Nature
Sheep sorrel (Rumex acetosella) is an invasive, perennial, wind-pollinated plant that can attain a height of about 15-40 cm. The leaves are typically 1-8 cm in length, varied shaped with a smooth texture. This plant is dioecious and possesses unisexual, reddish-yellow flowers. The seeds are achenes, around 1.5 mm (length), shiny red-brown and often found to be encased in a rough-textured, reddish-brown hull (1). The pollination period for Rumex species ranges from late spring to early summer. However, the pollination may intensify from late April until May and might continue till the summer period. A single sheep sorrel plant has been claimed to produce around 400 million pollen grains. This plant is an herb with an acrid taste attributed to the presence of oxalic acid. The seeds of this plant have been reported to be consumed by birds, whereas the leaves and the whole plant acts as a natural food source for deer and rabbits (2).
Habitat
Sheep sorrel is reported to be prevalent along roadsides, open pastures, grasslands, floodplains, and under forest canopies. This plant is predominantly found in temperate coastal regions. It can sustain severe climatic conditions like extreme cold winters and hot, dry summers and is known to be drought-tolerant (1). Sheep sorrel can grow in varying altitudes ranging from 4500 to 8700 feet (2). This plant can thrive in various soil conditions like silty loam, sandy loam, gravel, heavy clay, etc. It can even survive in acidic (like low pH of 4.7) soil with low fertility (1).
Taxonomy
Around 200 weed species belonging to the genus Rumex are claimed to be found in the temperate climate regions in the Northern Hemisphere. Twenty-four of these species have been reported to be prevalent in California, while 20 species in the North-eastern region (2).
| Taxonomic tree of Sheep sorrel (3) |
|---|
| Domain |
Eukaryota |
| Kingdom |
Plantae |
| Phylum |
Spermatophyta |
| Subphylum |
Angiospermae |
| Class |
Dicotyledonae |
| Order |
Polygonales |
| Family |
Polygonaceae |
| Genus |
Rumex |
| Species |
Rumex acetosella |
| Taxonomic tree of Sheep sorrel (3) |
|---|
Tissue
Pollens of species from the genus Rumex are spheroidal (22 - 30 µm in diameter) and either tetracolporate (consisting of 4 colpi) or stephanocolporate (consisting of >3 colpi). The walls of these pollen grains are tectate (sculptured), with tightly arranged columellae, of around 1.5 µm thickness. These pollen grains have a reticulate (net-like) surface containing grooves of varied sizes. Each of these grooves encases a tiny, ellipsoidal pore in the center (2).
To date (24-January-2021), no allergenic proteins from sheep sorrel pollen have been identified in the IUIS database (4).
