FIRST HOST RECORD FOR THE ROOT PARASITE Corynaea crassa (BALANOPHORACEAE) / Primer registro de la hemiparásita de raíz Corynaea crassa (Balanophoraceae)

Corynaea crassa is a root hemiparasitc plant infrequent in nature. There is little information regarding their natural history, in particular their host range. In this study we dig 32 tubers and followed their parasitized roots to determine the species host. We found Bocconia frutescens (Papaveraceae), Verbesina sp. (Asteraceae), Cayaponia sp. (Cucurbitaceae) y Palicourea sp.(Rubiaceae) as natural hosts of C. crassa. This is the first host record available for C. crassa and provides some bases for its conservation in natural habitats.

Corynaea crassa es una planta hemiparásita de raíz poco común y de la cual sabemos muy poco acerca de su historia natural y en particular sobre su rango de hospederos. En este estudio excavamos 32 tubérculos de dicha especie y seguimos las raíces que estaban parasitando para determinar su identidad. Encontramos Bocconia frutescens (Papaveraceae), Verbesina sp. (Asteraceae), Cayaponia sp. (Cucurbitaceae) y Palicourea sp. (Rubiaceae). Este es el primer registro de hospederos disponible para la especies y este tipo de información es de gran utilidad para las conservación de C. crassa en hábitats naturales.

Diversity and host specificity of endophytic Rhizoctonia-like fungi from tropical orchids.

All orchids have an obligate relationship with mycorrhizal symbionts. Most orchid mycorrhizal fungi are classified in the form-genus Rhizoctonia. This group includes anamorphs of Tulasnella, Ceratobasidium, and Thanatephorus. Rhizoctonia can be classified according to the number of nuclei in young cells (multi-, bi-, and uninucleate). From nine Puerto Rican orchids we isolated 108 Rhizoctonia-like fungi. Our isolates were either bi- or uninucleate, the first report of uninucleate Rhizoctonia-like fungi as orchid endophytes. We sequenced the internal transcribed spacer (ITS) region of nuclear ribosomal DNA from 26 isolates and identified four fungal lineages, all related to Ceratobasidium spp. from temperate regions. Most orchid species hosted more than one lineage, demonstrating considerable variation in mycorrhizal associations even among related orchid species. The uninucleate condition was not a good phylogenetic character in mycorrhizal fungi from Puerto Rico. All four lineages were represented by fungi from Tolumnia variegata, but only one lineage included fungi from Ionopsis utricularioides. Tropical epiphytic orchids appear to vary in degree of specificity in their mycorrhizal interactions more than previously thought.