Order 3. =Gramineæ= (=Grasses=). The stems are cylindrical, generally _hollow_ with _swollen nodes_, that is, a swelling is found at the base of each leaf which apparently belongs to the stem, but in reality it is the swollen base of the leaf. The leaves are _exactly alternate_; the sheath is _split_ (excep. _Bromus_-species, _Poa pratensis_, _P. trivialis_, _Melica_, _Dactylis_, etc., in which the sheath is not split), and the edges overlap alternately, the right over the left, and _vice versâ_; the _ligule_ is nearly always well developed. In general, the flowers are hermaphrodite; they are borne in _spikelets_ with _alternate floral-leaves_, and the spikelets themselves are borne in either _spikes_ or _panicles_. The two (seldom more) _lowest floral-leaves_ in each spikelet (Fig. 289 _øY_, _nY_) are _barren_ (as the covering-leaves in many umbels and capitula); these are termed the _glumes_. The succeeding floral-leaves, each of which supports one flower as its bract, are called the _outer pales_ (_nI_); these sometimes each bear an “awn” (a bristle-like body which projects in the median line either from the apex or the back); sometimes the upper ones are barren. Each flower has a _bracteole_, which is placed on the inside opposite the main axis; it is thin, _binerved_ or _two-keeled_, and never has an awn; it is known as the _inner pale_ (_øI_). Immediately succeeding the bracteole are: (_a_) some _small, delicate scales_ (_lodicules_, Figs. 287 _D_, 288 _C_, 290 _L_); (_b_) _three stamens_ with anthers _versatile_, so as to be easily moved, and usually notched at each end (Fig. 287 _C_); and (_c_) a simple gynœceum formed of _one carpel_ with _two styles_ having generally _spirally-branched stigmas_ (Figs. 287 _D_, 288 _C_). The ovary is _unilocular_, and contains one ascending or pendulous, anatropous ovule. _Fruit a nut_, whose seed is always _firmly united with the thin pericarp_ (“caryopsis”). The embryo is larger than in the Cyperaceæ and is placed at the base of the seed, but on the _outer convex surface_ of the pericarp (Figs. 287 _I_, 288 288 _D_, 291), _outside the endosperm_; plumule large with several leaf-primordia. On germination the cotyledon remains in the seed. The majority of Grasses are annual or perennial herbs; tree-like forms being only found in the Tropics, for example, the Bamboos; they branch (in tufts), especially from the axils of the basal-leaves, while those which are borne higher on the stem are separated by longer internodes and have no vegetative branches in their axils, though a few forms, like _Bambusa_ and _Calamagrostis lanceolata_, produce branches in these axils.