Rorippa subumbellata
Encyclopedia
Rorippa subumbellata is a rare species of flowering plant in the mustard family
known by the common name Lake Tahoe yellowcress. It is known only from the shores of Lake Tahoe
, straddling the border between California
and Nevada
. There are an estimated fourteen populations of the plant still in existence. It grows only on the direct shoreline of the lake, occupying a seven-foot semi-aquatic zone between the high- and low-tide marks. It is directly impacted by recreational activities on the lake, enduring bombardment by boat wakes
, trampling, and construction of docks and other structures.
This perennial herb produces spreading, branching, hairy stems up to 20 centimeters long. The leaves are 1 to 3 centimeters long, oblong or lance-shaped, and wavy along the edges or divided into lobes. The inflorescence
is a compact raceme
of mustardlike flowers with yellow petals each about 3 millimeters long. The fruit is a hairless silique
a few millimeters wide containing tiny seeds.
The population sizes change with the lake's water level, with populations growing largest as water levels drop, exposing more sand habitat. High water levels may be beneficial at times, however, since they kill off competing plant species growing on the beaches. Restoration of this species has been hampered by low seed germination, but recent research has reduced this problem.
Brassicaceae
Brassicaceae, a medium sized and economically important family of flowering plants , are informally known as the mustards, mustard flowers, the crucifers or the cabbage family....
known by the common name Lake Tahoe yellowcress. It is known only from the shores of Lake Tahoe
Lake Tahoe
Lake Tahoe is a large freshwater lake in the Sierra Nevada of the United States. At a surface elevation of , it is located along the border between California and Nevada, west of Carson City. Lake Tahoe is the largest alpine lake in North America. Its depth is , making it the USA's second-deepest...
, straddling the border between California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
and Nevada
Nevada
Nevada is a state in the western, mountain west, and southwestern regions of the United States. With an area of and a population of about 2.7 million, it is the 7th-largest and 35th-most populous state. Over two-thirds of Nevada's people live in the Las Vegas metropolitan area, which contains its...
. There are an estimated fourteen populations of the plant still in existence. It grows only on the direct shoreline of the lake, occupying a seven-foot semi-aquatic zone between the high- and low-tide marks. It is directly impacted by recreational activities on the lake, enduring bombardment by boat wakes
Wake
A wake is the region of recirculating flow immediately behind a moving or stationary solid body, caused by the flow of surrounding fluid around the body.-Fluid dynamics:...
, trampling, and construction of docks and other structures.
This perennial herb produces spreading, branching, hairy stems up to 20 centimeters long. The leaves are 1 to 3 centimeters long, oblong or lance-shaped, and wavy along the edges or divided into lobes. The inflorescence
Inflorescence
An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Strictly, it is the part of the shoot of seed plants where flowers are formed and which is accordingly modified...
is a compact raceme
Raceme
A raceme is a type of inflorescence that is unbranched and indeterminate and bears pedicellate flowers — flowers having short floral stalks called pedicels — along the axis. In botany, axis means a shoot, in this case one bearing the flowers. In a raceme, the oldest flowers are borne...
of mustardlike flowers with yellow petals each about 3 millimeters long. The fruit is a hairless silique
Silique
A silique or siliqua is a fruit of 2 fused carpels with the length being more than three times the width. The outer walls of the ovary usually separate when ripe, leaving a persistent partition...
a few millimeters wide containing tiny seeds.
The population sizes change with the lake's water level, with populations growing largest as water levels drop, exposing more sand habitat. High water levels may be beneficial at times, however, since they kill off competing plant species growing on the beaches. Restoration of this species has been hampered by low seed germination, but recent research has reduced this problem.