Hoya Obscura Elmer ex Merrill ex Burton
My decision to write about Hoya obscura for Hoya of the month is due to a memorable discovery late one evening in Carol Noel’s greenhouse. As we were fumbling around in the dark, going up and down the aisle looking for the light switch, I kept catching a whiff of an incredible scent! Once we had light I could not stop until I located the source of the fresh, clean, and very strong fragrance. The source turned out to be very tiny flowers on H. cv. Sunrise, a cross between H. lacunosa and H. obscura. I decided to research one of H. cv. Sunrise’ parents – H. obscura.
Hoya of the month - H. obscura - March 2006
A.D.E. Elmer discovered Hoya obscura in July 1916 at Irosin (Mt. Bulusun) Province of Sorsogon, island of Luzon, Philippines.
Adolph Daniel Edward Elmer was born in 1870 in Vandyne, Wisconsin, and died in a prison camp in Manila, Luzon, Philippines, in 1942. He was educated at Washington Agricultural College and received a masters degree from Stanford in 1903. He settled as a plant collector in the Philippines in 1904, first working for the Bureau of Science. He was the editor of the Leaflets of Philippine Botany, in which more than 1500 new species were described. Because Elmer failed to include Latin diagnoses or descriptions for names he published after 1934, about 50 of his specimens were not validly published
The isotype specimen, number16719, is on record at the Nationaal Herbarium Nederland.
The link to the site is http://145.18.162.53:81/c8. Click on the All Collections link in the left menu bar. Type HOYA in “Genus” and click Search. There are entries for many different hoyas in the resulting page.
Edited to say I don't know why the hyperlink is not working! Try this one: http://www.nationaalherbarium.nl/virtual/
This message was edited Mar 28, 2006 11:50 PM
Publication
H. obscura Elmer was first mentioned, in name only, as a probable synonym for H. gracilis (wrong!) in ENUMERATION OF PHILLIPINE FLOWERING PLANTS Vol. 3, 1923.
Hoya obscura was published as a new Hoya species by Adolph Daniel Edward Elmer in LEAFLETS OF PHILLIPINE BOTANY Vol. 10, page 3586 (1938)
I lost three weeks of research time wondering and worrying about the reason Christine Burton later published Hoya obscura in The Hoyan Vol.8 #1 –Summer 1986.
After much more reading I finally found the answer. In The Hoyan, Vol. 7, Number 3. it is mentioned that the 1938 publication of H. obscura by Elmer was published in English three years after requirement to publish in Latin was adopted by the International Nomenclature Convention. The clue, which I only now understand, was included in my introduction.
(Because Elmer failed to include Latin diagnoses or descriptions for names he published after 1934, about 50 of his specimens were not validly published.)
Since the species had not been validly published under any other name Christine Burton proceeded with the valid publication of H. obscura in Latin.
We won’t even get into the EX Merrill part of this, as I will end up writing an entire book.
Taxonomy
H. obscura is classified in Hoya Section I - Otostemma.
Hoya known to belong in the Section I – Otostemma:
H lacunosa Blume – the “type” plant for this section.
H. lacunosa Blume var. pallidiflora Hook
H. pusilla Rintz
H. obscura Elmer ex Merrill ex C.M. Burton
Characteristics of the Otostemma section:
Small flowers, corollas usually revolute, corona lobes usually boat shaped, more or less radical, slender, without channels beneath; pollinia translators winged.
Description of H. obscura
In its native habitat H. obscura is a tangle forming epiphyte. There are said to be many clones of this plant. The leaves may vary in size and somewhat in shape on the same plant, and may vary between the different clones, however all are very easily recognized as H. obscura. When grown in bright light the leaves will take on beautiful reddish tones,
The visibly veined leaves are smooth as are the pedicels and peduncles of the inflorescence.
Photo generously provided by Christina Karlsson
The flowers are small, very fragrant and vary in color from cream to many different shades of pink.
Edited to credit Christina for this and all of the beautiful flower photos to follow.
This message was edited Mar 28, 2006 11:06 PM
This message was edited Mar 28, 2006 11:14 PM
Here is an example of H. obscura flowers of a darker color.
Hoya obscura flower photographed by Christina. Lovely cream colored blooms! H. obscura has been known to bloom different flower colors on the same plant, the color depending on the varying degree of light.
Edited to add more information!
Not only is the color of the flower of interest in this photo, but also note the number of rings on the rachis.
For the newbie’s: The rachis is the plant part between the peduncle and the pedicels of the flower. Each ring on the rachis represents a new bloom formed from the same peduncle.
So obviously the peduncles of H. obscura are persistent.
This message was edited Mar 28, 2006 11:12 PM
A little about the Geography of Luzon
Sorsogon, in the Bicol Region of Luzon Island, is home to Bulusan, an active stratovolcano, which has erupted at least 13 times since 1886, most recently in 1988.
Bulusan Volcano is located at the south central part of Sorsogon Province. It covers a surface area roughly 400 sq. km.(approx 248 sq miles) and towers to about 1559 m. (approx.5,114 ft.) above sea level. The volcano forms part of the Bicol Volcanic Chain, which stretches from Camarines Norte in the north to Sorsogon in the south. The chain, sometimes called volcanic belt, is composed of active and geologically young volcanoes most probably related to the Philippine Trench.
Irosin lies at the foot of Bulusan Volcano, the tail end of the Sierra Madre Mountain Ranges at the southern tip of Luzon. The town rests in a caldera; the valley floor is approximately 4,105.321 hectares. The Bulusan Volcano and several other mountains almost surround the wide valley floor, making the town the only landlocked municipality of the province.
Irosin has a very irregular terrain characterized by the plain on the valley floor, secluded plains and valleys on the mountaintops, undulating hills and mountain peaks. The valley for which Irosin is famous is located at the floor of Irosin caldera.
There are some fabulous photos of Irosin on these websites: http://nonsenseverse.typepad.com/photos/philippines/img_0494.html and here http://irosin.ph/gallery/
Looks like a great place to vacation!
This message was edited Mar 28, 2006 11:28 PM
Climate – Temperature and Humidity
The climate in Irosin belongs to the Type II of the Corona System, the classification of Philippine climates. The climate is tropical wet with a short dry season. Northwest Monsoon and Southwest Monsoon are the main air streams influencing the climate pattern in the municipality. Irosin experiences rains almost year round. Rainfall is observed and registered at an annual average of 212 days a year.
The annual average temperature registered is 80.24 degrees farhrenheit.
May is the hottest month with a mean temperature of 82.40 degrees Fahrenheit while February is the coldest with a mean temperature of 77.63 degrees. The annual relative humidity is 83%; December is the most humid month at 85% while April and May are the driest month at 80%.
Soil
The soil type in the municipality of Irosin is of volcanic origin composed mainly of alluvial deposits ranging from sandy loam to silt loam. (Alluvium is young sediment made up of freshly eroded rock particles that come off the hillside and have been carried by a stream.) Of the 6 types of soils found in the area, all are moderately to excessively well-draining soils.
BRAVO!! BRAVO!! BRAVO!!
Grrrrrrreat indepth study, Susan. Wow, you guys are really terrifice with your studies and profiles!! H. obscura is one of my favorites...along with her hybrids and relative...SOOOoo fragrant and happy!!!
Carol
And so, in closing..........
H. obscura is going to thrive in a consistently warm and humid environment. When grown in very bright light the leaves will take on beautiful red tones.
It is also said to grow well in artificifial light when provided the heat and humidity it loves.
Keep the soil evenly moist and very well drained. Don't let the soil dry out completely! I have had to start over from cuttings more than once.
Susan ........
who's next?
Susan, thank you so much for this information!!
These profiles are absolutely fantastic!
Do you have this info in a format that can be e-mailed? If so, I would love a copy!
You Rock!
Ann
I just love this forum.......
WOW, girl! Fabulous job!!!!! Thank you!!!
WOW!! GREAT JOB!! Thanks, Susan! If available, I'd love a copy, too!
WOW!!!! I feel like a genius just from reading this. So detailed. One question, why did Wilmer end up in a prison camp??? Hoya collectors are a little shady eh? Lol!! I'm hoping someone who understands can put all of the hoyas of the month into something that us non computer understanding people can link to. Maybe a thread. Is this already the case? Sorry if this is a not so genius question. Thank you so much Susan!
http://davesgarden.com/forums/t/566664/
Edited to say, I found that magical place for hoyas of the month....
This message was edited Mar 29, 2006 12:25 PM
This message was edited Mar 29, 2006 12:25 PM
A little history from WWII. Ten hours after the Japanese bombing of Pearl Harbor, on Dec. 8, 1941, the Japanese attacked the Phillipines. By Dec. 22nd the island of Luzon fell to the Japanese. I imagine A.D.E. Elmer was interred in a prison camp as a result of being in the wrong place at the wrong time.
Japan declared war on America and Britain with bombing of Pearl Harbor.
Great info., pretty pretty flowers..... 80% humidity...!!!! No wonder mine does not grow or bloom.... And the darn flower is just so pretty. Thanks Susan, great job...
Great job Susan.. Thanks for taking the time to research , and document all this information and share it with all of us. I really enjoyed reading it.
Patti
Good job Susan! Thanks for all the time spent doing this for us. Great article!
Matt
Awesome job, thank you!!
Blessings,
Awanda
And very helpful for newbies too. I learn so much just lurking and reading. Thanks very much (to everyone!)
Well done, Susan. I had wondered about the protocol on republishing plants which had been previously incorrectly published. BTW, I have an obscura I had for years, treated with a bad cheap systemic which made all the peduncles fall off, gave away, and reaquired from a friend who moved away. I've had it back now for about 9 months, it is a big, healthy looking plant, but no peduncles, even on new growth! It gets good light, near a southern window, and is well watered. Any suggestion?
Mark
Humidity?
A plane ticket to Hawaii? LOL!!
Had to come in and peak again, I just love the flower on this one.
Again great job Susan. Thanks so much