208 DIFFEHENTIATION AND SPECIFICITY OF STARCHES. 



(2) Small grains rounded, more often oblong or oval ; usually distinctly convex at one end and 

 less so or somewhat concave at the other; occasionally reniform or triangular; the wide 

 forms are slightly compressed. Size 4 to 30/:. The classification of these grains is somewhat 

 uncertain. The lamellae of the spherical grains arc mathematically centric. The structure of the 

 large oval grains agrees with that of the Leguminosce. The smaller grains resemble the largest 

 in form at least, but the almost central hilum seems to be more spherical. Perhaps the larger 

 and smaller grains of Leguminosce also differ as in the case with the seeds oiChara. Among 

 the grains described doublets occur which are composed of one large and one small component. 



Marsilca pubescens Ten. {Marsiliacccc.) Dry gymnospores. — Grains oval, or rounded triangular 

 to oblong, and pear-shaped, at times somewhat irregular; the wider ones compressed to about 

 one-half; hilum oblong, lamellse distinct, frequently vnth a longitudinal slit that is seen 

 distinctly in the narrow side, and from which cross-fissures frequently radiate. Length 30 

 to 110/i, width CO/i, thickness 35^. Amoiig them some compound grains (type 11). 



Marsilca pubescens Ten. {Marsiliaceoe.) Dry androspores. — Grains elliptical, rounded-triangular to 

 oblong, and pear-shaped; two-thirds to as broad as long, to 4 times as long as thick, the 

 broader ones compressed to about one-third; sometimes with a slit seen in the narrow aspect. 

 Length 10^, breadth 7fi. 



Globularia pilulifera Linn. {Globular isaccce.) Dry androspores. — Grains rounded, or rounded-tri- 

 angular to oval, or pear-shaped; compressed to about one-half or more; a longitudinal slit 

 in the narrow aspect. Size lii. 



Butomus umbellatus Linn. (Alismacece.) Dry embryo. — Grains rounded, reniform to oval, and pear- 

 shaped; the wider ones compressed to about one-half; a longitudinal slit on the narrow aspect. 

 Leng-t,h IV, width 10/i. The grains closely approach the centric-lenticular type (type 2). 



Limnocharis plumicri Rich. (Alismocece.) Dry embryo. — Grains circidar to oval, occasionally some- 

 what irregular; compressed to about one-half the width, without lamella; frequently with 

 distinct hilum; on the broad aspect, usually with 2 to 7 marked fissures radiating from the 

 center to the margin; a lengthwise slit is often seen on the narrow side. Length 21/i, \vidth 

 llfj., thickness 8^. The grains approach type 2. 



Philydrum lanuginosum Gaert. (Philydacece.) Dry seed. — Grains elliptical or ovoid, sometimes 

 almost reniform, frequently somewhat irregular; one-half to equally as liroad as long; some- 

 times slightly compressed; no lamellse; usually with an indistinct slit which in the compressed 

 grains coincides with the greatest plane, and from which indistinct cross-fissures sometimes 

 radiate. Length 22/i, breadth 14ju, thickness 12/i. Doublets and triplets are often found. 



Reussia trijlora Endl. {Pontedcriacew.) Dry seed. — Grains oval to lanceolate, very often more or 

 less curved, usually elliptical or spindle-shaped, sometimes drawn into sharp points, and more 

 or less regular; 1.5 to 4 and 6 times as long as broad; the broad ones compressed, the smaller 

 ones terete; no lamella;; an indistinct longitudinal slit is seen in the narrow, and at times 

 also in the broad aspect. Length 30 to 45//. A few compound grains have small number 

 of part-grains. 



Helcranlhera limosa Vahl. (Ponicderiaccoe.) Dry seed. — Grains elliptical to oblong, usually some- 

 what curved or reniform, sometimes triangular, and frequently irregular with protruding 

 angles or humps; occasionally pointed at one or at both ends; 1.33 to 3 times as long as broad; 

 the broader ones compressed; with a central cavity or fissure. Length 16 to 22ix, breadth 

 lO/i, thickness 8^. The grains resemble those of Reussia, but are shorter, more compact, 

 and more torulose. 



Pontcdcria sp. (Pontedcriacecc.) Dry seed. — Grains as above, but shorter, less pointed, and more 

 polyhedral. 



Eichhornia tricolor M. Seubert. (PontedcriacecE.) Dry seed. — Grains as in Pontederia. 



Slratiotes aloides Linn. (Hydrocharitacem.) Dry embryo. — Grains elliptical, oblong, rarely curved, 

 or almost reniform; 1.5 to 3 times as long as thick; the majority compressed; usually with a 

 longitudinal slit seen in the nai-row aspect. Length about 13^, thickness about 8^. 



Damasonium indicum Willd. ; Oltelia alismoides Pers. (Hydrocharitacece.) Dry embryo.— Grsdna oval 

 or elliptical, frequently somewhat kidney-shaped; one-half to almost equally as broad as long, 

 the broad ones laterally compressed to about one-half, the narrow ones slightly or not at all 

 compressed; no lamellae; frequently with a longitudinal slit on the narrow aspect. Length 

 about 20 to 27/i, breadth 18ju. The grains approach the centric-lenticular form (type 2). 



