and the lower empty glumes with only one or three, or the second rarely with five nerves.

10. GAUDINIA, Beauv., two species, has the spikelets of Avena (Avenastrum); but they are singly sessile in the notches of the articulate rhachis of a single spike, thus showing the inflorescence of the tribe Hordea, to which Parlatore would remove the genus ; but the dorsal twisted awn places it much nearer to Avena, from which some authors would not generically separate it. The common G. fragilis, Beauv., is widely dispersed over the Mediterranean region. The second species, G. geminiflora, J. Gay, was proposed as a genus Arthrostachya, Link, from garden specimens of unknown origin; it has since been detected by Seubert in the Azores.

11. AMPHIBROMUS, Nees, is a single Australian species, with many-flowered spikelets. The grain is furrowed as in Avena, but glabrous and free from the palea as in Trisetum.

12. ARRHENATHERUM, Beauv., contains three European, NorthAfrican, or Oriental species, often included in Avena, but differing from that genus as well as from most Poaceae in having, as in the two following genera, the lower flower male and the upper one fertile, though the rhachilla is produced beyond it as in other Aveneæ.

13. TRISTACHYA, Nees (Monopogon, Presl), has eight species, of which two are tropical American, the remainder African, tropical or southern, one extending to the Levant. With the lower flower male, as in Arrhenatherum, they are readily distinguished by the spikelets always three together, sessile or equally pedicellate at the ends of the branches of the panicle, and by the long twisted awn of the flowering glume being terminal between two lobes or straight awns. Amongst Nees's African species, T. simplex must be transferred to Trichopteryx.

14. TRICHOPTERYX, Nees (Loudetia, Hochst.), about ten African species, of which one is also in Brazil, has the spikelets of Tristachya; but they are scattered along the branches of the panicle, not in terminal triplets. The only Brazilian species, not uncommon also in tropical Africa, T. flammea, has, as already mentioned, been rather negligently published and figured as an Arundinella, of which it has none of the characters and not much of the habit.

15. ANISOPOGON, Br., is a single West-Australian species, differing from Danthonia in the large spikelets containing only a

single perfect flower. Nees added a second species from South Africa which I have not seen; but from his description it can scarcely be a congener. Kunth has figured three lodicules in the Australian plant; I have always found only two long lanceolate ones.

16. DANTHONIA, DC., is now a polymorphous, almost cosmopolitan, genus of nearly a hundred species, of which the greater number, however, are South-African, all characterized by the spikelets containing three or more perfect flowers, and by the awn of the flowering glumes more or less twisted or bent and usually flattened at the base, but terminal between two or four teeth or straight awns. Notwithstanding considerable diversities in habit, inflorescence, and in the size and teeth of the glumes, no good natural sections have yet been proposed. Nees's Himantochate (Streblochate, Hochst.), with the lateral lobes or teeth of the flowering glumes entire and acute or awned, and Pentaschiste, with the lateral teeth bifid and one or both teeth awned, are purely artificial, and relate to the African species, all the nonAfrican ones being included in Himantochate. DeCandolle originally proposed the genus for two European species, D. procumbens and D. provincialis; Brown showed, however, that they could not well be regarded as congeners, and removed the former to his new genus Triodia. The D. provincialis therefore becomes the type of the present large genus Danthonia, though it may be somewhat anomalous when compared with the majority of the African and Australian ones. DeCandolle's chief character connecting his original species was the great length of the outer empty glumes compared with the rest of the spikelet; and this is a general, though not quite a universal, feature of the enlarged genus. Since Brown's time the following genera have been proposed, chiefly upon single species, with characters which appear to be of little more than specific value :-Pentameris, Beauv., is D. Thouarsii, Nees, from South Africa, with nearly the habit and inflorescence of D. pallescens, Nees, but remarkable for the short thick grain truncate at the top. Triraphis, Nees (not of R. Br.), is D. radicans, Steud., from South Africa, nearly allied to D. crispa, Nees. Chatobromus, Nees, contains a few South-African species, in which one, or sometimes two, of the flowers in the spikelet are imperfect. Monacather, Steud., is D. bipartita, F. Muell., an Australian species, with the fruiting glumes hardened and oblique at the base and bearing a ring of hairs under the lobes. Plin

tanthus, Steud., is founded on two Australian species, most probably of Danthonia, but which, from the evidently incorrect character given, it is impossible to identify without seeing the specimens. Crinipes, Hochst., is the Abyssinian species published by A. Richard as D. abyssinica, Hochst., in which the outer empty glumes are exceptionally shorter than the spikelet.

Tribe XI. CHLORIDEÆ.

This tribe is characterized amongst Poaceae almost exclusively by the inflorescence. The spikelets are sessile in two rows in unilateral spikes, the rhachis of which is neither articulate nor notched as in Hordees; and the spikes, sometimes solitary and terminal, are more frequently several, either digitate at the end of, or scattered along, the peduncle or axis of the single panicle. The inflorescence is thus nearly that of Paspalum, whilst the spikelets are those of Festuces, with the lowest or single perfect flower hermaphrodite, and the awns, when present, terminal and straight, not dorsal or twisted as in Agrosteæ and Aveneæ. The following twenty-seven genera are mostly, but not quite all, tropical or subtropical; the first fifteen have one fertile and only rarely a second male flower in each spikelet; the next ten have two or more fertile flowers; all, except a few very small genera or exceptional species, have the rhachilla continued beyond the flowers, and often bearing one or more empty glumes. The last three genera enumerated under the tribe are anomalous diœcious grasses, connecting Chlorides with the subtribe Sesleries of Festuces, but showing the inflorescence of the present tribe at least in the male individuals.

1. MICROCHLOA, Br., comprises three species, of which two are endemic in Africa and the third widely spread over the warmer regions of the New as well as the Old World. They are slender tufted grasses with filiform leaves and single slender terminal spikes and small awnless one-flowered spikelets without any continuation of the rhachilla.

2. SCHENEFELDIA, Kunth, is a single tropical-African species with one to four erect spikes at the top of the peduncle; the spikelets are one-flowered without any continuation of the rhachilla as in Microchloa, but not so small; and the flowering glumes bearing long capillary awns, give the spikes an elegant crinite aspect.

3. CYNODON, Pers. (Dactilon, Vill., Capriola, Adans., Fibichia,

Kæl.), a small but mixed genus, of which the typical species is a common weed in most warm or temperate parts of the civilized world. It has the slender spikes and small spikelets of Microchloa; but the spikes are several digitate at the end of the panicle, and the rhachilla is produced beyond it into a small point or bristle. Three Australian species have, however, been added to it with the spikelets of Microchloa but with the inflorescence of Cynodon, thus closely connecting the two genera. Persoon's generic name is far from being the oldest, but has been so long and so universally adopted, that the substitution of either of the others for it would only breed confusion without the slightest advantage.

4. HARPECHLOA, Kunth, has also two South-African species. The spike is single, terminal, dense, and unilateral, often falcate; and there are usually one or two male flowers above the fertile one, the glumes all unawned.

Of 5. CTENIUM, Panz. (Monocera, Ell.), we have seven species, of which four from North or South America, three from Africa or the Mascarene islands. The spikes are solitary or rarely two or even three at the end of the peduncle; the spikelets, though elegantly pectinate as in Harpechloa, have a very different structure: the second empty glume is larger than the others, and bears on the back a fine horizontal point sometimes reduced to a small tubercle; the third and fourth glumes are small and empty, or only enclose a palea; the fifth or flowering glume ends in a fine awn, and above it are one or two empty ones.

6. ENTEROPOGON, Nees, was founded on an East-Indian grass with a single long, often incurved terminal spike; otherwise very near Chloris except in some minor points. It now includes Ctenium Seychellarum, Baker, from the Mauritius, which is scarcely specifically distinct from the common East-Indian one, E. macrostachya, Munro (Chloris macrostachya, Hochst.), from Abyssinia, and an unpublished species from Mayotte in Madagascar, Boivin n. 3019, which may be thus characterized :--E. leptophylla, Benth., foliis angustissimis siccitate convoluto-subulatis, glumæ florentis integræ arista gluma ipsa longiore. The habit and the long unilateral spike are precisely those of the common Indian E. melicoides; but the leaves are very much narrower and scarcely flattened in the lower part, the spikelets rather larger, the flowering glume nearly 3 lines long, and the awn about inch, and, at least in the spikelets examined, the flowering glume is quite entire, scarcely free at the point from the awn.

7. CHLORIS, Sw., contains about forty species, dispersed over the warmer regions both of the New and the Old World. It is for the most part a natural genus, with two or more spikes digitate at the end of the peduncle, the one-flowered spikelets in two regular close rows as in the allied genera, the flowering glume usually awned, and one, two, or more empty glumes above it; but these characters are not constant, and the structure of the spikelets is somewhat polymorphous. C. monostachya, Pourr., from the Mascarene islands, and C. unispicea, F. Muell., from Australia, are slender plants with only one or rarely two spikes, and the flowering glume as well as the upper empty one are narrow and awned. In C. aciculare, Br., and C. Roxburghiana, Edgew., from East India and Australia, and C. radiata, Sw., from America and Africa, the glumes are likewise narrow and awned, or the upper empty one reduced to a mere awn, but the spikes are normally several and digitate. C. foliosa, Willd., has also a narrow awned flowering glume; but the upper empty one is a double awn (or two awnlike glumes), and the spikes are not so closely clustered at the end of the peduncle, on which account Doell has transferred the species to Gymnopogon, from which it appears to me to be much further removed. In C. pumilio, Br., C. pectinata, Benth., and C. divaricata, Br., all from Australia, the flowering glume is distinctly two-lobed with the awn between the lobes. In a considerable number of species the upper empty glumes are broad and truncate at the top-these empty glumes being several in each spikelet in the Asiatic and Australian species, but one only in the American ones. In all the preceding species the flowering and upper glumes are awned; in five or six American or African species forming the proposed genus Eustachys, Desv. (Schultesia, Spreng.), both the flowering and the upper empty glume are obtuse and truncate, but without any awn, or only a minute point. They are, however, closely connected with the typical species of Chloris through C. submutica, Kunth. C. villosa, Pers., and C. macrantha, Jaub. et Spach, both of them described in detail and figured by Jaubert and Spach, must be transferred to Tetrapogon, as having their spikelets with at least two fertile flowers.

8. TRICHLORIS, Fourn., comprises two Mexican and two extratropical South-American species. They resemble Trisetaria in their dense oblong crinite panicle and their three-awned flowering glumes; but the panicle is composed of simple crowded or verticillate spikes, and the spikelets, sessile in two rows on the rhachis