492 PART IV. CLASSIFICATION. 



T. vulgare, the common Wheat, with long glumes, which have no keel, 

 and T. turgidum, English Wheat, with short keeled glumes; T. compact/tin. 

 the D\varf Wheat, with short, stout spikelets; and T. durum, the Hard 

 Wheat, known by its long rigid awns ; all these varieties have a wiry 

 floral axis (hence sometimes described as T. satimtm tenax), and the fruit 

 easily falls out of the glumes, and in all but T. durum there are awned 

 and un-awned (beardless) forms: T. spelta, the Spelt, which has an almost 

 quadrangular spike, and T. dicoccum', with a compact spike, have a brittle 

 floral axis, and the fruit is firmly enclosed by the glumes. In all the 

 species the length of the awn varies very much. Hordeum, the Barley, 

 has 3 single-flowered spikelets inserted together in one depression on the 

 floral axis. H. murinum is common on the roadside and on walls. The 

 following varieties of H. sativum are cultivated: H. vulyare and H. hexa- 

 stichum, with only fertile spikelets; in the latter species the spikelets are 

 all equally distant, and are therefore arranged in six rows ; in the former 

 species the median spikelets are nearer together, and the lateral ones more 

 distant, so that they are described as being in four rows : further, H. 

 distichum is the two-rowed Barley, the lateral spikelets of which are <?, 

 so that the fruits are arranged in two rows. The fruit usually adheres to 

 the palea. The genus Elymus, the Lyme-Grass (E. arenarius, British) 

 belongs to this tribe, as also Pariana, a tropical genus remarkable for its 

 numerous stamens. 



Tribe 11. Bambusece : spikelets 2- or many-flowered, rarely 1- flowered, 

 in racemes or panicles, clustered at the nodes of the branches of the in- 

 florescence: glumes 2 or many, becoming larger upwards, but shorter than 

 the nearest palea : stamens generally 6 (see Fig. 299 A). Large Grasses, 

 known as Bamboos, having perennial aerial shoots with often shortly 

 petiolate leaves, growing mostly in the Tropics. The most familiar genera 

 are Arundinaria and Bambusa. 



Order 2. CYPERACE^E. The leaves are arranged in three rows 

 on the stem : perianth 0, or of 3-6 or more bristles or scales : the 

 androecium consists typically of two trimerous whorls, though 

 one whorl (the inner) is absent in some genera : the gynaeceum 

 is typically trimerous, though it is sometimes dimerous : ovary 

 unilocular:. ovule erect, anatropous: the embryo is enclosed in the 

 endosperm. 



Tribe 1. Scirpoidece : flowers $ ; perianth 0, or of bristles : glumes disti- 

 chous: the odd carpel is anterior. The spikelets are often arranged so as 

 to form spikes, panicles, umbels, or capitula : the flower has the formula 

 #3, C3, ,48+0 or 3, G. 



Cyperus, the Galingale, has many-flowered compressed spikelets with 

 deciduous bracts or glumes: Schoenus, the Bog-Rush, has few-flowered 

 (1-4) spikelets with persistent glumes : C. tonyus and fuscus, and S. nigri- 

 cans, occur in England. Cyperus Papyrus (Papyrus Antiquorum) is an 

 Egyptian species from which the Papyrus of the ancients was made. 



