Ecology

Agent-resource affiliation networksWe consider games involving populations of agents that extract from multiple common-pool sources (which term we use for nodes representing resources in accord with previous related work15,16). Agents’ access to sources is defined by bipartite networks, wherein a link between an agent and a source indicates that the agent can access that source. This access is determined by some exogenous factors and remains fixed in time. The set of agents affiliated with a particular source (s) is denoted as ({mathbf{A}}_{s}), while the set of sources affiliated with a particular agent (a) is denoted as ({mathbf{S}}_{a}). The degree of an agent (a) is denoted by (m(a)), and the degree of a source (s) by (n(s)).To explore the effects of network topology upon extraction dynamics and wealth distributions, we generate ensembles of ({10}^{3}) networks, each having (50) agents and (50) sources and sharing mean agent degree (langle mrangle =5) and mean source degree (langle nrangle =5). All networks thus share the same total numbers of agents, sources, and links, but differ in how these links are distributed among agents and sources. We generate 9 network ensembles, each generated to represent a particular combination of one of three types of degree heterogeneity in its source degree distribution (U: uniform-degree, L: low-heterogeneity, or H: high-heterogeneity) with one of three similar distributions of agent degree (u, l, or h39) (Supplementary Information S1.1). Degree histograms, averaged over each ensemble, provide a representative source degree distribution ({P}_{mathbf{S}}(n)) and agent degree distribution ({P}_{mathbf{A}}(m)) for each network type (Fig. 2a and b). It is worth noting that the results of the simulations depend primarily on the degree distributions of agents and sources rather than on the overall size of the networks used (Supplementary Information S3.1).Figure 2(a) Source degree distributions and (b) Agent degree distributions for 9 network ensembles, each representing a combination of a Uniform-degree (U), Low-heterogeneity (L), or High-heterogeneity (H) source degree distribution with a uniform-degree (u), low-heterogeneity (l), or high-heterogeneity (h) agent degree distribution. Ensemble mean time-averaged quantities from pure free adaptation dynamics: (c) Agent payoffs (f(a)) as a function of agent degree (m(a)); (d) Collective extraction (overrightarrow{q}(s)) as a function of source degree (n(s)); (e) Source quality (b(s)) as a function of source degree (n(s)); and (f) Period of oscillation (T(s)) as a function of source degree (n(s)). Means are computed from simulations on ({10}^{3}) networks of each type.Full size imageNetworked CPR extraction gameOn these networks, we simulate iterative games in which agents vary the extraction effort that they apply to their affiliated sources, altering the quality of these sources; in turn, these changes in source quality then influence how agents adapt their extraction levels in subsequent rounds. The extraction effort exerted by agent (a) upon its affiliated source (s) is denoted as (q(a,s)). The total effort exerted by an agent (a), its individual extraction, is denoted by (overleftarrow{q}left(aright)=sum_{sin {mathbf{S}}_{a}}q(a,s)). The total effort exerted upon source (s), or its collective extraction, is denoted by (overrightarrow{q}left(sright)=sum_{ain {mathbf{A}}_{s}}q(a,s)). The quality of a source (s) is quantified by the benefit (b(s)) per unit extraction effort applied that the source provides. The cost associated with extraction is given by a convex (quadratic) function of (overleftarrow{q}left(aright)), such that marginal costs increase with individual extraction15,16. In addition to modelling the increasing costs (i.e., diminishing returns) associated with the physical act of extraction itself, this could also reflect escalating, informal social penalties that result from increasing extraction (i.e., “graduated sanctions”1,40). The net payoff accumulated by an agent (a) in a game iteration is thus$$fleft( a right) = left[ {mathop sum limits_{{s in {mathbf{S}}_{a} }} qleft( {a,s} right) cdot bleft( s right)} right] – frac{gamma }{2}{ }mathop{q}limits^{leftarrow} left( a right)^{2} ,$$
(1)

where (gamma) is a positive cost parameter.Bistable model of CPR depletion and remediationSources are bistable, meaning that at any time they can occupy one of two states: (1) a viable state, during which the source provides a benefit of magnitude (alpha) in return for each unit of extraction effort, and (2) a depleted state, during which this benefit is reduced by (beta) ((0 vec{q}_{{text{D}}} left( s right)} \ {0, } & {{text{if }} chi_{t – 1} left( s right) = 1{text{ and }}vec{q}_{t} left( s right) le vec{q}_{R} left( s right)} \ {chi_{t – 1} left( s right),} & {text{otherwise }} \ end{array} } right.$$
(3)
In the results that follow, we focus upon a uniform capacity scenario, wherein all sources share identical threshold values (vec{q}_{{text{D}}} left( s right) equiv vec{q}_{{text{D}}}) and (vec{q}_{{text{R}}} left( s right) equiv vec{q}_{{text{R}}} left( s right)). An alternative degree-proportional capacity scenario, in which threshold values increase with source degree, is discussed in the Supplementary Information (S3.4.2).Free adaptationUnder the free adaptation strategy, an agent updates its extraction levels independently at each of its affiliated sources depending on the state of each (Fig. 1b). As in the replicator rule often applied in networked evolutionary game models17,41,42, the rate at which an agent adapts its extraction levels within a time interval ({Delta }t) is proportional to the marginal payoff that the agent expects to attain thereby:$$frac{{{Delta }qleft( {a,s} right)}}{{{Delta }t}} = kfrac{partial fleft( a right)}{{partial qleft( {a,s} right)}},$$
(4)
where (k) is a rate constant. So, each extraction level (qleft( {a,s} right)) is updated according to$$q_{t + 1} left( {a,s} right) = q_{t} left( {a,s} right) + kleft[ {alpha – beta chi_{t} left( s right) – gamma {mathop{q}limits^{leftarrow}}_{t} left( a right)} right].$$
(5)
The higher an agent’s individual extraction (overleftarrow{q}(a)), the more slowly it will increase its extraction from viable sources, and the more rapidly it will reduce its extraction from depleted sources.Uniform adaptationWhen applying the uniform adaptation strategy, an agent adjusts each of its extraction levels by the same magnitude (Delta qleft(a,sright)equivDelta overleftarrow{q}(a)/mleft(aright)) (Fig. 1c). Assuming again that the rate at which an agent enacts this update is proportional to the associated marginal payoff, an agent adapts its extraction levels at all of its affiliated sources (s) by$$q_{t + 1} left( {a,s} right) = q_{t} left( {a,s} right) + kleft[ {alpha – beta overline{chi }left( a right) – gamma {mathop{q}limits^{leftarrow}}_{t} left( a right)} right],$$
(6)
where (overline{chi }left( a right) = left[ {mathop sum nolimits_{{s^{prime} in {mathbf{S}}_{a} }} chi left( {s^{prime}} right)} right]/mleft( a right)) is the mean state of the agent’s affiliated sources.ReallocationWhen practicing reallocation, an agent shifts an increment of extraction effort from a depleted source to a viable source such that its overall individual extraction (mathop{q}limits^{leftarrow} left( a right)) remains unchanged (Fig. 1d). The agent thus randomly selects one depleted source (s_{{text{D}}} in {mathbf{S}}_{a}) and one viable source (s_{{text{V}}} in {mathbf{S}}_{a}), if available. Since the marginal payoff per unit reallocated is (beta), updates its extraction levels such that$$q_{t + 1} left( {a,s} right) = left{ {begin{array}{*{20}c} {q_{t} left( {a,s} right) – kbeta , } & {{text{if}} s = s_{{text{D}}} } \ {q_{t} left( {a,s} right) + kbeta , } & {{text{if}} s = s_{{text{V}}} } \ {q_{t} left( {a,s} right),} & {text{otherwise }} \ end{array} } right.$$
(7)

When an agent’s affiliated sources all share the same quality value, no such reallocation is possible, and so the agent retains its present extraction levels: (q_{t + 1} left( {a,s} right) = q_{t} left( {a,s} right)) for all (s in {mathbf{S}}_{a}).Mixed strategiesAn agent’s adaptation strategy (({p}_{0},{p}_{updownarrow },{p}_{leftrightarrow })) comprises the probabilities that it will practice each of these update rules in any given round: its free adaptation propensity (({p}_{0})), its uniform adaptation propensity (({p}_{updownarrow })), and its reallocation propensity (({p}_{leftrightarrow })). An agent’s choice of a particular update rule is thus based only on its own innate inclinations, but the rate at which it enacts the selected rule is influenced by current resource conditions. We first simulate dynamics in which the same adaptation strategy is shared by all members of a population throughout the entire course of a simulation. We then consider games in which agents’ individual adaptation strategies are each allowed to independently evolve under generalized reinforcement learning38,43 (Supplementary Information S1.3.4). That is, after enacting a chosen update rule in an iteration (t), each agent (a) observes the payoff change (Delta {f}_{t}left(aright)={f}_{t}left(aright)-{f}_{t-1}(a)). If (Delta {f}_{t}left(aright) >0), then the agent’s relative propensity to practice this update rule in subsequent rounds is increased. If the agent’s payoffs decreased ((Delta {f}_{t}left(aright)0) or remediation threshold ({overrightarrow{q}}_{mathrm{R}}left(sright)). That is, all resource depletion events are assumed to be extreme enough to motivate agents to continuously “self-regulate” by remediating depleted sources (see Supplementary Information S5 for a more thorough discussion of these parameter settings).In simulations where reinforcement learning is applied, all agents are initialized with ({p}_{updownarrow }={p}_{leftrightarrow }=.333). For pure free adaptation simulations (({p}_{0}=1)), initial extraction levels were randomized (({q}_{t=0}left(a,sright)in [0,frac{{overrightarrow{q}}_{mathrm{D}}left(sright)}{nleft(sright)}])). All other simulations (({p}_{0} More

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Reproductive successThe production of urinary pheromones correlated with male but not female reproductive success (RS; defined in “Materials and methods” section). The most important predictors of male RS were total urinary protein concentration (75%) and social status (69%; Table 1; based on conditional model average sum of weights). The relative importance of age, creatinine, and mass ranged from 23 to 39%; PC ratio (protein:creatinine concentration) was excluded from the model due to collinearity (VIF = 6.97). Total urinary protein concentration during the enclosure phase was positively correlated with RS for males (Spearman R = 0.52, p = 0.01; Fig. 1a), but not females (Fig. 1b). This correlation is explained by the low protein concentration in the urine of non-reproductive males, as it is no longer significant after removing these males from the analysis (R = 0.12, p = 0.62; Supplementary Fig. S2). The median total urinary protein concentration was 5512 µg mL−1 and 5028 µg mL−1 for reproductive and non-reproductive males, respectively (Wilcoxon rank sum test W = 5, p  More

Generic nameRavenala Adans.1 (1763: 67). (equiv) Urania Schreb.22 (1789: 212). –Ravenala Scop.23, nom. illeg. (1777: 96) as “Ravenalla Adans”.Type species Ravenala madagascariensis Sonn.24.Note: Dorr & Parkinson25 proposed to conserve the spelling Ravenala Scop. (and correct Scopoli’s original orthography “Ravenalla”) against Ravenala Adans. on the basis that Adanson’s generic names (using a uninominal nomenclature for species) were invalid. Brummitt26 rejected this proposal and considered that Adanson’s generic names were valid27 and thus that there was no need to use Scopoli’s Ravenala (Ravenalla). Moreover, the exact wording in Scopoli23 (1777: 96) is “Ravenalla Adans.”, citing Adanson explicitly, but with an incorrect spelling for the generic name (the double “l”).Typification and emended descriptionRavenala madagascariensis Sonn. (1782: 2[ed. qto.]: 223, tt. 124–126).(equiv) Ravenala madagascariensis J.F.Gmel.28 (1791: 567). (equiv) Urania madagascariensis (Sonn.) Schreb. ex Forsyth f.29 (1794: 212). (equiv) Heliconia ravenala Willemet30 (1796: 22). (equiv) Urania speciosa Willdenow31 (1799: 7). (equiv) Urania ravenalia (Willemet) A.Rich.32 (1831: 19). –Ravenala madagascariensis Adans.1 (1763: 597), nomen invalid., appearing on page 597, abbreviated in the final index of Adanson’s book as “Ravenala madag. 67”, which can also be construed as referring to Madagascar as a locality.Type Lectotype, here designated: The plate numbered 126, representing the typical lax mature infructescence, in Sonnerat24 (1782: plate 126). Epitype, here designated: MADAGASCAR (bullet) Fort-Dauphin, Forêt de Manantantely, [24°58′ 59.988″S, 46°55′0.012″E, calc. from label], 60–300 m elev., 15 September 1928, H. Humbert 5730 (Epitype: MNHN-P-P02234599!, Isoepitypes: MNHN-P-P02234602!, MNHN-P-P02234604!, MNHN-P-P02234605!).Additional specimen examined: MADAGASCAR (bullet) Toamasina: Foulpointe, Analalava Forest, plant growing close to the main forest station, 17°42.3′S, 49°27.38′E, 50 m elev., 20 March 2016, T.Haevermans, M. Vorontsova, S. Dransfield & J. Razanatsoa 821 (TAN!, P!, K !) (bullet) X. Aubriot et al. 45 (P00696168!, P00696167!, P00685124!, TAN!) (bullet) Along Route #5 from Fenerive to Maroantsetra, disturbed areas along road, 100 m elev., 28 February 1975, T. B. Croat 32540 (L-WAG.1111446!, L-WAG.1111447!, MO-358490!, MO-358491!, MO-358523!) (bullet) Toalagnaro, Ebakika, District de Fort-Dauphin, 12 July 1932, R. Decary 10107 (P02234596!) (bullet) Vondrozo (commune de Farafangana), 16 September 1926, R. Decary 5428 (P02234588!, P02234591!, P02234592!) (bullet) 2 km E of Ranomafana towards Brickaville, 18.965° S, 48.8564° E, 4 March 1992, J. Kress et al. 92-3412 (US00424302!, US00424299!, US00424300!, US00424301!, US00424303!) (bullet) 18 km E of Ranomafana, 25 km W of Brickaville, 18.9453° S, 48.9664° E, 4 March 1992, J. Kress et al. 92-3414 (US00424312!, US00424309!, US00424310!, US00424311!, US00424313!). MAURITIUS (bullet) Isle de France, s.dat., Commerson s.n. (P02234587!, P-JU!, P-LAM!).Identity of Ravenala madagascariensis Sonn. —Figs. 2d, 3d, 4d, 5d— In the absence of a specimen undoubtedly collected or seen by Sonnerat (Commerson’s specimens, collected in Mauritius and preserved in both Jussieu’s and Lamarck’s herbaria at the Paris herbarium (P-JU and P-LAM), might actually be part of original material), we decided to lectotypify from plates 124, 125 and 126 of the protologue in Sonnerat’s valid publication24 of the species. On page 225, Sonnerat24 mentions that the plant originated from Madagascar but was transported and established in Mauritius (known at the time as Isle de France) at the “Jardin des Pamplemousses”. We observed plants growing in this garden as well as naturalized plants occurring in the wild in Mauritius; all the plants we saw suckered and possessed the characteristic pointed conical fruits also observed in the Fort-Dauphin population. Sonnerat also specified that the original plant grew in marshy areas, which corresponds exactly to the coastal populations that can be found on the eastern coast of Madagascar (i.e. the “Horonorona” variant of Blanc et al.13). Plate 126 shows the typical mature infructescence of the species, with the space between bracts increasing before releasing the seeds (unlike other species of Ravenala). However, the “tree” pictured on plate 124 is a non-suckering plant, which in our opinion can be explained as artistic license on the part of the illustrator, as all the plants observed in Mauritius consistently sucker, like the plants growing in the south-eastern marshy areas. We also decided to designate an epitype with a documented locality in Madagascar (the material in P-JU and P-LAM does not bear a precise indication of locality) to fix the application of the name R. madagascariensis to the populations occurring in the marshy areas surrounding Fort-Dauphin, where only one morphotype is known.Figure 3Comparison of petiole bases. (a) R. agatheae. (b) R. blancii. (c) R. grandis. (d) R. madagascariensis. (e) R. menahirana. (f) R. hladikorum. Photographs Thomas Haevermans©.Full size imageFigure 4Comparison of inflorescences. (a) R. agatheae. (b) R. blancii. (c) R. grandis. (d) R. madagascariensis. (e) R. menahirana. (f) R. hladikorum. Photographs Thomas Haevermans©.Full size imageFigure 5Species of Ravenala in their natural habitat. (a) R. agatheae. (b) R. blancii. (c) R. grandis. (d) R. madagascariensis. (e) R. menahirana. (f) R. hladikorum. Photographs Thomas Haevermans©.Full size imageEmended description Plants suckering, 6–12 meters tall (adult), trunk circumference (d.b.h.) 20–30 cm, juvenile and adult laminae distributed in a perfect fan, 14–25 leaves simultaneously alive on the adult plant, 1–3 leaves between inflorescences. Leaves adult petiole 380–440 cm long, greenish-yellow, slightly waxy, sheath margin undeveloped to moderately developed (0–9 mm), entire, not drying, slightly splitting when aged (Fig. 3d), petiole/lamina ratio 1.9–(2.2)–2.3, adult lamina (200 times 100) cm, light green, juvenile lamina base non-decurrent. Inflorescences 4–6 live lateral inflorescences at a time, (100 times 100) cm (peduncle excluded), 8–16 bracts per inflorescence, bracts 200–(450 times 50)–100 mm, with some wax to very waxy, margin uniformly green (Fig. 4d), cincinnii of ca. 10 flowers per bract, flowering sequentially, bracteoles without a colored stripe. Flowers 240–280 mm long (ovary included), inferior ovary 40–50 mm long, perianth yellowish, sepals narrowly triangular 240–250 (times 10)–12 mm, sheathing (fused) petals narrowly triangular 220–230(times)ca. 10 mm, free petal acicular 180–190 (times 5) mm, slightly smaller than the remaining perianth with mean free petal/mean fused petal length ratio = 0.8, petal blotches absent, stamens (roughly) the same size as the perianth, 200–210 mm long, style 200–230 mm long, stigma 15–20 mm long, oblong ovoid with a basal constriction. Infructescences lax (bract bases not imbricate at maturity), stiff and coriaceous persisting bracts, old infructescences deciduous, 4–8 fruits per bract. Fruits 70–120 (times 30)–35 mm, trilocular septifragal capsule, apices conical (Fig. 2d), seeds 6–(8.5)–(11 times 5)–(6.4)–8 mm, shiny, dark brown, mostly globose, varying in shape according to their distribution in the capsule, ultramarine blue aril.Ecology Ravenala madagascariensis is a low-altitude species restricted to swampy areas of the eastern coast of Madagascar. Populations outside of Madagascar on nearby islands are reputedly non-indigenous24.Preliminary IUCN assessments We propose a Least Concern status for R. madagascariensis, having an E.O.O ( > 20,000) km2 and an A.O.O. ( > 2,000) km2 (criterion B)33.Note This emended description for R. madagascariensis was drawn up from our own observations and collections, and was made comparable point by point to the descriptions of the five new species presented below, along with a dichotomous identification key to all six species.New species descriptions
Ravenala agatheae Haev. & Razanats. sp. nov.—Figs. 2a, 3a, 4a, 5a, 6
Type MADAGASCAR (bullet) Antsiranana: Ambanja District, along R.N.6 road to Ankaramibe, 13°45′54.8″S, 48°21′27.7″E, 30 m elev., on degraded lateritic slopes, 28 October 2018, T. Haevermans, A. Haevermans & J. Razanatsoa 830 (Holotype: TAN!, Isotypes: K!, MO!, P!).Figure 6Ravenala agatheae. (a) young infructescence. (b) adult plant habit showing the suckers at the base and the persistent petioles and old infructescences. (c) fruit with a conical apex. (d) infructescence with remains of dried flowers and dried bracts. (e) style apex. (f) inflorescence with open flowers. (g) open flower. Ink drawings on (75 , upmu) polyester tracing paper by Agathe Haevermans© from specimen Haevermans et al. 830, and observations in-situ.Full size imageParatypes MADAGASCAR (bullet) Antsiranana: 57–58 km N of Ambanja, 13°22′59.9″S, 48°48′E, 22 May 1974, A.H. Gentry 11878 (L-WAG.1111448!, L-WAG.1111449!, MO-358489!, TAN) (bullet) Ampasindava, forêts d’Ambilanivy et Rangoty, 13°48′36″S, 48°10′48″E, 29 November 2007, L. Nusbaumer 2658 (G334213/1!, MO!, TAN) (bullet) Mahajanga: Morafenobe, Beravy, 15 km from Beravy, near the road from Orombato to Beravy, 18°3′50″S, 44°31′46″E, 09 June 2016, F. Rakotonasolo et al. 2772 (K, P00782931!, TAN).Diagnosis Similar to Ravenala madagascariensis but differs in its dark green narrower laminae, tricolor petioles with very developed dryish petiole sheath margins, very waxy petioles, the persistence of older infructescences for several years, a purple stripe on the bract margin, longer bracts, a whitish perianth, brown blotches on its mature fused petals, the bracteole apex tinged with pink, an ovoid pointed stigma, dense infructescences, smaller inflorescences, the free petal much shorter than the fused petals, and an end of year flowering period.Distribution Plants restricted to Madagascar, growing in the north-western part of the island. We observed it growing from the southern part of the Diego Suarez area (on the hills along the road leading to Tsingy Rouge and the city of Sadjoavato) in the north to the western part of the Mahajanga province down to the Melaky region, with most observations around Ambanja34. We also observed that the species was cultivated on Nosy Be.Preliminary IUCN assessments We propose a Least Concern status for R. agatheae, having an E.O.O ( > 20,000) km2 and an A.O.O. ( > 2,000) km2 (criterion B)33.Ecology This species is adapted to seasonally dry and warm coastal habitats, growing on slopes at low elevations in north-western coastal areas of Madagascar, from Antsiranana (Diego-Suarez) down to the Melaky region in the Mahajanga province.Etymology This species is named after to the first author’s wife, Agathe Haevermans, a botanical illustrator at the Muséum National d’Histoire Naturelle, who helped discover this species in the field with the collecting team and who contributes greatly to botany by producing illustrations of new taxa from biodiversity hotspots such as Madagascar.Description Plants suckering, 6–10 meters tall (adult), trunk circumference (d.b.h.) 20–30 cm, juvenile and adult laminae distributed like a regular fan, 9–22 leaves simultaneously alive on the adult plant, 1–3 leaves between inflorescences. Leaves adult petiole 300–460 cm long, tricolor (dark green with a waxy white strip and red petiole sheath margin subsequently drying out, Fig. 3a), very waxy, sheath margin very developed (10 mm and more), entire, dryish-papyraceous and protruding at 90 degrees, petiole/lamina ratio 1.7–(1.95)–2.2, adult lamina 174–(210 times 72)–86 cm, dark green, juvenile lamina base non-decurrent. Inflorescences 4–6 live lateral inflorescences at a time, 70–(90 times 90)–100 cm (peduncle excluded), 10–14 bracts per inflorescence, bracts 450–500 (times 80)– 90 mm, with some waxiness (Fig. 4a), margin bearing a purple stripe, cincinnii of 8–10 flowers per bract, flowering sequentially, some pink tinge at the apex of bracteoles. Flowers 260–310 mm long (ovary included), inferior ovary 40–60 mm long, perianth whitish, sepals narrowly triangular 220–250(times)ca. 10 mm, sheathing (fused) petals narrowly triangular 200–(220times)ca. 10 mm, free petal acicular 130–(140 times 5) mm, much smaller than the remaining perianth with a mean free petal / mean fused petal length ratio = 0.6, petal blotches present, stamens (roughly) the same size as the perianth, 210–220 mm long, style 220 mm long, stigma 15 mm long, ovoid-pointed with basal constriction. Infructescences compact (bracts bases imbricate at all stages of maturity), stiff and coriaceous persisting bracts on mature infructescence, persistence of old infructescences, 4–10 fruits per bract. Fruits 90–110 (times) 30–45 mm, trilocular septifragal capsule, apices conical (Fig. 2a), seeds shiny, dark brown, mostly globose, varying in shape according to their distribution in the capsule, ultramarine blue aril.
Ravenala blancii Haev., V. Jeannoda & A. Hladik sp. nov. —Figs. 2b, 3b, 4b, 5b, 7
Type MADAGASCAR (bullet) Andasibe; 18°56′00″S, 48°25′06″E; 940 m elev.; 01 December 2002; A. Hladik & C.-M. Hladik 6760 (Holotype: TAN!, Isotypes: K!, MO!, P!).Paratypes MADAGASCAR (bullet) Andasibe; 18°56′00″S, 48°25′06″E; 940 m elev., 23 Aug. 1998, A. Hladik & al. 6239 (P!, fruits) (bullet) June 2001, A. Hladik & al. 6650 (P!, leaves, fruits, bracts) (bullet) Andasibe-Mantadia area, Vakôna, Kalonora; 18°53′17.3″S, 48°25′51.3″E, 08 November 2018, 934 m elev., T. Haevermans & al. 832 (K!, MO!, P!, TAN!).Diagnosis Similar to Ravenala madagascariensis but differs in its non-suckering habit, decurrent juvenile lamina bases, toroidal distribution of juvenile laminae, smaller number of leaves simultaneously alive on the adult plant, dark green lamina and green non waxy petiole, smaller leaves, smaller number of live inflorescences, smaller number of bracts in an inflorescence, non-waxy bracts, sub-simultaneous flowering, smaller flowers, smaller inflorescences, non-persistence of entire bracts on dry infructescences, October/November flowering period.Distribution Andasibe-Mantadia, Ranomafana21. Restricted to Madagascar.Preliminary IUCN assessments We propose a Data Deficient status for R. blancii; further fieldwork is required to understand its precise distribution and the status of its populations33.Ecology High-elevation species found in eastern rainforests at elevations between 600 and 1,100 m. The species seems to favor cool tropical humid and shady conditions.Etymology This species is named after Dr. Patrick Blanc, world renowned botanist, plant ecologist and street artist, inventor of the planted vertical walls known as “Mur Végétal” and who first recognized the sheer originality of the juvenile phases of this peculiar taxon.Description Plants solitary (never suckering), 10–15 meters tall (adult), trunk circumference (d.b.h.) 20–30 cm, juvenile laminae distributed in a toroidal shape, adult laminae arranged in a regular fan, 9–16 leaves simultaneously alive on the adult plant, 2–4 leaves between inflorescences. Leaves adult petiole 240–310 cm long, green, not waxy, sheath margin undeveloped, entire, not drying, smooth with a worn-out irregular aspect (Fig. 3b), petiole/lamina ratio 1.8–(2.0)–2.2, adult lamina 120–160 (times) 90–104 cm, dark green, juvenile lamina base decurrent. Inflorescences 2–3 live lateral inflorescences at a time, (60 times 70) cm (peduncle excluded), 4–6 bracts per inflorescence, bracts 160–350 (times) 50–90 mm, no waxiness (Fig. 4b), margin color uniformly green, cincinnii of 5–14 flowers per bract, flowering sub-simultaneously, bracteoles sometimes pink colored. Flowers 165–280 mm long (ovary included), inferior ovary 40–50 mm long, perianth whitish-yellowish, sepals narrowly triangular 125–231 (times) 10–12 mm, sheathing (fused) petals narrowly triangular 105–190 (times 10) mm, free petal acicular 105–178 (times 3)–5 mm, free petal and fused petals of sub-equal size with a mean free petal / mean fused petal length ratio = 1.0, petal blotches absent or present, stamens (roughly) the same size as the perianth, 115–186 mm long, style 132–220 mm long, stigma 20-25 mm long, ovoid to ovoid-pointed with a basal constriction. Infructescences compact (bract bases imbricate at all stages of maturity), torn and degraded bracts on mature infructescence, old infructescences deciduous, 5–14 fruits per bract. Fruits 80–120 (times) 32–45 mm, trilocular septifragal capsule, apices conical (Fig. 2b), seeds 6–10 (times) 3.2–6 mm, shiny, dark brown, mostly globose, varying in shape according to their distribution in the capsule, ultramarine blue aril.Note The strong leaf dimorphism between juvenile and adult forms is characteristic of this species13, a phenomenon which is not present in the other taxa. The base of the juvenile plant usually grows buried in the leaf litter due to the action of traction roots13, its decurrent leaves (Fig. 7) giving it the aspect of a bird’s nest fern.Figure 7Ravenala blancii. (a) juvenile plant habit with roots. (b) juvenile plant showing the arrangement of laminae. (c) adult plant habit. (d) mature infructescence segment. (e) juvenile leaf showing the attenuate base of the lamina. (f) inflorescence with sub-simultaneous opening of the flowers. (g) young infructescence with already degraded bracts. (h) seeds with arilla. (i) open flower. (j) details of the stigma. (k) style. Ink drawings on (75 , upmu) polyester tracing paper by Agathe Haevermans© from specimens Hladik 6790, 6239, 6650, Haevermans et al. 832, and observations in-situ.Full size image
Ravenala grandis Haev., Razanats., A. Hladik & P. Blanc sp. nov.—Figs. 2c, 3c, 4c, 5cType. MADAGASCAR (bullet) Ampasimbe Commune, Maromaniry Fokontany, along Route Nationale, 18°57′41.8″S, 48°42′41.4″E, 258 m elev., 08 November 2018, T. Haevermans, A. Haevermans & J. Razanatsoa 831 (Holotype: TAN!, Isotypes: K!, MO!, P!).Paratypes MADAGASCAR (bullet) Varifoana, près d’Ambohimahasoa-sud, 15 May 1964, R. Capuron 26014SF (P02234597!) (bullet) Soanierana-Antasibe[Andasibe], 350 m elev., 10 December 1938, H.J. Lam & A.D.J. Meeuse 5867 (L-WAG.1111450!, L-WAG.1111451!, L-WAG.1111452!, L-WAG.1111453!, L-L.1477714!, L-L.1477715!).Diagnosis Similar to Ravenala madagascariensis but differs in its non-suckering habit, much larger dimensions, very thick leathery laminae, very waxy dark green-yellowish petioles, much larger bracts and overall dimensions, whitish/pure white perianth, strong reddish-pink stripes on its bracteoles, cylindrical stigma without basal constriction, stamens much shorter than perianth, and fruit with a truncated apex.Distribution Eastern rainforests at around 200–500 m elevation in Madagascar13,20.Preliminary IUCN assessments We propose a Data Deficient status for R. grandis; further fieldwork is required to understand its precise distribution and the status of its populations33.Ecology This species seems to favor growing in low discontinuous forests on inselbergs12 and thrives in secondary degraded vegetation on the slopes of eastern rain forests.Etymology The name of this species is in reference to its stature and habit, the most robust species of Ravenala known.Description Plants solitary (never suckering), 20–30 meters tall (adult), trunk circumference (d.b.h.) 30 cm, juvenile and adult laminae distributed in a perfect fan, 15–30 leaves simultaneously alive on the adult plant, usually 3 leaves between inflorescences. Leaves adult petiole 390–440 cm long, dark green/light green-yellowish, very waxy (Fig. 3c), sheath margin moderately developed to undeveloped (0–9 mm), entire on young leaves, splitting and dryish when old, petiole/lamina ratio 1.8–(2.2)–2.6, adult lamina 170–230 (times) 94–120 cm, light green, juvenile lamina base non-decurrent. Inflorescences 4–6 live lateral inflorescences at a time, 100–120 (times) 80–100 cm (peduncle excluded), 10–20 bracts per inflorescence, bracts 440–540 (times) 140–170 mm, some waxiness (Fig. 4c), margin color uniformly green, cincinnii of ca. 20 flowers per bract, flowering sequentially, bracteoles with a strong reddish-pink stripe. Flowers 300 mm long (ovary included), inferior ovary 50–70 mm long, perianth whitish/pure white, sepals narrowly triangular 220–240 (times) 10–15 mm, sheathing (fused) petals narrowly triangular 210–220 (times) 10–12 mm, free petal acicular 150–170 (times 3) mm, slightly smaller than the rest of the perianth with a mean free petal / mean fused petal length ratio = 0.8, petal blotches absent, stamens much shorter than the perianth, 180–200 mm long, style 180–210 mm long, stigma 14–16 mm long, oblong without basal constriction (almost indistinguishable from style). Infructescences lax (bract bases not imbricate at some stages of maturity), stiff and coriaceous persisting bracts on mature infructescence, old infructescences deciduous, 5–18 fruits per bract. Fruits 100–120 (times) 35–40 mm, trilocular septifragal capsule, apices truncate (Fig. 2c), seeds shiny, dark brown, mostly globose, varying in shape according to their distribution in the capsule, ultramarine blue aril.Note The leaves of this species are the most robust and tough of all Ravenala species, with a thick leathery texture, making it the material of choice for building roofs35.
Ravenala hladikorum Haev., Razanats., V. Jeannoda & P. Blanc sp. nov. — Figs. 2f, 3f, 4f, 5fType MADAGASCAR (bullet) Andasibe; 18°56′00″S, 48°25′06″E; 940 m elev.; 05 February 2004; A. Hladik & C.-M. Hladik 6842 (Holotype: TAN!, Isotype: P!). Paratypes. MADAGASCAR (bullet) Andasibe; 18°56′00″S, 48°25′06″E; 940 m elev.; 23 August 1998; A. Hladik & al. 6240 (fruit with seeds: P!). (bullet) Andasibe-Mantadia area, Vakôna, Kalonora; 18°53′17.3″S, 48°25′51.3″E; 934 m elev., 08 November 2018; T. Haevermans & al. 833 (TAN!, P!, K!, MO!).Diagnosis Similar to Ravenala madagascariensis but differs in its non-suckering habit, the alternate positioning of its adult laminae, its dark green leaves, non-waxy petioles with their very papyraceous petiole sheath margins, more than 1 cm long, smaller lamina dimensions, smaller number of simultaneously live inflorescences, purple stripe on bracts and on bracteoles, non-waxy inflorescences, smaller inflorescences, dense infructescences, truncated fruit apices, and short flowering period from November to December.Distribution Andasibe, Mantady, Ranomafana21. Restricted to Madagascar.Preliminary IUCN assessments We propose a Data Deficient status for R. hladikorum; further fieldwork is required to understand its precise distribution and the status of its populations33.Ecology High-elevation species found in eastern rainforests at elevations between 600 and 1100 m. The species seems to favor cool tropical humid and shady conditions.Etymology This species is named in honor of Annette and Claude-Marcel Hladik from the Muséum National d’Histoire Naturelle in Paris, who dedicated their lives to the study of Madagascan biodiversity and contributed greatly to the discovery of this species.Description Plants solitary (never suckering), 10–15 meters tall (adult), trunk circumference (d.b.h.) 20–30 cm, juvenile laminae distributed like a fan, adult laminae arranged in an irregular fan, 9–18 leaves simultaneously alive on the adult plant, 1–3 leaves between inflorescences. Leaves adult petiole 280–440 cm long, greenish-yellow, not waxy (Fig. 3f), sheath margin very developed (10 mm and more), split, very papyraceous with min. 1 cm brown dry expansions, petiole/lamina ratio 2.1–(2.42)–2.8, adult lamina 120–160 (times) 102–116 cm, dark green, juvenile lamina base non-decurrent. Inflorescences 2–3 live lateral inflorescences at a time, (60 times 90) cm (peduncle excluded), 4–7 bracts per inflorescence, bracts 150–510 (times) 64–100 mm, no waxiness (Fig. 4f), margin green with a purple stripe, cincinnii of 5–14 flowers per bract, sequentially flowering, bracteoles with a dark purple colored stripe. Flowers 240–320 mm long (ovary included), inferior ovary 40–60 mm long, perianth whitish, sepals narrowly triangular 210–265(times)ca. 10 mm, sheathing (fused) petals narrowly triangular 190–240(times)ca. 10 mm , free petal acicular 135–220 (times) 5 mm, almost the same size as the fused petals with a mean free petal / mean fused petal length ratio = 0.9, petal blotches unknown, stamens (roughly) the same size as the perianth, 170–230 mm long, style 187–250 mm long, stigma 20–25 mm long, ovoid with a basal constriction. Infructescences compact (bract bases imbricate at all stages of maturity), stiff and coriaceous persistent bracts on mature infructescences, old infructescences deciduous, 5–14 fruits per bract. Fruits 82–108 (times) 34–48 mm, trilocular septifragal capsule, apices truncate (Fig. 2f), seeds 4–9 (times) 3–6 mm, shiny, dark brown, mostly globose, varying in shape according to their distribution in the capsule, ultramarine blue aril.
Ravenala menahirana Haev. & Razanats. sp. nov.—Figs. 2e, 3e, 4e, 5eType MADAGASCAR (bullet) Foulpointe, Analalava Forest; 17°42.3′S, 49°27.38′E; 50 m elev.; 20 March 2016; T.Haevermans, M. Vorontsova, S. Dransfield & J. Razanatsoa 826 (Holotype: TAN!, Isotypes: P!, K !, MO!).Diagnosis Similar to Ravenala madagascariensis but differs in its non-suckering habit, the alternate dark green laminae tending not to form a perfect fan (Fig. 5e), dark red petioles with a zigzagging well developed dryish sheath margin, more strongly obovoid laminae, smaller number of simultaneously live inflorescences, smaller inflorescences tinged with red, pure white/whitish perianth, smaller flowers, dense infructescences, the fruit apices truncate with a mucro, and subequal free and fused petals.Distribution Appears to be restricted to the east coast in the area around Analalava-Foulpointe up to the Mananara-Avaratra area. Two human observations from Marojejy (North-East) and Tampolo (Masoala) seem also to be this species. Restricted to Madagascar.Preliminary IUCN assessments We propose a Data Deficient status for R. menahirana; further fieldwork is required to understand its precise distribution and the status of its populations33.Ecology This coastal forest-dwelling species favors low-elevation tropical humid conditions in the Analalava-Foulpointe area, extending north to Mananara-Avaratra area, and maybe up to Marojejy.Etymology The name of this species is in reference to one of its local names “menahirana”, given to the species in the Analalava-Foulpointe area and meaning “red ravenala”.Description Plants solitary (never suckering), 6–10 meters tall (adult), trunk circumference (d.b.h.) 20–30 cm, juvenile laminae distributed like a fan, adult laminae arranged in an irregular to regular fan, 12–18 leaves simultaneously alive on the adult plant, 3 leaves between inflorescences. Leaves adult petiole 200–230 cm long, dark red, slightly to very waxy, sheath margin very developed (10 mm and more), red, entire, forming a three dimensional zigzag pattern (Fig. 3e), then splitting and drying on old leaves, petiole/lamina ratio 1.4–(1.7)–1.9, adult lamina (350 times 120) cm, lamina color dark green, juvenile lamina base non-decurrent. Inflorescences 1–2 live lateral inflorescences at a time, (60 times 70) cm (peduncle excluded), 10–12 bracts per inflorescence, bracts 260–360 (times) 50–80 mm, very waxy (Fig. 4e), margin color uniformly reddish-green, cincinnii of 8–12 flowers per bract, flowering sequentially, no colored stripe on bracteoles (apices sometimes suffused with pink). Flowers 220–250 mm long (ovary included), inferior ovary 40–60 mm long, perianth pure white to whitish, sepals narrowly triangular 180–230 (times) 12–16 mm, sheathing (fused) petals narrowly triangular 160–180 (times) 5 mm, free petal acicular 160–170 (times) 5 mm, free petal the same size as the remaining perianth with a mean free petal / mean fused petal length ratio = 1.0, petal blotches absent, stamens the same size (roughly) as the perianth, stamen 150–160 mm long, style 150–200 mm long, stigma 10 mm long, oblong with a basal constriction. Infructescences compact (bract bases imbricate at all stages of maturity), stiff and coriaceous persisting bracts on mature infructescences, old infructescences deciduous, 8–12 fruits per bract. Fruits 80–100 (times) 30–35 mm, trilocular septifragal capsule, apices truncate with a mucro (Fig. 2e), seeds shiny, dark brown, mostly globose, varying in shape according to their distribution in the capsule, ultramarine blue aril.Note This species is similar to R. hladikorum but is easily distinguished by, in addition to its petioles and its ecology, its truncate mucronate fruit apices, the shape of the synflorescence bracts and the absence of a red stripe on the cyme bracteoles.Identification key to the species of genus Ravenala More

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