200 DIFFERENTIATION AND SPECIFICITY OF STARCHES. 



Panicum niiliaccum Linn. (Graminacccc.) Dry seed. Grains spherical or oval-spherical, fre- 

 quently somewhat polyhedral owing to pressure; usually with small central cavity from 

 which sometimes a few fissures radiate. Size about 7ju; according to Payen, lOfi. 



Panicum acuminatum Swartz. (Graminaceae.) Dry seed. Grains angular, with rounded corners, 

 to polyhedral (filling the cells); usually with a cavity and sometimes with radial fissures, 

 giving the single grains the appearance of compound grains. Size about 12 to 15yu. 



Panicum tonsum Steud.; Tricholcena tonsa Nees. (firaminacem.) Dry seed. Grains angular with 

 rounded corners, or polyhedral with blimt, or, more often, sharp corners and edges; the 

 larger ones hollow in the center. Size about 12/i. 



Panicum hoffmannseggii R. and Sch. (Graminacew.) Dry seed. Grains angular with rounded corners, 

 or polj'hedral; frequently with large or small angular cavity. Size about lOju. 



Helopus annulatus Nees. {Graminacew.) Dry seed. Grains spherical or somewhat angular owing 

 to pressure; with central cavity from which fissures sometimes radiate. Size about 7 to 8/x. 



Pennisetum longistylum Hochst. {Graminacew.) Dry seed. Grains roundish, frequently somewhat 

 angular owing to pressure; usually with a smaller or larger central cavity from which delicate 

 short fissures radiate. Size about 15 to 20/i. 



Pennisehtm cenchroides Rich. {Graminacew.) Dry seed. Grains spherical, sometimes angular, often 

 with a central cavity and delicate radial fissures. Size about 15/x. Some have a granular 

 surface. Other seeds designated Gymnothrix cenchroides R. and Sch., have spherical to 

 rounded-oval, frequently somewhat angular, grains with central cavity and numerous fissures. 

 Size about 11^. 



Penidllaria spicata Willd.; P. pluckenetti Link; Pennisetum typhoideumRlch. {Graminacew.) Dry 

 seed. Grains usually spherical, more or less polyhedral, owing to pressure; frequently with 

 a small central cavity, rarely with radial fissures. Size about 12 to 15/^. 



Anthephora elegans Schreb.; Cencliruslwvigatus Trin.; Tripsacum hermaphroditum Linn. fil. {Gram- 

 inacew.) Dry seed. Grains spherical, usually angular owing to pressure, and sometimes 

 polyhedral with sharp corners and edges; sometimes delicate concentric lamellie; usually a 

 small, central cavity from which some or at times numerous deep fissures radiate. Size 

 about 36/Li, rarely as much as Sl^i. The grains are rarely compressed, sometimes the larger 

 ones fall to pieces. Among them are found some compound grains with few divisions, and 

 some grains that have separated. The separated grains have one hemispherical and one or 

 two plane surfaces, which distinguish them from the simple, polyhedral grains, wliich are 

 more or less flattened on all sides. 



Lappago racemosa Willd. {Graminacew.) Fresh endosperm. Grains polyhedral, with rather sharp 

 edges and angles; the larger ones hollow. Size about 9(U. Although the grains are sometimes 

 clumped together, they nevertheless appear to belong to the simple type. 



Lopholepis ornithoccphala Decsn. {Graminacew.) Dry seed. Grains angular, with rounded corners 

 to polyhedral; with, small, rarely large, usually stellate angular cavity. Size about ll^u. The 

 protoplasmic cells are crowded with starch-grains ; there are no indications of compound grains. 



Centotheca lappacea Beauv.; Cenchrus lappaceus Linn. {Graminacew.) Dry seed. Grains spherical, 

 sometimes slightly angular owing to pressure; with or without indistinct lamella'; with central 

 cavity from which fissures usually radiate. Size about 25 to 30yu. 



Beckera petiolaris Kochst. {Graminacew.) Dry seed. Grains rounded to nearly polyhedral; with 

 central cavity and radial fissures. Size about llji. 



Ampelodesmos tenax Link.; Arundo tenax Vahl. {Graminacew.) Dry seed. Grains spherical, angular 

 with rounded corners, or polyhedral; usually with small or large central cavity, and some- 

 times with radial fissures. Size about 18 to 21fi. 



Pappophonum nigricans R. Br. {Graminacew.) Dry seed. Grains circular or ovoid; the smaller 

 ones spherical; the larger ones compressed to about one-half their width; with a central 

 cavity and radial fissures. Size about 25 to 30/i. Notwithstanding the pressure facets the 

 larger grains Ijelong to the spherical rather than to the lenticular type, because they show 

 the same radial fissures in their narrow aspect as in the Ijroad one. 



Gymnopogon foliosus Nees. {Graminacew.) Dry seed. Grains angular with rounded corners to poly- 

 hedral; with a small or large square cavity or one with radial fissures. Size about 16^. These 

 starch-grains iloubtless belong to the simple spherical type. No indications of compound 

 grains were present even within tlie cells. 



