TYPE 10. GRAINS SIMPLE, STRUCTURE OBSCURE. 243 



Chara fcrtida A. Briiuii. Fnsh spores. Grains usually triangular, rarely quadrangular, oval, reni- 

 form or irregular; compressed to one-half or more of their width; one border, straight or 

 concave, and thinned into a more or less knife-like edge; the other strongly convex and 

 thickened, .'^o that when vioweil on end the grain appears conical or pear-shaped; wthout 

 lanielkc or hilum; from the broad aspect a delicate curved slit is observed, from the center 

 of which several short fissures may radiate. Size about 20/u. 



Cham hispida Linn. Dry spores. Grains rounded; oval, frequently reniform or triangular with 

 roundcnl angles; usually less dense at the straight or concave border; the broad ones com- 

 pressed to half tlu'ir wiilt h ; from the narrow aspect a distinct slit, and from the broad longi- 

 tudinal aspect a delicate slit is observed; the latter, in the reniform and triangular grains, is 

 curved toward the convex margin. Size 16 to 25,u. 



Chara aspera Willd. Dry spores. Grains usually triangular or reniform, sometimes oval or irreg- 

 ular; scarcely half to almost as broad as long; shortened to two-fifths of their length, one 

 side of the margin usually strongly convex and thickened, the other, slightly convex, straight, 

 or concave and thinned to a knife-like edge; occasionally from the broad aspect with a very 

 delicate curved and somewhat eccentric slit; from the narrow aspect a somewhat more 

 marked, straight median slit. Size about 16/i. 



Chara alopeciiroides Willd. Dry spores. Grains reniform, or 3, rarely 4 to 5, angles; usually almost 

 as broad as long; compressed to one-half or over their width; thicker on one edge than on 

 the other. Size about 22fi. Among these there are smaller grains, which have one thick- 

 ened convex and one sharpened more concave edge, as in Chara aspera. 



The following species of Chara have grains similar to those already described above, namely: 

 Chara baiieri A. Braun, size about 25jli; Chara barhata Meyen, size about 20^; Chara fragilis Desv., 



size about 17/^; Chara conlraria A. Braun., size about 20/;; Chara gymnophylla A. Braun, size 



about 21/^; Chara coronata Zig., size about 18^. These were all examined in the dry state. 

 Isoetes lacustris Linn. {Isoetacew.) Dry gyninospores. Grains spherical, rarely somewhat irregular. 



Size about 8yu. Starch not plentiful, embedded among oil-bodies and plastids. 

 Pinus sylvestris Linn. (Coniferm.) Dry pollen. Grains oval to pear-shaped. Size about ifi. Poor 



in starch and rich in oil. 

 Avena puhescens Linn. {Graminacece.) Fresh pollen. Grains rounded, oval, pear-shaped. Size 



about 4.5At. Starch plentiful. 

 Bromus mollis Linn. {Graminacece.) Fresh pollen. Grains as in preceding. Size about 6ju. Starch 



plentiful. 

 Alpinia nutans Rose; Globba nutans. (Zingiberacece.) Pollen. According to Payen (Ann. Sc. 



Nat., 1838, p. 26, pi. 5, fig. 4), the grains are oblong; .sometimes curved, about 3 times as 



long as broad. Size about 15/i. Starch plentiful in the large pollen-grains; lacking in the 



smaller ones. 

 Naias major Roth. (Naiadacece.) Pollen. According to Payen {loc. cit., p. 28, pi. 5, figs. 5 and 6) 



and Fritsche (Ueber den Pollen, Taf. iii, fig. 5), the grains are oval to almost cylindrical, 



more or less curved, and about 2 to 3 times as long as broad. Size about 7.5yu. Starch plen- 

 tiful. 

 Ruppia maritima Linn. {Naiadacem.) Pollen. According to Payen (loc. cit., p. 27, pi. 3, fig. 25), 



the grains are rounded or oval, more or less irregular, occasionally cylindrical with rounded 



ends, more or less crooked. Size about 11^. Starch plentiful. 

 Syri7iga vulgaris Linn. (Oleaceoe.) Fresh pollen. Grains rounded. Size hardly 3m. Starch less 



plentiful than oil. 

 Veronica chamwdrys Linn. {Scrophulariacew.) Fresh pollen. Grains rounded, oval, pear-shaped. 



Size about 6^. Starch plentiful. 

 Ranunculus bulbosus Linn. {Ranuncidacece.) Fresh pollen. Grains rounded. Size at most 3^. 

 Viola cornuta Linn. (Violacew.) Fresh pollen. Grains rounded, oval, pear-shaped. Size about 4/i. 



Starch plentiful. 

 Geranium molle Linn. {Geraniacem.) Fresh pollen. Grains more or less rounded. Size about 3^. 



Starch quite plentiful. 

 Geranium pratense Linn. {Geraniacece.) Fresh pollen. Grains rounded, oval, pear-shaped. Size 



about 5m. Similar grains are found in the cell-lumen and in the cell-tissues. 



