Pammel — Caryopsis and Endosperm of some Grasses. 219 

 EXPLANATION OF ILLUSTRATIONS. 



PLATES XVII-XIX. 



Sections of Phragmites communis, Oryza sativa, Glyceria 

 iluitans, Arundinaria macrosperma, Arrhenatherum , Stipa ro- 

 busla, Phleum pratense, and Dactylis glomerata, were drawn 

 to the same scale with Grunow ocular and Schrauer No. 7 

 objective. All other figures drawn to the same scale with 

 Abbe camera, Leitz objective No. 7 and ocular No. 3. The 

 two systems nearly correspond. 



Different parts of the caryopsis lettered uniformly unless 

 otherwise stated. P = pericarp, t = testa. a=aleurone. 

 s = endosperm with starch grains, cc = cuticle, n = nucel- 

 lus. gl = glume, scl = sclerotic cells. en = endosperm, 

 e = embryo, ep = epidermis. All figures original wash 

 drawings made from author's sketches by Miss King and 

 uniformly reduced in engraving. 



Plate XVII. — i, Zizania aquatica: large compound starch grains in en- 

 dosperm ; aleurone layer a single row of cells. — n, Arrhenatherum avenaceum: 

 aleurone layer of two rows of cells; starch grains compound. — in, Euchlaena 

 mexicana: starch grains solidly packed together. — iv, Oryza sativa: compound 

 starch grains; aleurone layer a single row of cells. — v, Arundinaria macro- 

 8perma: aleurone layer of more than one row of cells; compound starch 

 grains in endosperm. — vi, Hordeum jubatum: thick-walled sclerotic cells of 

 glume with short trichomes above the caryopsis; c, the nucellus only a 

 remnant. — vn, Glyceria fluitans: with compound starch grains. — vni, G. 

 aquatica; with compound starch grains. — ix, Phalaris arundinacea: testa and 

 pericarp but slightly developed; large compound starch grains. — x, Poa 

 pratensis : large compound starch grains in endosperm. — xi, Dactylis 

 glomerata: aleurone layer a single row of cells; starch grains simple. — xh, 

 Phleum pratense : lower figure, general view cross section of seed with embryo 

 in position.— xm, Stipa robusta; thick-walled cells x above testa and several 

 rows of thinner-walled cells underneath the fertile glume ; longitudinal view 

 of sclerotic cells of glume shown in upper figure ; cross section to the left 

 with an enlarged view at t'. 



Plate XVIII. —i, Triticum Spelta: simple round or elliptical starch grains 

 In endosperm. — n, T. monococcum: remnants of nucellus present. — in, 

 Bromus ciliatus var. purgans: nucellus with thick-walled stratified cells. — 

 iv, Elymus canadensis: cells of glume thick- walled, also those of nucellus, 

 but the latter not stratified. — v, Setaria italica: starch grains compressed; 

 aleurone cells small. — vi, Secale cereale: large spherical or somewhat ellip- 

 tical starch grains; nucellus a single row of cells; p', porous thickened 

 walls of pericarp. — vn, Panicum glabrum : aleurone cells small ; starch grains 

 solidly packed. — vni, Aristida ramosissima: compound starch grains in en- 



