|
| |||||
|
|
|
GRASSES
OF THE COLUMBIA BASIN OF BRITISH COLUMBIA All three groups of the grasslike plants (grasses, sedges, rushes) are monocotyledons -- plants that have one seed leaf. All three groups produce mostly narrow leaves with parallel veins. The flowers are relatively obscure and difficult to work with at first glance. To decide whether a plant is a grass, sedge or rush, begin by looking at the stem. Observe first whether the stem is hollow or solid. Generally if the stem is hollow you have a grass. There are very few grasses that have solid stems. To be certain that the stem is hollow, cut it open between the nodes (grass illustration). If the specimen has a solid stem, it is not likely a grass. Peel back the leaves (if there are any) and note whether the stem is round, that is if it easily rolls between your fingers, or whether it angular. Plants with angular stems are usually sedges, those with round stems are rushes. Hence the simple maxim is . . . "rushes are round and sedges have edges (sedge illustration). Technically speaking the Sedge family (Cyperaceae) has many genera, not all of which have angular stems. The "sedges have edges" character applies mostly to true sedges in the genus Carex. Many bulrushes or tules in the genus Scirpus have round stems. To be certain that a plant that is a member of the Sedge Family you must examine the flower. The individual flowers are borne in the axil (inside face) of a single, scalelike bract. This contrasts with grasses that have two bracts immediately associated with the individual flower (lemma and palea). Sedges and grasses have one seed for each flower, in contrast to the rushes which have a three-parted capsule filled with many small, black seeds. Rushes (Juncus) and wood rushes (Luzula) in the Rush Family (Juncaceae) have solid stems as mentioned. The flowers usually consist of two series of three, petal-like structures, which are actually the sepals and the petals that surround the pistil (rush illustration). Using a hand lens you can see that these look like the petals of a miniature brownish lily.
|
 |
||
 |
Copyright © Royal
BC Museum |
|
