TYPE 3. GRAINS SIMPLE, CENTRIC, OVAL. 209 



Hydrocharis morsus-ranw Linn. (HydrocharitacecB.) Dry embryo. — Grains rounded to oval. Length 

 lO^i. A]i]iroa('hing centric-lenticular form (type 2). 



Lachnanthcs lincloria Ell. {Hwttiodoracea:.) Dry seed. — Grains elliptical to lanceolate, frequently 

 slightly curved, sometimes triang-ular or reniform, usually more or less irregular and toru- 

 lose; one-fifth to almost as broad as long; the broad ones slightly compressed ; no lamelhe; 

 with frequently a very large cavity with a longitudinal slit. Length 20 to 28;u, breadth ll;u. 

 It is doubtful whether these grains belong to this type. 



Naias major Roth.; N. marina Linn. (Naiadacea.) Dry embryo. — Grains oval, three-fifths to four- 

 fifths as broad as long; the broad ones compressed; without lamellae; a longitudinal slit from 

 which several fissures usually radiate may be seen from the narrow aspect, and sometimes 

 also from the broad aspect. Length 30,u. 



Zostera marina Linn. (Naiadacece.) Dry embryo. — Grains pressed into true polyhedrons having 

 sharp edges and angles, filling the cells like a parenchyma; one-half to as thick as long; 

 no lamellae; with fissures, which in the isodiametric grains usually radiate from a central 

 cavity and in the oblong ones proceed from a longitudinal slit at right angles to it. 

 Length 30 to 35ju. The grains approach centric-spherical (type 1). The grains in the 

 outer parts are of less size, those in the outermost lieing only 4 to Qfx. They are rounded 

 or oval, and more or less angular. These grains show very distinctly that they belong to 

 the simple tyi^e. 



Ruppia viaritima Linn. {Naiadacex.) Dry embryo. — Grains rounded to rounded-oval, frequently 

 somewhat angular; without lamellae; with a rounded, oblong, or irregular cavity, and 

 usually with irregidar radial fissures. Length 25^. Seems closely to approach the centric- 

 spherical type (type 1). Compound grains of few and usually irregular part-grains are 

 also found (type 15). 



Zannichellia pedicellata Fries. (Naiadacens.) Dry embryo. — Grains rounded to oval; half to as broad 

 as long; the broader ones compressed to about one-half and one-third their width; without 

 lamellae; longitudinal slit marked in the narrow side, also sometimes shows indistinctly in 

 the broad aspect. Length 18fi, breadth 15yu. 



Althenia filijormis Petit. {Naiadace(e.) Dry embryo. — Grains elliptical to oval, sometimes reni- 

 form; half to as broad as long; the broader ones laterally comjiresscd to about half or more 

 of their width; lamellae indistinct; longitudinal slit is seen in the narrow aspect. Length 

 18m, breadth I5ii. 



Potamogeton nalnns Linn. (Naiadacew.) Dry embryo. — Grains oval or elliptical; three-fifths to 

 three-fourths as broad as long; the broader ones conijiressed to about half their width; the 

 narrower slightly compressed; no lamellae; with a longitudinal slit on the narrow side. Length 

 30m, breadth 38m. 



Potamogeton prailongus. {Naiadacece.) Dry embryo. — Grains elliptical or oval; compressed; no 

 lamellae; sometimes with a longitudinal slit on the narrow side. Length 15m, breadth 15m. 



Calla palustris Linn. (Aroidem.) Dry seed. — Grains spherical or oval, frequently irregular; some- 

 times slightly compressed; half to as thick as long; with a small central cavity, which in the 

 spherical form is almost round, in the oval forms oblong. The grains approach the centric- 

 spherical {type 1). 



Anthurium acaule Sweet.; Pothos acaidis Linn. (Aro'idea;.) Dry seerf.— Grains spherical or oval, 

 sometimes slightly angular, due to pressure; three-fifths to as broad as long; frequently 

 with a small central cavity. Length 8 to IOm- The grains approach the centric-spherical 

 (type 1). 



CeratopJujllum svhmersum Linn. {Ceratophyllacece.) Dry cotyledons.— Grams rounded to oval; two- 

 thirds to as broad as long; slightly compressed; no lamellae; a longitudinal slit is seen on the 

 narrow side, and a delicate one is sometimes visible in the wide aspect; also simple radial 

 fissures. Length 23m, w-idth 20m. The grains approach the centric-spherical (type 1). 



Nelumbium speciosum Willd. {Nymphacem.) Dry cotyledons.— Grams oval or elliptical, sometimes 

 one margin more curved than the others, or even plano-convex, many of them with 3 or 4 

 angles; the wide ones slightly compressed; no lamella, or single and indistinct; a marked slit 

 is seen on the narrow side, less marked on the liroad aspect. Length 20m. The grains de- 

 crease in size toward the surface of the cotyledons, lumulc contains oil and starch. The 

 grains small, rounded, somewhat irregular. Size 5 to 6m. (Syn. Nelumbo nucifera G»rtn.) 

 14 



