Part 8

A =Tuber= is a thickened end of a rootstock, bearing buds,—“eyes,”—on its sides. The common Potato is a familiar example of a tuber, being a portion of the stem of the potato plant.

A =Corm= is a short, thick, fleshy underground stem which sends off roots from its lower face. (See Jack-in-the-Pulpit, Pl. CIV.)

A =Bulb= is an underground stem, the main body of which consists of thickened scales, which are in reality leaves or leaf bases, as in the onion.

A =Simple Stem= is one which does not branch.

A =Stemless= plant is one which bears no obvious stem, but only leaves and flower-stalks, as in the Common Blue Violet and Liver-leaf (Pl. LXXXIV.).

A =Scape= is the leafless flower-stalk of a stemless plant. (See Liver-leaf (Pl. LXXXIV.).)

An =Entire Leaf= is one the edge of which is not cut or lobed in any way. (See Rhododendron, Pl. XVI., and Closed Gentian, Pl. C.)

A =Simple Leaf= is one which is not divided into leaflets; its edges may be either lobed or entire. (See Rhododendron, Pl. XVI.; also Fig. 1.)

Fig. 1. ]

Fig. 2. ]

Fig. 3. ]

A =Compound Leaf= is one which is divided into leaflets, as in the Wild Rose, Pink Clover, and Travellers’ Joy (Pl. XXXI., also Fig. 2).

A =Much-divided Leaf= is one which is several times divided into leaflets (Fig. 3).

The =Axil= of a leaf is the upper angle formed by a leaf or leaf-stalk and the stem.

Flowers which grow from the axils of the leaves are said to be =Axillary=.

A cluster in which the flowers are arranged—each on its own stalk—along the sides of a common stem or stalk is called a =Raceme=. (See Cardinal-flower, Pl. LXXXIII.; Shin-leaf, Pl. XVIII.)

A cluster in which the flower-stalks all spring from apparently the same point, as in the Milkweeds, somewhat suggesting the spreading ribs of an umbrella, is called an =Umbel= (Pl. LXXXI.).

A cluster which is formed of a number of small umbels, all of the stalks of which start from apparently the same point, is called a =Compound Umbel=. (See Wild Carrot, Pl. XXVIII.)

A close, circular flower-cluster, like that of Pink Clover or Dandelion, is called a =Head=. (See Oswego Tea, Pl. LXXXII.; Sunflower, Pl. LVII.)

A flower-cluster along the lengthened axis of which the flowers are sessile or closely set is called a =Spike=. (See Vervain, Pl. XCII.; Mullein, Pl. LI.)

A =Spadix= is a fleshy spike or head, with small and often imperfect flowers, as in the Jack-in-the-Pulpit, and Skunk Cabbage (Pls. CII. and CIV., also Fig. 4).

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Fig. 6. ]

A =Spathe= is the peculiar leaf-like bract which usually envelopes a spadix. (See Jack-in-the-Pulpit and Skunk Cabbage, Pls. CII. and CIV., also Fig. 5.)

A leaf or flower which is set so close in the stem as to show no sign of a separate leaf or flower-stalk, is said to be =Sessile=.

A =Complete Flower= (Fig. 6) is “that part of a plant which subserves the purpose of producing seed, consisting of stamens and pistils, which are the essential organs, and the calyx and corolla, which are the protecting organs.” (Gray.)

The green outer flower-cup, or outer set of green leaves, which we notice at the base of many flowers, is the =Calyx= (Fig. 6 Ca). At times this part is brightly colored and may be the most conspicuous feature of the flower.