1909]  Moore,— Epilobium alpinum and E. Hornemanni 143 
'[' release in his revision or in the seventh edition of Gray's Manual, 
for instance,! the flowers are white,’ and the leaves are light green. 
The leaves have also been described as thinner than in E. Hornemannt 
Reichenb., but it is quite likely that this effect is optical, due to the 
greater translucency of the coloring matter. At bes: it is a very un- 
certain character, as the apparent difference is so slight that the leaves 
of E. Hornemanni may become thinner on pressing, if they are not 
sometimes so to begin with. In the last named species the flowers 
vary from rose or lilac to deep purple, the leaves being darker and 
often suffused with purple.? 
‘In view of these facts it seems best to treat one of the species as a 
color form of the other, but before doing this it is necessary to make 
sure that E. alpinum, which is obviously the older name, has been 
correctly interpreted. In the Species Plantarum * Linnaeus says 
nothing about the color of the flowers, but refers to a description in 
his Flora Lapponica ë which reads as follows: 
EPILOBIUM foliis ouato-oblongis integerrimis. 
? Chamenirium alpinum alsines foliis. Scheuch. alp. 59. 
a Plantulam hane bis vel terin Alpibus lapponicis legi, preesertim 
ad latera earum, preecedentibus congeneribus mixtam. 
8 Caulis simplex, vix dimidii digiti longitudine, parum 
rubescens. 
Folia opposita, inferiora minora ouata, superiora maiora 
& magis oblonga, integerrima omnia. 
Flores duo, rubri, parui, caulem terminantes, petalis emargi- 
natis purpureis. 
Conueniunt hee & antecedentes dus (148.149.) florum 
corolla parua, petalisque bifidis & sequalibus. 
Linnaeus likewise refers to Epilobium foliis ovalibus, superioribus 
attenuatis L. Flora Suecica, 111 (1745), which throws no light on the 
subject of color. From what has gone before, it would appear plain 
that it was E. Hornemanni which was meant and not the white-flowered 
form as has been supposed, but the matter is not quite so simple. 
Although this was apparently the older view (for if we turn to Flora 
1 Cf. also E. lactiflorum Hausskn, Monographie, 158; Gray Mannal, ed. VI, 189 (1890). 
2 According to Gray Manual, ed. VII, 597 (1908) also “ pinkish.” 
3 Mr. H. H. Bartlett assures me that it has been demonstrated in a number of analogous 
cases that it is the same purple coloring matter as in the flowers which makes the leaves 
darker or purplish. 
4 р. 348. 
5 p. 114 (1737), 
6 Note the uncertainty. 
