely related W. pillansii. However, the fresh leaves of these specimens lack the strongly thickened margins and midvein that are used as another distinguishing character; these are only evident in dried material.
W. schlechteri is one of the smaller watsonias, usually much less than 1 metre tall with leaves about 40 cm long. It flowers in late December to January, resuming growth from offsets soon after flowering while the previous season’s shoot may still be green. Thus it has some leaves all year, or non-flowering plants may be briefly leafless before the new growth starts in late summer. Goldblatt notes that flowering in the wild is conditional on the plants not being shaded out by surrounding vegetation.
Like other watsonias native to high altitudes, it is at risk of damage in the agonisingly hot, dry summers we get here at sea level in Adelaide. The problem is to give the plants sufficient light without excess heat, a tall order on days of 42°C with northerly winds.
Reference
Goldblatt, P. (1989) The genus Watsonia. 148 pp. (National Botanic Gardens: Kirstenbosch).
ādarśajñāna 