122 
IOWA ACADEMY OP SCIENCE 
that this 0. Larnarchiana is different from the form whose history we 
have tried to trace, and which we believe was originally a native of 
Virginia; hnt the 0. LaniarcMana now growing wild on the coast north 
of Liverpool, England, and wdiich must have come' from the early in- 
troduction (according to records which show that it has been growing 
abundantly there since at least 1805) is found from cultures to be very 
closely similar to the Texas form from which originated the plant in 
DeVries’ cultures. 0. grandiflora Ait. has also ]3een shown, from 
statements of Bailey, and my own cultures, to be growing wild in the 
same English locality, and intercrossing freely with 0. Lamar cMana 
and certain of its mutants. It seems probable that both species have 
been naturalized here since early in the 18th century. 
The fact that the small-flowered forms are self -pollinating, gives them 
a much better chance in the struggle for existence than the large-flow- 
ered oi^en-pollinating species because they have a better opportunity to 
set seeds. This probably accounts for the fact that the small-flowered 
forms are now more wide-spread and prevalent in Europe except in 
locations sparsely covered with vegetation, such as sand dunes, where 
the open-pollinated forms can aggregate in large numbers. It also 
probably explains the more or less complete disappearance of the large- 
flowered forms from eastern North America, since the introduction of 
civilization, for with increasing enemies the amount of seed production 
may fall below the minimum necessary for the preservation of the 
species. 
iMissouri Botanical Garden. 
• ' niST OF HISTOKICAL WORKS CONSULTED. 
1623. Bauhin, Caspar. Pinax Theatri Botanici. Basil. 
1627. Alpin, Prosper. De Plantis Exoticis. Venice. 
1629. Parkinson, John. Paradisus Terrestris. London. 
1640. Parkinson, John. Theatrum Botanicum. London. 
1651. Hernandez, Francisco. Rerum Medicarum Novae Hispaniae Thesaurus. 
Rome. 
1651. Hernandez, Francisco. Nova Plantarum, Animalium et Mineralium 
Mexicanorum. Rome. 
1651. Bauhin, John. Historia Plantarum Universalis. Vol. II. Ebroduni. 
1665. Jonquet, Dionysius. Plortus Regius Parisiensis. 
1669. Morison, Robert. Hortus Regius Blesensis. London. 
1677. Hoffman, Flora Altdorfhna. 
1680. Morison, Robert. Plantarum Historiae Universalis Oxoniensis. Oxford. 
1686. Ray, John. Plistoria Plantarum. London. 
1687. Hermannus,Paulus. Horti Academic! Lugduno-Batavi Catalogus. Ley- 
den. 
