128 
IOWA ACADEMY OF SCIENCES. 
STRUCTURE OF THE SEED COATS OF FOLYGO- 
NACEHI. 
BY EMMA SIRRINE. 
Much work has been done on the structure of the seed coatsi 
'Of different orders of plants. The objects of studying the seed 
coats of plants microscopically are two-fold. Firsts to> heip' 
detect adulterated foods, etc. , and in this respect the study has 
been of very great value. Second, to aid in the distinction and 
Jseparation of species. 
From a systematic standpoint the characters afforded by the 
rstructure of the seed coats have been found wanting. In some 
instances in the order Polygonacece marked differences in struc- 
ture are present in some species; in all, however, the same gen- 
eral structure occurs. 
Among the European investigators who have studied seed 
coats in general may be mentioned ^H. Godfrin, Harz, Lohde, 
Schleiden and Vogel, U. Dammer and Moeller. But few Amer- 
icans have taken up this work. Of these, several papers by L. H. 
Pammel, and one by P. H. Rolfs, on the structure of seed coats 
of Malvaceae, may be mentioned. 
L. H. Pammel has shown that in the seed coats of the genus 
Ewphorbia some marked differences occur. In Euphorbm poly- 
gonifolia gelatinous spiricles were found when moistened with 
water; this also occurs in Euphorbia Geyeri, but not in E. Preslli 
and E. maculata. In the seed coats of leguminous plants the 
*H. Godfrin: — Etude bistologique sur les teguments seminaux des angiospermes; 
Adv. Sc., Vol. 39, 1890, page 328. Harz: Landwirthschaftliche Sanienknnde, Berlin, 
1885. Lobde: Ueber die Entwickelunggescbicbte und der ban elniger Samencbalon, 
Naumberg, 1874, page 34. Scbleiden und Vogel; Ueber das Albumen Insbesondere der 
Leguminoseen. U. Dammer in Engler and Prantl, Pflanzfamillen III Tbiel, pages 6-7. 
Mceller: Mikroskopie der Nabrugs und Geunssmittel ans dem Pflanzenreicbe, pages 
119-124. Pammel: On tbe Structure of tbe Seed-coats of tbe genus Euphorbia, Tran- 
sactions St. Louis Academy of Sciences, Vol. XIII, p. Rolfs: On tbe Structure of tbe 
Seed-coats of Malvaceae, Botanical Gazette, Vol. XII, p. 33. On tbe Testa of some 
Leguminous Plants, Bull. Torrey Bot. Club. Vol. XIII, p. 17. Hanausek: Die Nab- 
rungs und Guensmiotel aus dem Pflanzenreicbe. Haberlandt: Sitznngsber. d. k. 
Akad. d W. zu. Wien. Vol. LXXV., 1877, p. 33 separate. 
