The _spikelets_ are 1- to 2-flowered in dissimilar pairs, one globose, sessile and bis.e.xual and the other ovate, pedicelled, neuter; the pedicel is adnate to the joint of the rachis.
The _sessile spikelet_ has four _glumes_. The _first glume_ is hard, globose, foveolate, with an oblong opening, faintly nerved. The _second glume_ is chartaceous, immersed in the cavity of the joint, and filling the opening. The _third glume_ is small hyaline and empty. The _fourth glume_ is hyaline, small and paleate. The grain is sub-globose.
_Lodicules_ are broadly cuneate.
The _pedicelled spikelets_ also have four _glumes_. The _first glume_ is ovate, sub-chartaceous, winged on one side with a broad hyaline ciliate wing, 5- to 7-veined. The _second glume_ is cymbiform, compressed laterally, with a dorsal hyaline ciliate wing to the keel, 5- to 7-veined. The _third glume_ is hyaline, membranous, oblong, 2-nerved and paleate or not, and with or without stamens. The _fourth glume_ is similar to the third, but slightly smaller, paleate and with three stamens.
This gra.s.s occurs in open loamy soils and in cultivated dry fields.
_Distribution._--Throughout India and Ceylon and also in most of the tropical countries.
28. Andropogon, _L._
The gra.s.ses of this genus are either perennial or annual and vary very much in habit. The inflorescence consists of solitary, binate, digitate, or panicled racemes. The rachis is usually jointed and fragile.
Spikelets are binate, a sessile female or bis.e.xual and a pedicelled male or neuter. The sessile spikelet is 1-flowered and has usually four glumes. The first glume is coriaceous or chartaceous, dorsally compressed, with incurved margins, usually 2-keeled. The second glume is as long as the first, thinner, with a median keel, laterally compressed, awned or not. The third glume is hyaline, empty, nerveless and without a palea. The fourth glume is hyaline, narrow or broad, 2-fid and awned, or reduced to an awn more or less dilated at the base, paleate or not.
There are two lodicules and three stamens. Stigmas are feathery. Grain is free. The pedicelled spikelets are usually smaller than the sessile and have three or four glumes and are awnless.
KEY TO THE SPECIES.
A. Sessile spikelets all similar.
B. Racemes of many spikelets.
C. Peduncle of racemes enclosed in spathiform leaf-sheaths.
D. Joints of rachis and pedicels of upper spikelets slender and tips obliquely truncate.
Racemes solitary, pedicelled spikelets similar to the sessile, glume 1 of sessile spikelets pitted. 1. A. foveolatus.
DD. Joints of rachis and pedicels of upper spikelets clavate or trumpet-shaped and tips cupular with toothed margins.
Racemes binate, pedicelled spikelets differing from the sessile, glume I of the sessile spikelets deeply channelled. 2. A. pumilus
CC. Peduncle of racemes not enclosed in spathiform leaf-sheath.
Racemes many, fascicled or panicled, glume I of sessile spikelets glabrous and pitted. 3. A. pertusus.
Racemes many and whorled in the panicle; glume I of sessile spikelets muricate on the margins. 4. A. squarrosus.
BB. Racemes of 3 spikelets on the capillary whorled branches of an erect panicle.
Pedicels of upper spikelets half as long as the sessile spikelets or longer.
Leaves broad.
Leaf-sheaths covered densely with bristly hairs. 5. A. asper.
Leaf-sheaths covered with soft hairs. 6. A. Wightia.n.u.s
Pedicels of upper spikelets not half as long as the sessile spikelet.
Leaves glabrous and narrow 7. A. monticola.
AA. The lowest one or more sessile spikelets in all racemes, or at least in one or two, differing from all those above.
Racemes digitate, rarely solitary, spikelets all alike in form but differing in s.e.x.
Pedicel 1/3 as long as the sessile spikelets; nodes usually glabrous; ligule usually short and membranous. 8. A. caricosus.
Pedicel 1/2 as long as the sessile spikelets; nodes bearded; ligule large and membranous. 9. A. annulatus.
Racemes solitary; lower sessile spikelets very unlike the pedicelled or upper spikelets which are cylindric.
Margin of glume 1 of the pedicelled spikelet unequally winged; ligule is a broad truncate membrane. 10. A. contortus.
Racemes two, both sessile, or one sessile and the other pedicelled on a peduncle which is more or less sheathed by a proper spathe, divaricate or deflexed.
Leaf base broad and cordate 11. A. Schoenanthus.
_N.B._--This genus is now split into several separate genera, each subgenus being raised to the rank of a genus. But in this book the nomenclature adopted in Hooker"s Flora of British India is followed.
[Ill.u.s.tration: Fig. 148.--Andropogon foveolatus.]
=Andropogon foveolatus, _Del._=
The stems are slender at first, slightly dec.u.mbent at the base and then erect, covered at base with silkily villous sheaths, branches freely above before flowering, the lower portion of stems alone being leafy.
The _leaf-sheath_ is somewhat scaberulous, partly green and partly purplish, always shorter than the internode. The _ligule_ is short, truncate, hyaline and ciliate. _Nodes_ are tumid and purplish with a ring of hairs.
The _leaf-blade_ is linear, narrow, sometimes even filiform, ac.u.minate slightly cordate at the base, scabrid throughout with a few scattered long bulbous-based hairs near the base to a distance of less than 1/2 inch about it and varies from 2 to 4 inches in length.
[Ill.u.s.tration: Fig. 149.--Andropogon foveolatus.
1 and 2. Sessile and pedicelled spikelets; 3, 4, 5 and 6. the first, second, third and the fourth glume, respectively, of the sessile spikelet; 7. lodicules, anthers and ovary; 8, 9 and 10. the two glumes and the palea of the pedicelled spikelet.]
The _spikes_ are solitary, 1 to 1-3/4 inch long exserted far above the small spathiform leaf-sheaths, peduncles are capillary and scaberulous, pedicels and joints are somewhat flattened, and have along both the narrow margins long, white, ascending hairs; callus is short with a ring of short white hairs.
There are two kinds of _spikelets,_ sessile and pedicelled, and both are oblong-lanceolate and equal. The _sessile spikelet_ consists of _four_ _glumes_. The _first glume_ is lanceolate, flat and smooth, keels scabrid with usually a deep dorsal pit, 4-nerved. The _second glume_ is lanceolate, acute, as long as the first, 3-nerved. The _third glume_ is small, membranous, linear-lanceolate, nerveless. The _fourth glume_ is the dilated base of the awn, awn is about 3/4 inch twisted to half its length, scabrid, the lower twisted part dark and the upper pale. There are three _stamens_ and two _lodicules_. _Ovary_ has two feathery _stigmas_. The _pedicelled spikelets_ have only two glumes and contain three stamens. The _first glume_ is oblong-lanceolate, 5-nerved, pitted above the middle, with recurved margins and scabrid keels and nerves.
The _second glume_ is lanceolate, membranous, hairy at the top, 3-nerved with margins infolded; _palea_ is oblanceolate, thinly membranous, nerveless and ciliated at the top; there are three _stamens_ and two _lodicules_.
This is a fairly common gra.s.s occurring all over the Presidency much liked by cattle and yields plenty of foliage if properly looked after.
It grows on all kinds of soils, even laterite.
_Distribution._--Throughout India.
[Ill.u.s.tration: Fig. 150.--Andropogon pumilus.]