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Manual of the New Zealand Flora.
20. Deschampsia, Beauv
20. Deschampsia, Beauv.
Perennial grasses. Leaves narrow, flat or convolute. Spikelets rather small, 2-flowered, arranged in lax or contracted panicles; rhachilla disarticulating above the 2 outer glumes, produced between the flowering glumes and above the upper flower as a naked or hairy bristle, rarely ending in an imperfect flower. Glumes 4; 2 outer slightly unequal, persistent, empty, keeled, acute, membranous, shining; 3rd and 4th (or flowering glumes) membranous or page 875almost hyaline, toothed at the apex dorsal awn slender, twisted at the base, sometimes very small or wanting. Palea narrow, 2-nerved. Lodicules 2, ovate. Stamens 3. Styles distinct; stigmas plumose. Grain oblong, enclosed within the unaltered flowering glume and palea.
Species about 25, dispersed through most cold or temperate regions. One of the New Zealand species extends through the whole range of the genus; the remaining 6 are endemic. These constitute a somewhat anomalous group, differing from the true Deschampsiæ in the awn being almost terminal and very small, or altogether absent. They may ultimately form a separate genus.
* Awn from the middle of the back of the flowering glume or below it.
Tall, 1–4 ft. high. Panicle long, 4–12 in. Spikelets ⅕–¼ in.1. D. cœspitosa.
** Awn from immediately below the tip of the flowering glume or wanting.
† Rhachilla glabrous.
Forming dense patches ½–1 ½ in. high. Leaves short, curved. Panicle ¼–¾ in., dense. Spikelets straw-yellow, shining. Awn wanting or rarely present 2. D. pusilla. Slender, 3–9 in. Leaves shorter than the culms, involute. Panicle slender, lax, 1–3 in. long. Spikelets pale-green, apex of flowering glume irregularly denticulate. Awn wanting 3. D. novœ - zealandiœ. Slender, 6–18 in. Leaves flaccid, flat or involute, often capillary. Panicle very slender, 3–6 in. Spikelets 1/10–⅛ in., pale-green; apex of flowering glume 3-toothed. Awn usually present 4. D. Chapmani. † Rhachilla hairy.
Very slender, flaccid, 6–14 in. Leaves capillary. Panicle very slender, lax, 2–6 in. Spikelets small, 1/10 in.; apex of flowering glume 3-toothed. Awn usually present 5. D. tenella. Slender, tufted, 2–8 in. Leaves short, strict. Panicle lax, deltoid, ¾–2 in. Spikelets few, ⅓–⅙ in.; apex of flowering glume 3-toothed. Awn usually present. Hairs of rhachilla long, copious 6. D. gracillima. Slender, 3–6 in. Leaves short, flat. Panicle sparingly branched, lax, 1–2 in.; spikelets few. Flowering glume irregularly denticulate awn wanting. Rhachilla with a minute empty glume at the apex 7. D. penicillatca.
| 1. | D. cæspitosa,Beauv. Agrost. 91, t. 18, f. 3.—Culms densely tufted, forming large tussocks, smooth, shining, rather stout or slender, leafy, 1–4 ft. high. Leaves rather stiff, narrow, flat or convolute, rough on the upper surface and margins; sheaths shining, smooth or rough; ligules long, membranous, acute. Panicles 4–12 in. long, usually rather narrow and dense in New Zealand examples, inclined or nodding above; branches in somewhat; distant fascicles, capillary, smooth or minutely scaberulous. Spikelets ⅕–¼ in. long, shining, pale yellow-green or purplish. Two outer glumes keeled, acute or subacute, 1-nerved or the upper page 8763-nerved; 3rd and 4th or flowering glumes equalling the empty glumes or rarely exceeding them, truncate, 4-toothed, silky at the base, the 4th separated from the 3rd by a distinct hairy internode, sometimes absent so that the spikelet becomes 1-flowered; awn from the middle of the back or below it, not twisted at the base or obscurely so, usually not far exceeding its glume. Rhachilla produced into a distinct hairy pedicel above the 4th glume.—Hook. f. Fl. Nov. Zel. i. 301; Fl. Tasm. ii. 118; Handb. N.Z. Fl. 334; Benth. Fl. Austral. vii. 587;Buch. N.Z. Grasses, t. 37. Aira cæspitosa, Linn. Sp. Plant. 64. A. Kingii, Hook. f. Fl. Antarct. ii. 376, t. 135. A. australis, Raoul, Choix, 12. Agrostis aucklandica, Hook. f. Fl. Antarct. i. 96.
North and South Islands, Stewart Island, Chatham Islands, Auckland Islands Wet places from the Lower Waikato southwards, plentiful. Sea-level to 3500 ft. An abundant grass in all cool and temperate regions. The New Zealand form has the spikelets rather larger and the awn of the flowering glume inserted somewhat higher up than is usual in northern specimens, and is distinguished as var. macrantha by Hackel. |
| 2. |
D. pusilla,Petrie in Trans. N.Z. Inst. xxiii.(1891) 403.—Culms densely tufted, branched at the base, 1–2 in. high, forming small compact patches. Leaves numerous, shorter than the culms, setaceous, curved, convolute; sheaths broad, membranous, grooved; ligules large for the size of the plant, acute, much broader than the blade, decurrent along the margins of the sheath. Panicle small, contracted, sometimes almost spiciform, straw - yellow, shining, ¼–¾ in. long; branches few, short, small, the lowermost bearing 2–3 spikelets, the upper 1 only. Spikelets ⅛in. long, 2-flowered, rarely 3-flowered. Two outer glumes almost equal in length, hyaline, the lower narrower, 1-nerved, the 2nd 3-nerved; 3rd and 4th or flowering glumes faintly silky or almost glabrous at the base, broadly oblong, hyaline, indistinctly 5-nerved, truncate, irregularly 3-toothed or erose, awnless or with a minute dorsal awn inserted just below the tip. Palea as long as the glume, deeply bifid, 2-nerved. Rhachilla elongated between the flowering glumes and produced beyond the upper flower into a short bristle, quite glabrous. South Island Otago—Hector Mountains, Petrie!Humboldt Mountains, Cockayne! 5000–6500 ft. A very remarkable little plant, quite distinct from any of the following species. |
| 3. | D. novæ-zealandiæ,Petrie in Trans. N.Z. Inst. xxiii. (1891) 402.—Culms densely tufted, branched at the base, slender, smooth, leafy below, 3–9 in. high, rarely more. Leaves from ⅓to ½the length of the culms, very narrow, setaceous, involute; sheaths page 877broad, pale, membranous, grooved; ligules long, scarious, acute, broader than the blade at the base. Panicle slender, erect, 1–3 in. long, usually lax but sometimes contracted; branches few, capillary, smooth or minutely scaberulous, sparingly divided. Spikelets few, small, 1/10–⅛ in. long, pale-green, shining, 2-flowered. Two outer glumes unequal, the lower about ½ the length of the spikelet, oblong-lanceolate, acute, 1-nerved, the upper about ⅔ the length of the spikelet, broader and more obtuse, 3-nerved 3rd and 4th or flowering glumes broadly oblong, hyaline, membranous, faintly 3–5-nerved, quite glabrous at the base, broadly truncate at the apex and irregularly minutely denticulate, awn wanting. Palea bifid, 2-nerved, nerves faintly ciliate. Rhachilla elongated between the flowering glumes and produced beyond the upper flower into a slender bristle, quite glabrous.—D.Hookeri, Kirk in Journ. Bot. xxiv. (1891) 237 (in part).
South Island Canterbury—Lake Lyndon, Petrie!Castle Hill, Kirk!Poulter River, Cockayne.Westland—Kelly's Hill, Petrie! Cockayne!Otago—Naseby, Pembroke, Mount St. Bathan's, Hector Mountains, Lake Te Anau, Petrie! 1000–5000 ft. Although very closely allied to D. Chapmani and D. tenella this appears to be sufficiently distinct from both in the irregularly denticulate apex of the flowering glume and the total absence of the dorsal awn. Mr. Kirk united all three under the name of D. Hookeri. |
| 4. | D. Chapmani, Petrie in Trans. N.Z. Inst. xxiii. (1891) 401.—Culms tufted, branched at the base, quite smooth, leafy, 6–18 in. high. Leaves longer or shorter than the culms, very narrow, flat or involute, often almost filiform, flaccid; sheaths long, narrow, deeply grooved; ligules elongated, acute, broader than the blade at the base. Panicle very slender, 3–6 in. long or more, effuse or contracted, laxly and sparingly branched branches capillary, minutely scaberulous, usually trichotomously divided. Spikelets few, small, about ⅛ in. long, pale-green, glistening, 2-flowered. Two outer glumes unequal, much shorter than the spikelet, oblong-lanceolate, membranous, the lower short, 1-nerved, the upper ½ longer, equalling the lower flower or slightly exceeding it, 3-nerved; 3rd and 4th or flowering glumes broadly oblong, membranous, faintly 3–5-nerved, glabrous at the base or rarely with few very short hairs, truncate at the apex and more or less irregularly 3–5-toothed; awn usually present on both glumes, from the back a little distance below the tip. Palea bifid, 2-nerved, nerves ciliate. Rhachilla elongated between the flowering glumes and produced beyond the upper flower into a slender bristle, quite glabrous.—D.Hookeri, Kirk in Journ. Bot. xxiv. (1891) 237 (in part).Catabrosa antarctica, Hook. f. Fl. Antarct. i. 102, t. 56. Triodia antarctica, Benth. in Journ. Linn. Soc. xix. (1881) 111.
South Island Canterbury—Arthur's Pass, Kirk!Otago—Clinton Saddle, Petrie!Milford Sound, Kirk! Auckland and Campbell Islands, Antipodes Island: Hooker, Kirk!Sea-level to 3500 ft. page 878Very close to the following species, of which it may prove to be a variety, and from it is mainly separated by the glabrous rhachilla and rather larger spikelets. |
| 5. | D. tenella, Petrie in Trans. N.Z. Inst. xxiii. (1891) 402.—Culms tufted, branched at the base, extremely slender, flaccid, quite smooth, leafy throughout, 6–14 in. high. Leaves bright-green, very narrow, capillary, involute, flaccid, the uppermost often exceeding the young panicle; sheaths smooth, grooved; ligules long, acute, membranous, broader than the blade and decurrent along the margins of the sheaths. Panicle very slender, 2–6 in. long, contracted at first, but becoming lax and somewhat effuse; branches in pairs, few, rather distant, capillary, scabrid, trichotomously divided. Spikelets few towards the tips of the branches, small, 1/10 in. long, pale, glistening, 2-flowered. Two outer glumes unequal, much shorter than the spikelet, membranous, 1-nerved or the upper 3-nerved; 3rd and 4th or flowering glumes broadly oblong, delicately hyaline, faintly 5-nerved, silky at the base, truncate at the apex and 3-toothed, the middle tooth often bifid, the 4th always with a minute dorsal awn inserted just below the apex, the 3rd frequently awnless. Palea bifid, 2-nerved, the nerve finely ciliate. Rhachilla elongated between the flowering glumes and more or less silky, produced above the upper flower into a silky bristle.—D.Hookeri, T. Kirk in Journ. Bot. xxiv. (1891) 237 (in part).Catabrosa antarctica, Hook. f. Fl. Nov. Zel. i. 308 (but not of Fl. Antarct. i. 102); Buch. N.Z. Grasses, t. 41B.
North Island Ruahine Mountains, Colenso!Tararua Mountains, H. H. Travers!South Island: Nelson—Mount Arthur, A. McKay!Otago—Near Dunedin, Catlin's River, Clinton Saddle, Petrie!Sea-level to 4500 ft. This differs from both D. novæ-zealandiæ and D. Chapmani in the silky rhachilla, and from the former in addition in the dorsal awn being present in at least the upper flower. It varies greatly in the size of the spikelets and in the proportionate length of the outer glumes. Mr. Petrie's original specimens from Catlin's River have the spikelets barely more than 1/12 in. long, and the upper outer glume is not half the length of the spikelet; but those from the Clinton Valley, and Mr. Colenso's from the Ruahine Range, have much larger spikelets with longer outer glumes. |
| 6. | D. gracillima,T. Kirk in Journ. Bot. xxiv. (1891) 237.—Culms tufted, usually with intravaginal branches near the base, erect, slender, glabrous, 2–8 in. high. Leaves towards the base of the culms and much shorter than them, strict, erect, very narrow, setaceous or filiform, convolute; sheaths rather lax, grooved; ligules long, membranous, usually split at the tip. Panicle erect, ovate or deltoid, open, ¾–2 in. long; branches few, binate, capillary, smooth or almost so. Spikelets ⅛–⅙ in. long, on pedicels longer than themselves, 2-flowered. Two outer glumes unequal. 3-nerved, shorter than the spikelet; 3rd and 4th or flowering glumes densely page 879silky at the base, oblong, membranous, 5-nerved, truncate at the tip and 3-toothed, the middle tooth entire or bifid or irregularly erose, the 3rd awnless or very obscurely awned, the 4th usually with a minute dorsal awn inserted just below the tip. Palea linear-oblong, bifid, 2-nerved, nerves finely ciliate. Rhachilla elongated between the flowering glumes and densely silky, produced above the upper flower into a long silky bristle.
Auckland Islands Carnley Harbour, altitude 1000 ft., Kirk! The densely tufted habit, short strict erect leaves, deltoid few-flowered panicle, large spikelets, and densely hairy rhachilla distinguish this from all its allies. |
| 7. | D. penicillata,T. Kirk in Trans. N.Z. Inst. xxvii. (1895) 354.—Culms tufted, slender, glabrous, leafy, 3–6 in. high. Leaves shorter than the culms, radical and cauline blades short, ¼–1½in. long, narrow, flat or involute, striate sheaths pale, membranous, deeply grooved, the uppermost long, enclosing the culm up to the base of the panicle; ligules long, pointed, scarious, broader than the blade at the base. Panicle small, 1–2 in. long, few-flowered; branches few, capillary, the lower ones bearing 2–3 spikelets, the upper 1 - spiculate. Spikelets ⅛–⅙ in. long, pale yellow-green, shining, 2-flowered. Two outer glumes almost equalling the flowering glumes, subequal, oblong-lanceolate, subacute, hyaline, 3-nerved 3rd and 4th or flowering glumes oblong, very delicate, with white hyaline tips, 5-nerved, silky at the base, obtuse or almost truncate at the tip and irregularly minutely denticulate, awn wanting. Palea linear-oblong, 2-nerved, nerves silky. Rhachilla elongated between the flowering glumes and produced beyond the upper flower into a bristle bearing a minute empty glume at its summit, silky throughout.
Macquarie Island: In swamps, A. Hamilton! I regret that I have only seen two small and immature specimens of this curious little plant, which is by no means closely related to any other New Zealand species. |