A CHRONOLOGICAL LIST 
The subjoined list is intended to be a catalogue of all the 
known species and important varieties in the Vascular Cryptogams 
growing without cultivation in the New England states; their 
chronological arrangement as regards best time for collection ; and 
a memorandum, which with the assistance of references to their 
description, etc., shall assist the collector in obtaining them. 
The best time for collection is usually just before the spores 
mature, but with some species, notably in the genus Dryopteris, 
the condition of the indusium is also be considered. In the case 
of some of the Equisetacece the fertile stems are in bad condition, 
when the sterile become fully developed. Species in Filices having 
dimorphous fronds, mature the fertile fronds so late that the ster- 
ile ones are not fit for collection, or the fertile are mature before 
the sterile are well developed. In such cases dates have been 
given for both. Some species mature their fertile fronds quite 
early but continue to produce a few scattering ones until late in 
the season. In this event only the earlier and more abundant are 
considered in this list, Some species, as Asplenium viride and 
Asplenium montanum are in fair condition at ail seasons, while oth- 
ers in Equisetum and Botrychium have a fruiting season of not more 
than a week or ten days in duration, 
The development of the earlier species is of course affected to 
some extent by the difference in seasons, but when it is considered 
that the fruiting season of no species has very narrow limits, that 
the variation in time of maturing in successive years is but small, 
and that the object is not usually to collect plants in quantity, it 
becomes evident that an everage date may be selected which is 
quite likely to serve all purposes of the collector. 
Differences of latitude are also to be considered, as is also the 
proximity to the coast. For such species as grow in eastern Mas* 
