DOI: 10.5061/dryad.bc7tv17
title: Data from: Seed morphology of Ruellieae Species (Acanthaceae) in Brazil and its taxonomic implications

description: Ruellieae is a highly diverse tribe of Acanthaceae in Brazil, and
 morphological studies of its seeds have revealed important information
 about the systematics of the tribe. We analyzed the seed morphology of
 Brazilian species of Ruellieae, using stereoscopic, light, and scanning
 electron microscopy. The best-sampled genus was Ruellia (53 species),
 followed by Dyschoriste (seven), and Hygrophila (three); including
 external groups, a total of 65 species of Ruellieae (68 of Acanthaceae)
 were sampled. We observed capsular fruits with explosive dehiscence,
 important for autochory, and discoid seeds covered by hygroscopic and
 mucilaginous trichomes. The characters most relevant to the taxonomy of
 the groups were fruit shape, number of ovules, and the distribution,
 shape, and number of rings on the seed trichomes, the latter two addressed
 here for the first time. Those characters proved useful for discriminating
 and characterizing the sampled genera within Ruellieae, and especially the
 infrageneric clades of Ruellia. Based on the morphological patterns
 observed, we provide a key for those taxa, and suggest the infrageneric
 placement of unclassified Ruellia species: R. hypericoides and Ruellia sp.
 4 for the clade “Ebracteolati” s. l., Ruellia spp. 2 and 3 for “R.
 inflata”, Ruellia sp. 1 for “Euruellia” s. s., and R. anamariae for the
 clade “Blechum”. In a broader context, we corroborate the finding that
 partial loss of seed trichomes is exclusive to one of the two large
 lineages of Neotropical Ruellia (lineage II). The hygroscopic and
 mucilaginous trichomes of Ruellieae seeds play important roles in water
 retention, germination, protection, and secondary dispersal, and we
 discuss some aspects of secondary hydrochory and epizoochory on medium-
 and long-range dispersal of Ruellieae, including transatlantic distances.
description: Supplemental Figure
 1Fruits and seeds of
 Dyschoriste species. A–E. D. humilis (STM on A, SEM on B–E): A–B. Seed. C.
 Seed apex. D. Seed base. E. Seed trichomes with secondary annular
 thickenings. F–K. D. hygrophiloides (STM on F–G, SEM on H–K): F. Fruit.
 G–H. Seed. I. Seed apex. J. Seed base. K. Seed trichomes with secondary
 annular thickenings. L–R. D. lavandulacea (STM on L–M, SEM on N–R): L.
 Fruit. M–N. Seed. O. Seed apex. P. Seed base. Q. Seed trichomes with
 secondary annular thickenings. R. Hilar cells, some partially
 differentiated into trichomes. S–T. D. maranhonis (STM): S. Fruit. T.
 Seed. [STM=stereomicroscopy; SEM=scanning electron
 microscopy].SFig.1.tifSupplemental Figure 2Fruits and seeds of Dyschoriste species. A–D. D. maranhonis (SEM): A. Seed. B. Seed apex. C. Seed base. D. Seed trichomes with secondary annular thickenings. E–J. D. serpyllum (STM on E–F, SEM on G–J): E. Fruit. F–G. Seed. H. Seed apex. I. Seed base. J. Seed trichomes with secondary annular thickenings. K–Q. D. trichanthera (STM on K–L, SEM on M–Q): K. Fruit. L–M. Seed. N. Seed apex. O. Seed base. P. Seed trichomes with secondary annular thickenings. Q. Hilar cells, some partially differentiated into trichomes. R–T. Dyschoriste sp. (STM on R–S, SEM on T): R. Fruit. S–T. Seed. [STM=stereomicroscopy; SEM=scanning electron microscopy].SFig.2.tifSupplemental Figure 3Fruits and seeds of Dyschoriste (A–D) and Hygrophila (E–T) species. A–D. Dyschoriste sp. (SEM): A. Seed apex. B. Seed base. C. Seed trichomes with secondary annular thickenings. D. Hilar cells, some partially differentiated into trichomes. E–J. H. costata (STM on E–F, SEM on G–J): E. Fruit. F–G. Seed. H. Seed apex. I. Seed base. J. Seed trichomes with secondary annular thickenings. K–Q. H. guianensis (STM on K–L, SEM on M–Q): K. Fruit. L–M. Seed. N. Seed apex. O. Seed base. P. Seed trichomes with secondary annular thickenings. Q. Hilar cells, some partially differentiated into trichomes. R–T. H. oblongifolia (STM on R–S, SEM on T): R. Fruit. S–T. Seed. [STM=stereomicroscopy; SEM=scanning electron microscopy].SFig.3.tifSupplemental Figure 4Fruits and seeds of Hygrophila (A–C) and Ruellia species from the clade “Ebracteolati” (D–T). A–C. H. oblongifolia (SEM): A. Seed apex. B. Seed base. C. Seed trichomes with secondary annular thickenings. D–J. R. adenocalyx (STM on D–E, SEM on F–J): D. Fruit. E–F. Seed. G. Seed apex. H. Seed base. I–J. Seed trichomes with secondary annular thickenings. K–Q. R. angustior (STM on K–L, SEM on M–Q): K. Fruit. L–M. Seed. N. Seed apex. O. Seed base. P–Q. Seed trichomes with secondary annular thickenings. R–T. R. bahiensis (STM on R–S, SEM on T): R. Fruit. S–T. Seed. [STM=stereomicroscopy; SEM=scanning electron microscopy].SFig.4.tifSupplemental Figure 5Fruits and seeds of Ruellia species from the clade “Ebracteolati”. A–C. R. bahiensis (SEM): A. Seed apex. B. Seed base. C. Seed trichomes with secondary annular thickenings. D–I. R. beyrichiana (STM on D–E, SEM on F–I): D. Fruit. E–F. Seed. G. Seed apex. H. Seed base. I. Seed trichomes with secondary annular thickenings. J–O. R. bulbifera. (STM on J–K, SEM on L–O): J. Fruit. K–L. Seed. M. Seed apex. N. Seed base. O. Seed trichomes with secondary annular thickenings. P–T. R. densa (STM on P–Q, SEM on R–T): P. Fruit. Q–R. Seed. S. Seed apex. T. Seed base. [STM=stereomicroscopy; SEM=scanning electron microscopy].SFig.5.tifSupplemental Figure 6Fruits and seeds of Ruellia species from the clade “Ebracteolati”. A. R. densa (SEM): Seed trichomes with secondary annular thickenings. B–G. R. erythropus (STM on B–C, SEM on D–G): B. Fruit. C–D. Seed. E. Seed apex. F. Seed base. G. Seed trichomes with secondary annular thickenings. H–M. R. foetida (STM on H–I, SEM on J–M): H. Fruit. I–J. Seed. K. Seed apex. L. Seed base. M. Seed trichomes with secondary annular thickenings. N–T. R. geminiflora (STM on N–O, SEM on P–T): N. Fruit. O–P. Seed. Q. Seed apex. R. Seed base. S–T. Seed trichomes with secondary annular thickenings. [STM=stereomicroscopy; SEM=scanning electron microscopy].SFig.6.tifSupplemental Figure 7Fruits and seeds of Ruellia species from the clade “Ebracteolati”. A–G. R. hypericoides (STM on A–B, SEM on C–G): A. Fruit. B–C. Seed. D. Seed apex. E. Seed base. F–G. Seed trichomes with secondary annular thickenings. H–M. R. incomta (STM on H–I, SEM on J–M): H. Fruit. I–J. Seed. K. Seed apex. L. Seed base. M. Seed trichomes with secondary annular thickenings. N–T. R. multifolia (STM on N–O, SEM on P–T): N. Fruit. O–P. Seed. Q. Seed apex. R. Seed base. S–T. Seed trichomes with secondary annular thickenings. [STM=stereomicroscopy; SEM=scanning electron microscopy].SFig.7.tifSupplemental Figure 8Fruits and seeds of Ruellia species from the clade “Ebracteolati”. A–F. R. nitens (STM on A–B, SEM on C–F): A. Fruit. B–C. Seed. D. Seed apex. E. Seed base. F. Seed trichomes with secondary annular thickenings. G–L. R. tubiflora (STM on G–H, SEM on I–L): G. Fruit. H–I. Seed. J. Seed apex. K. Seed base. L. Seed trichomes with secondary annular thickenings. M–R. R. verbasciformis (STM on M–N, SEM on O–R): M. Fruit. N–O. Seed. P. Seed apex. Q. Seed base. R. Seed trichomes with secondary annular thickenings. S–T. R. yurimaguensis (STM): S. Fruit. T. Seed. [STM=stereomicroscopy; SEM=scanning electron microscopy].SFig.8.tifSupplemental Figure 9Fruits and seeds of Ruellia species from the clades “Ebracteolati” (A–K) and “R. inflata” (L–T). A–E. R. yurimaguensis (SEM): A. Seed. B. Seed apex. C. Seed base. D. Seed trichomes with secondary annular thickenings. E. Hilar cells, some partially differentiated into trichomes. F–K. Ruellia sp. 4 (STM on F–G, SEM on H–K): F. Fruit. G–H. Seed. I. Seed apex. J. Seed base. K. Seed trichomes with secondary annular thickenings. L–Q. R. brevicaulis (STM on L–M, SEM on N–Q): L. Fruit. M–N. Seed. O. Seed apex. P. Seed base. Q. Seed trichomes with secondary annular thickenings. R–T. R. elegans (STM on R–S, SEM on T): R. Fruit. S–T. Seed. [STM=stereomicroscopy; SEM=scanning electron microscopy].SFig.9.tifSupplemental Figure 10Fruits and seeds of Ruellia species from the clade “R. inflata”. A–D. R. elegans (SEM): A. Seed apex. B. Seed base. C. Seed trichomes with secondary annular thickenings. D. Hilar cells, some partially differentiated into trichomes. E–J. R. exserta (STM on E–F, SEM on G–J): E. Fruit. F–G. Seed. H. Seed apex. I. Seed base. J. Seed trichomes with secondary thickenings. K–Q. R. inflata (STM on K–L, SEM on M–Q): K. Fruit. L–M. Seed. N. Seed apex. O. Seed base. P. Seed trichomes with secondary annular thickenings. Q. Hilar cells, some partially differentiated into trichomes. R–T. R. subsessilis (STM on R–S, SEM on T): R. Fruit. S–T. Seed. [STM=stereomicroscopy; SEM=scanning electron microscopy].SFig.10.tifSupplemental Figure 11Fruits and seeds of Ruellia species from the clades “R. inflata” (A–Q) and “R. humilis” (R–T). A–C. R. subsessilis (SEM): A. Seed apex. B. Seed base. C. Seed trichomes with secondary annular thickenings. D–J. Ruellia sp. 2 (STM on D–E, SEM on F–J): D. Fruit. E–F. Seed. G. Seed apex. H. Seed base. I. Seed trichomes with secondary thickenings. J. Hilar cells, some partially differentiated into trichomes. K–Q. Ruellia sp. 3 (STM on K–L, SEM on M–Q): K. Fruit. L–M. Seed. N. Seed apex. O. Seed base. P. Seed trichomes with secondary annular thickenings. Q. Hilar cells, some partially differentiated into trichomes. R–T. R. humilis (STM on R–S, SEM on T): R. Fruit. S–T. Seed. [STM=stereomicroscopy; SEM=scanning electron microscopy].SFig.11.tifSupplemental Figure 12Fruits and seeds of Ruellia species from the clades “R. humilis” (A–C) and “Euruellia” s. s. (D–T). A–C. R. humilis (SEM): A. Seed apex. B. Seed base. C. Seed trichomes with secondary annular thickenings. D–I. R. hygrophila. (STM on D–E, SEM on F–I): D. Fruit. E–F. Seed. G. Seed apex. H. Seed base. I. Seed trichomes with secondary annular thickenings. J–O. R. macrosolen (STM on J–K, SEM on L–O): J. Fruit. K–L. Seed. M. Seed apex. N. Seed base. O. Seed trichomes with secondary annular thickenings. P–T. R. morongii (STM on P–Q, SEM on R–T): P. Fruit. Q–R. Seed. S. Seed apex. T. Seed base. [STM=stereomicroscopy; SEM=scanning electron microscopy].SFig.12.tifSupplemental Figure 13Fruits and seeds of Ruellia species from the clades “Euruellia” s. s. (A–R) and “R. devosiana” (S–T). A. R. morongii (SEM): A. Seed trichomes with secondary annular thickenings. B–F. R. nudiflora (STM on B–C, SEM on D–F): B. Fruit. C–D. Seed. E. Seed base. F. Seed trichomes with secondary annular thickenings. G–M. R. tuberosa (STM on G–H, SEM on I–M): G. Fruit. H–I. Seed. J. Seed apex. K. Seed base. L. Seed trichomes with secondary annular thickenings. M. Hilar cells, some partially differentiated into trichomes. N–R. Ruellia sp. 1 (STM on N–O, SEM on P–R): N. Fruit. O–P. Seed. Q. Seed base. R. Seed trichomes with secondary annular thickenings. S–T. R. affinis (STM): S. Fruit. T. Seed. [STM=stereomicroscopy; SEM=scanning electron microscopy].SFig.13.tifSupplemental Figure 14Fruits and seeds of Ruellia species from the clades “R. devosiana” (A–K) and “R. inundata” (L–T). A–D. R. affinis (SEM): A. Seed. B. Seed apex. C. Seed base. D. Seed trichomes with secondary annular thickenings and hilar cells. E–K. R. makoyana (STM on E–F, SEM on G–K): E. Fruit. F–G. Seed. H. Seed apex. I. Seed base. J. Seed trichomes with secondary annular thickenings. K. Mid-surface of the seed coat, lacking trichomes. L–R. R. asperula (STM on L–M, SEM on N–R): L. Fruit. M–N. Seed. O. Seed apex. P. Seed base. Q. Seed trichomes with secondary annular thickenings. R. Mid-surface of the seed coat, lacking trichomes. S–T. R. cearensis (STM): S. Fruit. T. Seed. [STM=stereomicroscopy; SEM=scanning electron microscopy].SFig.14.tifSupplemental Figure 15Fruits and seeds of Ruellia species from the clade “R. inundata”. A–E. R. cearensis (SEM): A. Seed. B. Seed apex. C. Seed base. D. Seed trichomes with secondary annular thickenings. E. Mid-surface of the seed coat, lacking trichomes. F–L. R. ochroleuca (STM on F–G, SEM on H–L): F. Fruit. G–H. Seed. I. Seed apex. J. Seed base. K. Seed trichomes with secondary annular thickenings. L. Mid-surface of the seed coat, lacking trichomes. M–S. R. paniculata (STM on M–N, SEM on O–S): M. Fruit. N–O. Seed. P. Seed apex. Q. Seed base. R. Seed trichomes with secondary annular thickenings. S. Mid-surface of the seed coat, lacking trichomes. T. R. viscidula (STM): Fruit. [STM=stereomicroscopy; SEM=scanning electron microscopy].SFig.15.tifSupplemental Figure 16Fruits and seeds of Ruellia species from the clades “R. inundata” (A–F) and “Physiruellia” (G–T). A–F. R. viscidula (STM on A, SEM on B–F): A–B. Seed. C Seed apex. D. Seed base. E. Seed trichomes with secondary annular thickenings. F. Mid-surface of the seed coat, lacking trichomes. G–M. R. amplexicaulis (STM on G–H, SEM on I–M): G. Fruit. H–I. Seed. J. Seed apex. K. Seed base. L. Seed trichomes with secondary annular thickenings. M. Mid-surface of the seed coat, lacking trichomes. N–T. R. angustiflora (STM on N–O, SEM on P–T): N. Fruit. O–P. Seed. Q. Seed apex. R. Seed base. S. Seed trichomes with secondary annular thickenings. T. Mid-surface of the seed coat, lacking trichomes. [STM=stereomicroscopy; SEM=scanning electron microscopy].SFig.16.tifSupplemental Figure 17Fruits and seeds of Ruellia species from the clade “Physiruellia”. A–F. R. costata (STM on A–B, SEM on C–F): A. Fruit. B–C. Seed. D. Seed apex. E. Seed trichomes with secondary annular thickenings. F. Mid-surface of the seed coat, lacking trichomes. G–M. R. epallocaulos. (STM on G–H, SEM on I–M): G. Fruit. H–I. Seed. J. Seed apex. K. Seed base. L. Seed trichomes with secondary annular thickenings. M. Mid-surface of the seed coat, lacking trichomes. N–T. R. haenkeana (STM on N–O, SEM on P–T): N. Fruit. O–P. Seed. Q. Seed apex. R. Seed base. S. Seed trichomes with secondary annular thickenings. T. Mid-surface of the seed coat, lacking trichomes. [STM=stereomicroscopy; SEM=scanning electron microscopy].SFig.17.tifSupplemental Figure 18Fruits and seeds of Ruellia from the clade “Physiruellia”. A–F. R. jussieuoides (STM on A–B, SEM on C–F): A. Fruit. B–C. Seed. D. Seed apex. E. Seed trichomes with secondary annular thickenings. F. Mid-surface of the seed coat, lacking trichomes. G–M. R. menthoides (STM on G–H, SEM on I–M): G. Fruit. H–I. Seed. J. Seed apex. K. Seed base. L. Seed trichomes with secondary annular thickenings. M. Mid-surface of the seed coat, lacking trichomes. N–T. R. nitida (STM on N–O, SEM on P–T): N. Fruit. O–P. Seed. Q. Seed apex. R. Seed base. S. Seed trichomes with secondary annular thickenings. T. Mid-surface of the seed coat, lacking trichomes. [STM=stereomicroscopy; SEM=scanning electron microscopy].SFig.18.tifSupplemental Figure 19Fruits and seeds of Ruellia from the clade “Physiruellia”. A–G. R. proxima (STM on A–B, SEM on C–G): A. Fruit. B–C. Seed. D. Seed apex. E. Seed base. F. Seed trichomes with secondary annular thickenings. G. Mid-surface of the seed coat, lacking trichomes. H–N. R. rubra (STM on H–I, SEM on J–N): H. Fruit. I–J. Seed. K. Seed apex. L. Seed base. M. Seed trichomes with secondary annular thickenings. N. Mid-surface of the seed coat, lacking trichomes. O–T. R. terminalis (STM on O–P, SEM on Q–T): O. Fruit. P–Q. Seed. R. Seed apex. S. Seed base. T. Seed trichomes with secondary annular thickenings. [STM=stereomicroscopy; SEM=scanning electron microscopy].SFig.19.tifSupplemental Figure 20Fruits and seeds of Ruellia species from the clades “Physiruellia” (A) and “Blechum” (B–T). A. R. terminalis (SEM): Mid-surface of the seed coat, lacking trichomes. B–I. R. anamariae (STM on B–C, SEM on D–H): B. Fruit. C–D. Seed. E. Seed apex. F. Seed base. G. Seed trichomes with secondary annular thickenings. H. Mid-surface of the seed coat, lacking trichomes. I–O. R. blechum (STM on I–J, SEM on K–O): I. Fruit. J–K. Seed. L. Seed apex. M. Seed base. N. Seed trichomes lageniform, lacking secondary annular thickenings. O. Wart on the mid-surface of the seed coat. P–T. R. macrantha (STM on P–Q, SEM on R–T): P. Fruit. Q–R. Seed. S. Seed apex. T. Seed base. [STM=stereomicroscopy; SEM=scanning electron microscopy].SFig.20.tifSupplemental Figure 21Fruits and seeds of Ruellia species from the clade “Blechum” (A–I) and of species from the external groups Brillantaisia (J–O) and Strobilanthes (P–T). A–B. R. macrantha (SEM): A. Seed trichomes with secondary annular thickenings. B. Mid-surface of the seed coat, lacking trichomes. C–I. Ruellia neesiana (STM on C–D, SEM on E–I): C. Fruit. D–E. Seed. F. Seed apex. G. Seed base. H. Seed trichomes with secondary annular thickenings. I. Mid-surface of the seed coat, lacking trichomes. J–O. B. lamium (STM on J–K, SEM on L–O): J. Fruit. K–L. Seed. M. Seed apex. N. Seed base. O. Seed trichomes with secondary annular thickenings. P–T. S. dyeriana (STM on P–Q, SEM on R–T): P. Fruit. Q–R. Seed. S. Seed apex. T. Seed base. [STM=stereomicroscopy; SEM=scanning electron microscopy].SFig.21.tifSupplemental Figure 22Fruits and seeds of species from the external groups Strobilanthes (A–B), Barleria (C–I), Lepidagathis (J–O) and Odontonema (P–T). A–B. S. dyeriana (SEM): Seed trichomes with secondary annular thickenings. C–I. B. cristata (STM on C–D, SEM on E–I): C. Fruit. D–E. Seed. F. Seed apex. G. Seed base. H–I. Seed trichomes, lacking secondary thickenings. J–O. L. sessilifolia (STM on J–K, SEM on L–O): J. Fruit. K–L. Seed. M. Seed apex. N. Seed base. O. Seed trichomes, lacking secondary thickenings. P–T. O. barlerioides (STM on P–Q, SEM on R–T): P. Fruit. Q–R. Seed. S–T. Glabrous and rugulate seed coat surface. [STM=stereomicroscopy; SEM=scanning electron microscopy].SFig.22.tifTable 1Fruit and seed morphological characters of the species studied. The species of Ruellia with the symbol “(N)” are those for which infrageneric placements are suggested here, based on the morphological patterns observed.Table1.pdfTable 2Morphology of the seed trichomes of the species studied. The species of Ruellia with the symbol “(N)” are those whose infrageneric placement is suggested here, based on the morphological patterns observed.Table2.pdfTable 3Morphological characters of the cells of the mid-region of the seed coat of the species studied that show at least part of the seed coat not covered by trichomes. The terminology follows Barthlott (1981).Table3.pdfTable4Diameter measurements of the species studied (n = 10), where x ̅ ±s_x ̅ = average ± average standard deviation; C.I. = confidence interval. The following symbols indicate: “*” n &lt; 10; “**” n &lt; 5; “***” n = 1.