Marlimorimia L.P. Queiroz, L.M. Borges, Marc.F. Simon & P.G. Ribeiro, 2022

Borges, Leonardo M., Inglis, Peter W., Simon, Marcelo F., Ribeiro, Petala Gomes & de Queiroz, Luciano P., 2022, Misleading fruits: The non-monophyly of Pseudopiptadenia and Pityrocarpa supports generic re-circumscriptions and a new genus within mimosoid legumes, PhytoKeys 205, pp. 239-259 : 239

2. Marlimorimia L.P. Queiroz, L.M. Borges, Marc.F. Simon & P.G. Ribeiro gen. nov.

Newtonia sect. Neonewtonia Burkart, Fl. Il. Catarin. fasc. LEGU: 285. 1979, syn. nov. Type. Newtonia nitida (Benth.) Brenan (= Marlimorimia contorta (DC.) L.P. Queiroz & P.G. Ribeiro).

Diagnosis.

Marlimorimia shares with Pityrocarpa the follicle, a fruit dehiscing along the lower suture only, and flat, compressed winged seeds, which lack a pleurogram. It can be differentiated from Pityrocarpa by the position of the extrafloral nectary on the petiole (from the base to the mid-petiole in Marlimorimia vs. between or just below the first pair of pinnae in Pityrocarpa ); inflorescence spikes clustered in terminal pseudoracemes or in fascicles at efoliate nodes, surpassed by mature leaves (vs. solitary spikes in the axils of coeval leaves); petals united and joined into a gamopetalous corolla (vs. petals free and glabrous); and fruits with margins straight to shallowly sinuous (vs. margins deeply constricted).

Type.

Marlimorimia contorta (DC.) L.P. Queiroz & P.G. Ribeiro

Description.

Unarmed trees. Leaves bipinnate; petiole with an extrafloral nectary well below the first pair of pinnae, close to the pulvinus, always below mid-petiole; pinnae 5-10 to many pairs per leaf (2-3 pairs in M. colombiana and 3-5 in M. bahiana ); leaflets mostly> 10 pairs per pinna, (6-8 in M. colombiana ), mostly oblong to linear from an asymmetrical base, rarely rhomboid ( M. bahiana ). Inflorescences spikes, grouped in fascicles, these being arranged in terminal pseudoracemes or forming clusters below the coeval leaves. Flowers pentamerous; petals united into a gamopetalous corolla, pubescent; stamens 10, anther gland present; ovary shortly stipitate and included or exserted from the corolla. Fruit a follicle, dehiscing along the lower suture, flat compressed, straight, curved or longitudinally twisted, the margins usually straight, rarely irregularly sinuous and only becoming constricted where the seeds fail to develop ( M. bahiana and M. warmingii ), valves coriaceous, thin or thick. Seeds flat compressed with a coriaceous testa, presenting a narrow or somewhat wider marginal wing, pleurogram lacking; embryo with a developed, multifid plumule (unknown in M. colombiana and M. pittieri ). Seedlings with pinnate or bipinnate eophylls (unknown in M. bahiana , M. colombiana and M. pittieri ).

Distribution.

Marlimorimia comprises six species with a bicentric distribution in the two main areas of tropical humid forests in South America. Three species occur in eastern Brazil, two of which are restricted to the Atlantic wet forests ( Marlimorima bahiana and M. warmingii ) and M. contorta , which extends to inland semi-deciduous forests. The three other species are distributed in northern South America. Marlimorimia psilostachya is widely distributed across Amazonia, sparsely extending to Central America (Costa Rica) and M. colombiana and M. pittieri have restricted ranges in Colombia and Venezuela, respectively.

Etymology.

The genus Marlimorimia is named in honour of Dr. Marli Pires Morim, taxonomist at the Rio de Janeiro Botanical Garden, for her outstanding contribution to our knowledge of the diversity and taxonomy of Brazilian mimosoid legumes.

Notes.

The new genus Marlimorimia is proposed to accommodate a monophyletic group of species, previously classified in Pseudopiptadenia (sensu Lewis and Lima 1991; Luckow 2005), but which could not retain the genus name, because its type species is now included in Pityrocarpa .

Besides the molecular phylogenetic evidence, morphology also supports recognition of Marlimorimia as distinct from Pityrocarpa . Marlimorimia brings together most of the species formerly placed in Pseudopiptadenia which have multipinnate leaves, small oblong to linear leaflets and fruits with straight (or shallowly sinuous) margins. Marlimorimia bahiana and M. colombiana , however, have leaves with few pinnae and rhomboid leaflets.

Species of Marlimorimia have more complex inflorescences than those of Pityrocarpa . While the spikes of Pityrocarpa are solitary in the axils of coevally developing leaves, Marlimorimia species have spikes in fascicles of 2-3, which are arranged in terminal efoliate pseudoracemes or clustered on nodes below mature leaves (Fig. 3 ). Sometimes, as leaves expand, Marlimorimia synflorescences may resemble those of Pityrocarpa and Parapiptadenia (e.g. particular specimens of M. contorta such as Hatschbach 50149 [NY]). Nonetheless, flowers of Marlimorimia have pubescent petals united into a gamopetalous corolla (vs. free glabrous petals in the majority of Pityrocarpa species).

Two types of fruits are found in Marlimorimia (Fig. 5 ). Some species have long linear fruits, frequently curved or longitudinally twisted with straight margins ( M. colombiana , M. contorta , M. pittieri and M. psilostachya ), while M. bahiana and M. warmingii have oblong fruits with shallowly sinuous margins. The valves of the fruits are woody, although usually thin, becoming thicker and harder in M. warmingii .

The seeds of Marlimorimia , although superficially similar to those of most species of Pityrocarpa , have embryos with multifid plumules that result in seedlings with pinnate or bipinnate eophylls ( Lima 1985; Lewis and Lima 1991).

Figures

Figure 3. Inflorescences of Parapiptadenia, Pityrocarpa and Marlimorimia A Parapiptadenia pterosperma (Benth.) Brenan showing reddish inflorescences in the axils of coeval leaves B Pa. rigida (Benth.) Brenan showing yellowish inflorescences and fruits with valves plicate above the seeds C Pityrocarpa brenanii showing whitish, solitary spikes in the axils of coeval leaves D Pi. moniliformis showing yellowish, solitary spikes in the axil of a coeval leaf E Marlimorimia bahiana (G. P. Lewis & M. P. Lima) L. P. Queiroz & L. M. Borges, showing whitish spikes clustered in efoliate terminal pseudoracemes F Marlimorimia sp. showing yellowish spikes clustered in efoliate terminal pseudoracemes (Photos: A PG Ribeiro; B RT de Queiroz C-E LP Queiroz; F G Siqueira).

Figure 5. Fruits of Marlimorimia species A Marlimorimia bahiana (from Amorim 1009, NY) B Marlimorimia colombiana (from Killip 16268, NY) C Marlimorimia contorta (from Gomes 257, NY) D Marlimorimia pittieri (from Guevara 1264, F) E Marlimorimia psilostachya (from Rabelo 2753, NY) F Marlimorimia warmingii (from Nunes et al. 2, NY).