There are about 5 species of hornworts in British Columbia, with their numbers increasing as you head sound. Hornworts are ephemeral things that seem to only be prominent (or as prominent as a 1cm plant can be) in the spring when their large horns/sporophytes are developing.
Where and when to look for Hornworts
In coastal British Columbia, hornworts seem to show up in February and March and loiter until early summer around seeps over thin, finer soil and rock. There are also records all over the west for agricultural fields-- presumably soils of the moisture retentive "clod" type.
What you need to identify Hornworts
Ideally you will have fertile material with mature spores. You will know you are at the right stage when the long sporophyte begins to dehisce and reveal the spore mass within. Barring that, you can look for little bulbils (asexual propagules) on the underside of the thallus. The shape of the thallus and the abundance and form of the protuberances can also be helpful. The three genera of this region can be distinguished based on the presence of the bulbils (Phymatoceros bulbiculosus) and, in the species lacking those bulbils, the colour of the spore mass: yellow in Phaeoceros and black in Anthoceros.
Hornwort ID resources
Hornwort Databases
A final comment about collecting
There are only about 50 records of hornworts in herbarium collections for the province of British Columbia. Their diversity, distribution, ecology, phenology et al. are not well understood in our region, so any records for this group are worth collecting provided the population is vigorous and you have permission/permits to collect where applicable. Below you can see @jstraka 's recitation of a helpful rule: "The rule of thumb I have heard for collecting (at least for plants) is the "1 in 20" rule - The further comments below by @david1945wagner clarify the rule "It is a rule of thumb that you should find at least 20 individuals before collecting just 1. There should be 40 present to collect 2. It's a rule of thumb, meaning to be applied on a case by case basis. If applied strictly, it might result in populations of a rare species reduced to 19. With lichens or bryophyte colonies it may mean to take only 5% of the patch or thallus." The full write up of the rule can be found down the page here in a 1991 issue of the Plant Science Bulletin from the Botanical Society of America.
You should collect and send hornworts that meet these criteria to your regional herbarium. If you have questions about this, feel free to contact me. Instructions for submitting material to the UBC Bryophyte Herbarium, for example, can be found here.
Comentarios
@bstarzomski @dbltucker @fmcghee @bradenjudson @david1945wagner if you have more resources you think should be added here please post them and I will incorporate into future edits.
These are all wonderful- thanks @rambryum
Fantastic! Can't wait to go hornwort hunting in the spring.
Thanks for all these fantastic resources. The rule of thumb I have heard for collecting (at least for plants) is the "1 in 20" rule - if you can find 20 of them in a population, it's probably safe to collect one.
The 1 in 20 Rule is one that I originated along with at least two other groups of botanists independently about the same time. It is not, as mentioned above, that if you can find 20 it's probably safe to collect. It is a rule of thumb that you should find at least 20 individuals before collecting just 1. There should be 40 present to collect 2. It's a rule of thumb, meaning to be applied on a case by case basis. If applied strictly, it might result in populations of a rare species reduced to 19. With lichens or bryophyte colonies it may mean to take only 5% of the patch or thallus. My proposal first appeared in the newsletter of the Native Plant Society of Oregon and reached a wider audience in the Botanical Society of America's publication: 1991. The "1-in-20 Rule" for plant collectors. Plant Science Bulletin 37(2): 11.
@david1945wagner Thanks for clarifying! Makes sense.
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