Portal de Periódicos da CAPES

The Tamaricaceae in the southeastern United States

1989; Arnold Arboretum of Harvard University; Volume: 70; Linguagem: Inglês

10.5962/bhl.part.19790

2474-3283

W J Crins,

Plant Pathogens and Fungal Diseases

only on abaxial surface in Myricaria gennanica].Inflorescences spicate or racemiform, often aggregated in terminal panicles [or flowers solitary in Hololachna and Reaumwia].Flowers perfect [2 species of Tamarix dioecious], regular, small, hypogynous, 4-or 5-[6-]merous; pedicels subtended by small, scalelike bracts.Sepals 4 or 5 [6], free or slightly connate, persistent, imbricate.Petals 4 or 5 [6], alternating with and larger than sepals, free, sometimes persistent [with a pair of ligular appendages near base in Reaumuria], inserted at base of a fleshy or membranaceous disc, imbricate.Stamens 4 or 5 [to 10 in Tamarix, to 75 in Reaumuria], usually haplostemonous or obdiplostemonous, usually free [monadelphous in Myricaria, fasciculate in 5 bundles in Reaumuria]; filaments filiform; anthers tetrasporangiate, 2-locular, versatile, extrorse in Tamarix [introrse in Myricaria], longitudinally dehiscent, slightly longer than wide; pollen (2-) 3-(4-)colpate, simple or in tetrads, binucleate (in Tamarix) [trinucleate in Myricaria].Gynoecium or(2) 3 or 4 ( 5) carpels united in a compound, superior, unilocular ovary; placentation parietal, placentae sometimes intruded, making the ovary appear plurilocular near base and apex, or reduced, making placentation appear basal; styles 3[-5], distinct or connate at base; stigmas apical or decurrent adaxially [sessile in Myricaria]; ovules 2 to many on each placenta, with short funiculi, erect, anatropous, bitegmic, crassinucellar.Fruit a loculicidal, pyramidal capsule, the 3[-5] valves placcntifcrous at base, coriaceous; seeds long-pilose over entire surface [Reaumurieae] or at apex only, with unicellular hairs, which may be prolonged into a conspicuous hygroscopic coma (Tamariccae), micropyle formed by endostome; endosperm with development nuclear [cellular in Tamarix tctrandra], degenerating quickly in Tamariccae [persistent in Reaumurieae]; cotyledons 2, oblong, obtuse at apex, flat or plano-convex, the radicle short, conical, inferior; megagametophyte (embryo sac) tetrasporic, but postmeiotic development variable, usually Fritillaria or Adoxa type, embryogenesis of Solanad type, with broad, massive suspensor formed, polyembryony occasional.Base chromosome number 12. (Including ReaumuriaceaeEhrenberg.) Type genus: Tamarix A relatively small family of five genera {Hololachna Ehrenb., Myricaria Desv., Myrtama Ovcz.& Kinz., Reaumuria L., and TamarixL.)and about 100 species, occurring primarily in central Asia, the Middle East, northern Africa, and the Mediterranean region of Europe.Several species of Tamarix have been introduced into North America, and six of these have become naturalized in the Southeast.'The Tamaricaceae are one of numerous families that have been placed in the catchall order Parietales.Other early suggestions of relationship included the Guttiferales (Endlicher; Grisebach; Hallier, 1911), Rutiflorae (Caruel), and JOURNAL OF THE ARNOLD ARBORETUM [vol.70[six-]merous, while, pink, or even reddish flowers are quite small but are aggregated into panicles of racemes or spikes that provide spectacular displays.The capsules contain numerous small seeds that may be hairy over the entire surface (tribe Reaumurieae) or have long hairs at the chalazal end forming a conspicuous coma that aids in dispersal (tribe Tamariceae).Fossils of the Tamaricaceae are very few.Tamaricoxylon africanum (Krausel) Boureau, based on fossil wood, is identical in anatomy to modem Tamarix (Boureau).The fossils are from northern African Quaternary deposits and thus shed no light on the age of the family.An attribution of Oligocene age to one of these specimens is considered doubtful by Boureau.