Monographs Details: Juncus tenuis Willd. var. tenuis
Authority: Balslev, Henrik. 1996. Juncaceae. Fl. Neotrop. Monogr. 68: 1-167. (Published by NYBG Press)
Synonyms:Juncus macer Gray
Description:Variety Description - Perennial, cespitose herbs to 60 cm tall. Rhizome densely branching. Culms smooth or sometimes slightly longitudinally ridged. Auricles 0.5-1.5 mm long, usually longer than wide, rounded, thin, scariose. Leaf blades flat, adaxial side with a band of hyaline cells occupying ¾ or more of the width, only the margins with dense, chlorophyll-filled cells. Inflorescence composed of several few-flowered, unilateral cymes, branching irregular and inflorescence not equally dense throughout, and relatively long, flower-free branch segments alternate with more clustered sections. Lower inflorescence bract similar to basal leaves, distal ones gradually shorter. Tepals recurving apically toward maturity. Capsule shorter than the tepals when mature, thin walled, the valves not recurved along the seams and the capsule therefore not 3-keeled.


Distribution and Ecology: This is the common variety of J. tenuis found throughout temperate North America, and it is the one introduced to Japan, New Zealand, and Europe, where it has been given many different names of which J. macer is the one most commonly used. In the neotropical region it occurs throughout the Mexican and Central American highlands, on Jamaica and Puerto Rico, and in the Andes from Venezuela to Ecuador and in Argentina. It is weedy and commonly found at elevations of 1000-3000 m, along roads and in places where the soil is disturbed and wet from seeping water. In Ecuador, where I have been able to observe it in the field, it is found only in high-rainfall areas, which indicates that the seeds will not survive prolonged periods of drought. Dispersal is facilitated by the ability of the outer seed coat to swell into a sticky, gelatinous cover that adheres to passersby, humans and others.

Distribution:Mexico North America| Chiapas Mexico North America| Coahuila Mexico North America| Guerrero Mexico North America| Hidalgo Mexico North America| México Mexico North America| Oaxaca Mexico North America| Veracruz Mexico North America| Guatemala Central America| Baja Verapaz Guatemala Central America| Chimaltenango Guatemala Central America| Quiché Guatemala Central America| Guatemala Central America| Huehuetenango Guatemala Central America| Jalapa Guatemala Central America| Quezaltenango Guatemala Central America| Zacapa Guatemala Central America| San Marcos Guatemala Central America| Sololá Guatemala Central America| Totonicapán Guatemala Central America| Honduras Central America| El Paraíso Honduras Central America| Copán Honduras Central America| Cortés Honduras Central America| Intibucá Honduras Central America| La Paz Honduras Central America| Morazán Honduras Central America| Ocotepeque Honduras Central America| Olancho Honduras Central America| El Salvador Central America| Chalatenango El Salvador Central America| Costa Rica South America| Cartago Costa Rica Central America| Heredia Costa Rica Central America| San José Costa Rica Central America| Jamaica South America| Puerto Rico South America| Colombia South America| Antioquia Colombia South America| Boyacá Colombia South America| Caldas Colombia South America| Cauca Colombia South America| Chocó Colombia South America| Cundinamarca Colombia South America| Norte de Santander Colombia South America| Putumayo Colombia South America| Quindío Colombia South America| Santander Colombia South America| Tolima Colombia South America| Valle del Cauca Colombia South America| Venezuela South America| Táchira Venezuela South America| Ecuador South America| Azuay Ecuador South America| Loja Ecuador South America| Napo Ecuador South America| Pichincha Ecuador South America| Tungurahua Ecuador South America| Zamora-Chinchipe Ecuador South America|