TYPE 10. GRAINS SIMPLE, STRUCTURE OBSCURE. 243 



Cham fwtida A. Eraun. Fresh spores. — Grains usually triangular, rarely quadrangular, oval, rcmi- 

 forni or irreguhir; 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, so that when viewed on end the grain appears conic;il or pear-shaped; wthout 

 lamellic or hilum; from the broad aspect a delicate curvetl slit is observed, from the center 

 of which several short fissures may radiate. Size about 20ju. 



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

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

 pressed to half their width; from the narrow aspect a distinct slit, anil 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^. 



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 IGju. 



Chara alopecuroides Willd. Dry spores. — Grains reniform, or 3, rarelj' 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 22/i. 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 25/^; Chara barbata Meyen, size about 20/^; Chara frayilis Dcsv., 



size about 17;u; Chora contraria A. Braun., size about 20/i; Chara gymnophylla A. Braun, size 



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

 Isoeles lacustris Linn. (Isoetacece.) Dry gymnospores. — Grains spherical, rarely somewhat irregular. 



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

 Pinus sylveslris Linn. {Coniferce.) Dry pollen. — Grains oval to pear-shaped. Size about ^ix. Poor 



in starch and rich in oil. 

 Avcna pubescens Liim. {Graniinacea;.) Fresh pollen. — Grains rounded, oval, pear-shaped. Size 



about ^.bn. Starch plentiful. 

 Bromus mollis Linn. {Graminacew.) Fresh pollen. — Grains as in preceding. Size about G/x. Starch 



plentiful. 

 Alpinia nutans Rose; Globba nutans. (Zingibcracea;.) 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 IS^i. Starch jilentiful in the large pollen-grains; lacking in the 



smaller ones. 

 Naias major Roth. (Naiadacew.) 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 7.5^. Starch plen- 

 tiful. 

 Ruppia maritima Linn. (NaiadacecB.) 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. 

 Syringa imlgaris Linn. {Oleacew.) Fresh pollen. — Grains rounded. Size hardly 3ju. Starch less 



plentiful than oil. 

 Veronica chamcedrys Linn. (Scrophulariaccce.) Fresh pollen. — Grains rounded, oval, pear-shaped. 



Size about 6/u. Starch plentiful. 

 Ranunculus bulbosus Liim. {Ranunculaccce.) Fresh pollen. — Grains rounded. Size at most 3/i. 

 Viola cornuta Linn. (Violaceoe.) Fresh pollen. — Grains rounded, oval, pear-shaped. Size about i/x. 



Starch plentiful. 

 Geranium molle Linn. (Geraniacece.) Fresh pollen. — Grains more or less rounded. Size about 3^. 



Starch quite plentiful. 

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



about 5/1. Similar grains are found in the cell-lumen and in the cell-tissues. 



