Kalanchoe, , Descoings, 2003

Shtein, Ronen & Smith, Gideon F., 2021, A revision of the climbing kalanchoes (Crassulaceae subfam. Kalanchooideae) of Madagascar including the description of Kalanchoe sect. Invasores and K. ser. Vilana, Phytotaxa 482 (2), pp. 93-120 : 114-116

1. Kalanchoe × poincarei Raymond-Hamet & Perrier de la Bâthie (1913: 149) , pro sp.

Type:— MADAGASCAR. Toliara province (now the Atsimo-Andrefana region ), bord de Menarandra, June 1910, [ J. M.] H.[ A.] Perrier de la Bâthie 11816 (holotype, P P- P00431384 ! [Image available at http://coldb.mnhn.fr/catalognumber/mnhn/p/p00431384]) .

Description:—see Raymond-Hamet & Perrier de la Bâthie (1913: 149), with the following amendments: margins fully, deeply, dentate, many-toothed, especially apical teeth subducted by pale organogenic and/or embryogenic pedestals, and, often bulbils proper, or abscission scars after bulbil detachment; bulbil production constitutive.

Parentage:—Either Kalanchoe beauverdii × K. daigremontiana , or K. beauverdii × K. rosei , if a hybrid (see discussion below).

Distribution:—Around Menarandra, southwestern Madagascar. South Atsimo-Andrefana region ( Fig. 7 ).

Discussion:— Kalanchoe poincarei was at first described as a species based on only one known plant collected near the Manarandra River in the drier woodlands of southwestern Madagascar (Raymond-Hamet & Perrier de la Bâthie 1913: 149, Fig. 5A ). In subsequent synopses of the genus, K. poincarei was treated as an accepted species (see for example Jacobsen 1977: 288, 1986: 624, Boiteau & Allorge Boiteau 1995: 120). However, those works confused K. poincarei with material included in the distantly related K. gastonis-bonnieri species cluster, perhaps due to mislabeled illustrations as well as living material in cultivation at “Les Cèdres” that were originally identified based on Hamet’s unpublished and undated notes, “Clef des Crassulacées malgaches”, where the name “ K. poincarei ” was interpreted as applying to a relative or form of K. gastonis-bonnieri from Bemarivo, northern Madagascar ( Descoings 2005a: 8–9). In the same year, Rauh (1995a: 14), in contrast, argued that K. poincarei is indeed, as originally described, a climbing species of Kalanchoe , and discussed it along with the K. beauverdii cluster of climbing species.

Descoings (2003: 169–170) at first followed the views of Boiteau & Allorge Boiteau (1995: 120) by stating “This species is very close to K. gastonis-bonnieri […]”, but two years later amended his views and acknowledged a relationship between K. beauverdii and K. poincarei ( Descoings 2005a: 6) . In this 2005 work of Descoings he acknowledged that the broad circumscription he earlier followed for K. beauverdii ( Descoings 2003: 147) makes K. poincarei virtually indistinguishable from K. beauverdii . However, he also suggested that K. poincarei is rather a hybrid between K. beauverdii and an unknown other species of Kalanchoe , and published K. × poincarei , as a nothospecies therefore, in support of this view. As discussed below, we largely agree with the arguments that Descoings (2005a) raised in support of treating K. × poincarei as a hybrid, and present additional information (asterisked in the enumeration below) in support of this view:

1. Kalanchoe × poincarei shares the climbing habit of species here included in K. ser. Vilana and, like K. × rechingeri , has some morphological features that facilitate a climbing habit. These include recurved leaf apices and rather thin, twining stems. *However, like K. × rechingeri (see below), K. × poincarei lacks the internodal spinule unique to species of K. ser. Vilana and its stems have a greater diameter ( Figs 1 , 4 , 5 ).

2. Kalanchoe × poincarei shows considerable variation in the shape of its leaves, as also observed in K. beauverdii , with phases of more distinctly petiolate, ovate leaves with entirely dentate margins, alternating, especially when flowering approaches, with phases of less petiolate, lanceolate-sublinear leaves, with few-toothed margins.

3. Kalanchoe × poincarei (and K. × rechingeri , see below) bear specialised pedestals on which bulbils are carried on the leaf margins ( Fig. 5A ). This trait is rare in Kalanchoe , absent in the species included in K. ser. Vilana, and only present in K. tubiflora , K. daigremontiana , K. laetivirens , K. sanctula , some forms historically attributed to K. rosei (but not the autonymic variety), as well as in the nothospecies K. × houghtonii and K. × richaudii. *Of these taxa, only K. tubiflora , K. daigremontiana , some forms of K. rosei , and K. × houghtonii, which may occur naturally or as an introduction to southwestern Madagascar, are partially sympatric with K. × poincarei .

4. The shape and succulent nature of the calyx of K. × poincarei is similar to that of K. beauverdii . *Furthermore, both taxa bear a calyx that is not fused for most of its length, with the tube wider than long, unlike K. scandens , K. costantinii , and K. × rechingeri ( Figs 2 , 5 ).

5. * Descoings (2005a: 3–9) notes that under his broad concept of K. beauverdii ( Descoings 2003: 147) , which results in a wide range of corolla morphologies recognised for the species, that K. × poincarei also falls in this range. However, this is not supported by our work. Unlike the species included in K. ser. Vilana, the flowers of K. × poincarei are pink-purple, not brown-blue, and display a far less flared corolla. Only a few species in K. sect. Invasores share this pink-purple flower colour, namely K. daigremontiana , K. laetivirens , K. sanctula , K. peltigera , as well as some forms of K. tubiflora , K. rosei and K. × houghtonii. A more constricted, less flared corolla, is common to all representitives of K. subg. Bryophyllum , except in the species of K. ser. Vilana ( Fig. 6 ).

6. The nectar scales of K. × poincarei are wider than long, as in the species of K. ser. Vilana. *In fact, among representitives of K. sect. Invasores, only K. tubiflora , K. rosei , and a few other species not sympatric with K. × poincarei bear the opposite state, i.e. nectar scales as long as wide or slightly longer.

7. Kalanchoe × poincarei bears isodiametric pedicels and non-stipitate corollae as do species of K. ser. Vilana. *Importantly, the flowers of K. tubiflora , K. daigremontiana , K. laetivirens , K. sanctula , and K. × houghtonii are also non-stipitate, while those of most forms of K. rosei are.

8. *Of the species of K. ser. Vilana recognised in this study, only K. beauverdii is sympatric with K. × poincarei .

If Descoings (2005a) is to be followed, as we do here, regarding his treatment of K. × poincarei as a nothospecies, the most likely parentage, based on the analysis presented above, involves K. beauverdii and K. daigremontiana . We agree with Descoings (2005a) that K. tubiflora is an unlikely parent, based on its typically orange-red flower colour, petiole maculation, leaf shape, and nectar scale morphology. However, it is conceivable that the other parent of K. × poincarei , apart from K. beauverdii , involves K. × houghtonii or a form of K. rosei , excluding the autonymic one.

Finally, the possibility that K. × poincarei is not a hybrid, but instead represents an intermediate stage of adaption to the climbing habit between K. ser. Vilana and the rest of K. sect. Invasores cannot be entirely excluded.

Other material determined by Descoings (2005a: 9) as representing K. × poincarei (P-P00444058 to P-P00444061) that originated from the Botanical Garden of Tananarive, differs significantly from the type, specifically by having a longer calyx tube, in having sessile leaves, in lacking fully and deeply dentate leaf margins, and by having red rather than pink-purple flowers ( Fig. 5B ). Based on these traits, those plants seem to belong to K. × rechingeri , or a similar hybrid, instead (see ‘Identification key’, under ‘Inter-series natural hybrids involving climbing kalanchoes’). Therefore, K. × poincarei is so far only known from a single specimen and was never seen in cultivation or rediscovered in the wild.

Figures

FIGURE 1. Comparison of leaves and stems of representatives of Kalanchoe ser. Vilana, not to scale. A. K. costantinii var. unguifera (R. Shtein 957). B. K. costantinii var. costantinii (R. Shtein 901). C. K. beauverdii (R. Shtein 391, epitype). D. K. beauverdii var. pertinax (G.F. Smith 1126, type). E. K. beauverdii var. juelii (R. Shtein 361). F. K. beauverdii var. juelii (R. Shtein 921). G. K. guignardii var. schistosepala (R. Shtein 212, type). H. K. scandens (R. Shtein 818). I. K. ×rechingeri (R. Shtein 148). Plants cultivated in Israel and South Africa. Photograph credits: all Ronen Shtein, except D, Gideon F. Smith.

FIGURE 2. Comparison of the flowers of representatives of Kalanchoe ser. Vilana, to scale. A. K. costantinii var. unguifera (R. Shtein 957). B. K. costantinii var. costantinii (R. Shtein 901). C. K. beauverdii var.juelii (R. Shtein 921). D. K. beauverdii (R. Shtein 391, epitype). E. K. beauverdii var. pertinax (G.F. Smith 1126, type). F. K. scandens. G. K. guignardii var. schistosepala (R. Shtein 212, type). Plants cultivated in Israel, Italy, and South Africa. Photograph credits: A, B, D, G, Ronen Shtein; C, Patrizia Simbola; E, F, Gideon F. Smith.

FIGURE 4. Comparison of selected characters of representatives of Kalanchoe ser. Vilana, to scale, based on preserved material held at Herb. P. A. Type of K. costantinii var. unguifera, A1 flowers and A2 leaves. B. Epitype of K. costantinii var.costantinii, B1 flowers and B2 leaves. C. Syntype of K. scandens (P-P00374193), C1 flowers and C2 leaves. D. Type of K. beauverdii var. juelii, D1 buds and D2 leaves. E. Type of K. guignardii, E1 flowers and E2 leaves. F. Material referable to K. guignardii var. schistosepala (P-P00431145), flowers. G. Lectotype of K. beauverdii var. beauverdii, flowers. Photograph credits: all Herb. P.

FIGURE 5. Inter-series natural hybrids involving climbing kalanchoes. A. Type of K. ×poincarei at Herb P. B. Material previously determined as K. ×poincarei at Herb P (P-P00444059). C. A specimen of K. ×rechingeri at Vienna (W 1954-0007470). D, E, F. K. ×rechingeri (R. Shtein 148) in flower and in bud, cultivated in Israel. Elements A–C to scale. Photograph credits: A–B, Herb. P; C, Herb. W; D–F, Ronen Shtein.

FIGURE 6. Corolla segments viewed from the mouth (i.e., from below) of selected representatives of Kalanchoe ser. Vilana. A. K. beauverdii (R. Shtein 391, epitype). B. K. guignardii var. schistosepala (R. Shtein 212, type). C. K. costantinii var. unguifera (R. Shtein 957). D. K. costantinii var. costantinii (R. Shtein 901). Not to scale, grid segment in each element represents 5 mm. All photographs by R. Shtein.

FIGURE 7. Geographical distribution ranges of representatives of Kalanchoe ser. Vilana recognised in this study. The precise localities of the types of K. schizophylla, K. beauverdii var. beauverdii, K. beauverdii var. pertinax, and K. costantinii var. costantinii in Madagascar are insufficiently known to be placed (see text for details).