1887. | BOTANICAL GAZETTE. 17 
species; and those of North America have not been neglected. But sev- 
eral are still in doubt or obscurity; and few of them, even those of the 
Atlantic States, have been sufficiently studied alive, although this is nearly 
indispensable. Professor Foster, according to the wishes of botanists who 
recognize the need of the undertaking and his unequaled fitness for it, is 
disposed to undertake an elaboration of the species; and he has appealed 
to me for aid in the difficult matter of procuring ripe seeds or living 
roots of certain American species and forms which are not in his exten- 
sive collection. He particularly wants I. tridentata and I. tripetala from 
the Atlantic side of our continent, I. Hartwegi, I. Beecheyana, I. macro- 
siphon, as well as two recent species of Watson, I. tenuis and I. bracteata, 
from the western portion. For these and for any other rare or local 
forms—for all wild Irises, except our common eastern species—an appeal 
is now made. Seeds and roots contributed to the botanic garden of our 
Cambridge will be thankfully received and cared for, and a goodly por- 
tion promptly transmitted to Professor Foster in Cambridge, England, 
where we may expect them to be fully investigated. For, in a letter to 
me Professor Foster writes, “I do not like to come to any conclusion 
about a plant until I have had it under my eyes alive, and know its whole 
story from seed to seed again. I mean I do not feel that I have really got 
hold of the form until I have done this, though of course one can learn a 
good deal short of that. Hence I am anxious to get hold of living plants. 
Your North American forms are most interesting when the morphology 
and geographical distribution are worked together, and in connection 
with the Asian forms. 
Note that seed, to be of any good, should be thoroughly ripe; and 
that living roots are in best condition for transmission in early autumn. 
ASA GRAY. 
On petiolar glands in some Onagracex.——At a recent meeting of the 
Academy of Natural Sciences of Philadelphia, Mr. Thomas Meehan 
remarked that stipules were unknown in Onagracez, but in Ludwigia 
(Isnardia) palustris there were two minute conital gelatinous glands, at 
the base of each leaf, that appeared to be stipular. They existed in series 
of specimens representing the Atlantic and Pacific coast, and from 
Europe, those from California being larger than in specimens from other 
localities. They are found in all the species of Ludwigia and Juggivea 
that he had been able to examine. In these they appeared petiolar rather 
than stipular. In the dried specimens of Circea a dark spot indicated 
the position occupied by the glands in other species. They mostly varied 
in form and exact position with the species, and only for having been 
wholly overlooked by describers might have aflorded some good specific 
characters. The discovery he regarded as interesting, as confirming the 
views of those botanists who had brought Turneracew, in which the peti- 
olar glands were known to exist, in close relation with Onagrace. 
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