Madrean Sky Island Flora

[Silas_Sancona]

Spent a near perfect Sunday exploring one of the crown Jewels of both Arizona and the greater Southwestern U.S.  While i debated on whether or not to place the " plants encountered" portion of this part of this year's " Emerald Desert " Series in the Flores Del Sol thread, because there was much more to see down there than just flowering things, decided to create a separate thread. 

Despite the abundant rainfall down there this summer, most of the annual stuff / grasses in the lower elevation areas were already starting the drying process so missed out on this year's edition of  " Monsoon Magic  Plants " in those areas.  Further up in elevation, still plenty green with a fair amount of stuff in bloom.

For those not familiar with the region,  The isolated groups of mountains here and in southern New Mexico represent the northern fringe of the Madrean Pine / Oak Woodlands, and Tropical / Subtropical Coniferous Forests that extend north/south along the Sierra Madre Occidental / Mexican Plateau just across the border in Sonora and Chihuahua. While connected to each other when the climate was cooler and wetter, each group of " Sky Islands " serves as a refuge for various plants and animals which have survived various climate cycles. In Arizona and New Mexico, each " Island " can contain a different assortment of both temperate and tropical flora with a gradual lean toward each major biome depending on whether one heads south or north. Because of this, one can find certain things like our native Coral Tree, Erythrina flabelliformis, species of Jatropha, or even Tillandsia growing on a south facing slope, while higher up where it is cooler / wetter, one may find Ponderosa Pine, Maples, Aspen, and other things one might find further north in the Rockies, Sierra Nevada,  or even Canada.

Will start this thread with a " flowering things, ferns, etc" portion, and a second section devoted to the major groups of trees of Madera Canyon.  As mentioned, while there was plenty to see, there is plenty that i wasn't able to track down on this visit..  Regardless, very neat seeing such a varied assortment of plants in such a unique place which, to me exudes elements of landscapes and terrain that mirrors the mountains directly east of San Jose, the Sierra Nevada, and/ or mountains around Southern California. Nice to stand among subtropical Pines again as well.

As mentioned , a touch late for 95% of the summer season annuals in the low elevation areas outside the canyon but, a found couple things.

Desert / Thurber's Cotton, Gossypium thurberi.  While frost can keep them short here in AZ, these can reach 12-15ft in height further south in Sonora or where frost won't cut them down regularly here. This is one of the plants which creates " Traditional "  fall season color in Southern Sonora when the leaves turn various shades of Red and Orange. Flowers look like a Hibiscus and change from Cream to Purplish or Rosy Pink.





Evolvulus arizonica, AZ Blue Eyes.




Heading into the Canyon, more color, though you can tell the dry season has started.

Morning Glories.. Ivy leaved ( I. headeracea = Blue ) and Trans Pecos ( I. cristulata = Red )













One of a few DYC's < Dang Yellow Composites > encountered in the Canyon.. Possibly a species of False Golden Eye, Heliomeris, but could be a species of Bidens ..or something else.




Knew these occurred here but a little surprised to find them at a relatively low elevation..  Cut-Leaf Coneflower, Rudbeckia laciniata.. Also common in N.E'rn Kansas. Did not remember the flowers being fragrant.. Strong Chocolate scent.








Erythrina flabelliformis, Southwestern Coral Tree.. a very obvious link to the tropics. Where they grow in S. AZ, regular hard frosts/ freezes keep them trimmed to small / medium -sized bushes. Further south and free of frequent cold damage, they can attain heights of 20-35ft. Flowers appear on naked branches in June, right before monsoon season rains begin. will start to turn a rich gold or brownish over the next few weeks as Monsoon season closes out. In S. Sonora, these provide a major part of the " fall color " in the dry forests there.










Scarlet Bouvardia, Bouvardia ternifolia



Mirabilis longiflora



Rivina humilis, Pigeonberry / Rogue Plant.. Another connection to the tropics.



AZ Sunflowerweed, Tithonia thurberi,  Just past bloom, but can see how tall these get.. Easily over 6ft.



Bidens alba ( same " weed " that occurs in yards in Florida ) and another DYC, lol..





Perhaps the only Maidenhair Fern species in AZ, Black Maidenhair Fern, Adiantum capillus - veneris




Higher elevation areas along Madera Canyon..

Desmodium batocaulon, San Pedro Tick Trefoil





Not flowering, but not expecting to find a Lupine sp. growing here, let alone in the fall. Is apparently listed as threatened. Huachuca Mountain Lupine, Lupinus huachucanus



Another connection to the tropics, ...more so the mountains of Mexico, Hartweg's Groundsel, Rolandia hartweggii. Surprised this isn't already in cultivation. Flowers might not be much to look at but big leaves are quite tropical- looking.





🎵 Hello my old toxic friend.. I guess it was time we met again.. 🎵   Western Poison Ivy, Toxicodendron rydbergii . This stuff, well, it's toxic cousin, Poison Oak has a strange way of ending up on me, even if i stay several feet away from it.. No obvious signs this encounter will leave me scratching night and day, so that's good, haha..



Schott's Yucca, Yucca schottii  and -possibly- Agave Shrevei.. but not 100% certain.  Imo,  this specimen doesn't clearly resemble Agave palmeri  i've seen.. or ones i have at the house that are around the same size. Tried to locate a larger specimen but couldn't  -or i didn't look around enough. Growing in shade could obviously change how a young A. palmeri would look.






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[Silas_Sancona]

Continuing on...

Coral Bells, Heuchera sanguinea, Most people have probably grown these at some point in their plant growing career. Always neat to make the connection between the plant you'd see in a garden center, and where it originates.








Pinewoods, Geranium caespitosum ( = Pink flowers ), and Richardson's Geranium, Geranium richardsonii ( = White Flowers ). Second species is a fairly good indicator you're above 5,500ft in elevation. Very common in the Rockies and Sierra Nevada. Pinewoods Geranium is slightly more restricted... mainly found in the Rockies, AZ and New Mexico high country. Disjunct population can be found in the mountains of far northern Baja.





Not something you'd expect to find in bloom ..in the Fall.. ( Most species are spring flowering ) Rocky Mountain Larkspur/ Delphinium, Delphinium scopulorum. Despite the name, appears the species is restricted to the mountains of Southern AZ, and Gila Mountains in New Mexico.








Common Bracken Fern..






Nodding Onion, Allium cernuum.  Rockies, Pacific Northwest/ B.C.,  Appalachian Mountains / upper Midwest. Is apparently edible ( some Allium species aren't. Some Bulb-forming plants that look like Onions can kill you.. ) and used as a substitute for traditional, store bought Onions or Chives.



First Orchid observation in Arizona:  Huachuca Mountain Adder's Mouth, Malaxis corymbosa. Not much to look at ( What tiny green flowers it produces are long gone ) but gives you an idea of the incredible diversity found within the Orchid family, and provides a tantalizing hint of the far more exotic looking, but still fairly hardy Orchids that can be found just a couple hours south in the Sierra Madre in Sonora. Restricted to S. AZ / Mountains of N. Sonora, with a disjunct population in the Sierra de la Laguna mountains of far southern Baja. There is at least one species of Bletia that occurs in the Santa Rita Mountains / Madera Canyon/ nearby mountains near the U.S. Mexico border..

[Silas_Sancona]

...Onto what defines Madrean Woodlands  ..the Trees..

Further south in Sonora, elements of the tropics define lower elevation " forests ". As one heads higher up the mountains, forests are dominated by a rich diversity of tropical Pines and Oaks. Mexico itself is a diversity hot spot for both families with several dozen species of Oak being found there. Some look like any typical Oak you might find in California, Texas, parts of Europe, or back east, while others have huge leaves and could be mistaken for something like a Ficus, Magnoila, or Sea Grape when first encountered.

One of the most recognized of the large leaved, Mexican Oaks is Quercus tarahumara, an endemic species to mid elevation areas in the Sierra Madre not too far from the U.S. / Mexico border. It alone demonstrates how un- oak like some of the Tropical Oaks can look yet, it is just one of several big leaved species that can be found down there. Further north, 3 species of " tropical " Oak extend into Arizona.

While some would say a Pine is a Pine, those from warmer, more tropical regions typically exhibit longer needles and more a open growth pattern than species from higher latitudes.

In the northern reaches of Madrean Pine/Oak Woodlands, you get a mix of temperate and tropical species from both families, depending on which " island ' you happen to be in.  While they evolved under different influences, the Oak and Pine / Oak woodlands in California could be considered a far distant echo of the Madrean version of this habitat. In some cases, individual species of Oak and Pine there have ties to relatives in Mexico or Southern Arizona.

While you don't see many ( ..or any  ) examples of them in Southern AZ.  in Sonora, ..and further south... the Madrean Pine/Oak woodlands are where you'd find a number of the Orchids, Tillandsia / other Bromeliad families, and Cycads ( Dioon, in Sonora ) that occur there. 

Other " tropical " plants like Asplenium,  Anthurium, Begonia, and Pepperomia  reach their northern limits in parts of this habitat as well. Somewhere in between the lower, dry tropical woodlands, and the cooler, and wetter Pine/Oak woodlands is where several of the Palms native to western and southwestern Mexico would be encountered as well.  Colder winters / drier summer rainy seasons are likely the only things keeping some of these more exotic things out of the mountains in Southern Arizona.  Could that change if winter frosts/ freezes, became less restrictive / Summer rainfall became abundant enough in future decades? 

Another component of this habitat, at least in Arizona and New Mexico, is Pinyon / Juniper woodlands.. a sort of bridge between boreal and subtropical forests..  which separates the deserts / dry grasslands at the lowest elevations, from the moister Pine/ Oak woodlands above. In Sonora ( and possibly Southern AZ ), Thornscrub / Mesquite woodland would replace Pinyon and Juniper in lower areas between the deserts /Grassland areas, and Dry, Tropical Deciduous Forests / lower reaches of Madrean Woodlands.  In some cases, the transition between each woodland habitat is rather abrupt, while very gradual in others. Madera Canyon offers up a great example of both..  At the opening of the Canyon, one can see the vague " Bath Tub Rings"  of each woodland type, while Alligator Juniper slowly fades out as you climb up in elevation in the Canyon.

Alongside the Madrean Woodlands,  Riparian corridors that follow streams and rivers out of the mountains are important highways for plants. It is in these areas where tropical stuff would find a foothold at lower and drier elevations in warmer times, then slowly expand up slope or away from that ideal environment if favorable conditions continued to expand. The reverse would occur if heading back into an Ice Age. In between? a mix of species from both major climate regions.



The Oaks... 6 to 8 species in Madera Canyon.

AZ. Blue Oak, Quercus oblongifolia.  Look familiar?  For everyone in California, there's a reason..  While it may be more distantly related to Blue Oak, there is evidence Quercus englemanii in southern California, and this species are directly related, separated only when the deserts expanded and isolated both species.  AZ Blue Oak has been trialed in California as a better option for cultivated landscapes due to its better tolerance to drought, higher temperatures, and summer watering ( in residential landscapes ) California's native Blue Oak, and some other native sp. don't tolerate being irrigated as well during the Summer dry season. Some fantastic specimens in the Canyon.

One of the specimens in this section of the Canyon is labeled as AZ White Oak. If you look at the two sp. on iNat, i'm fairly certain that tree is mis-labeled and actually a Mex. Blue Oak. Pictures of the Acorns / Leaves were from the labeled specimen.













Silverleaf Oak, Quercus hypoleucoides.  Mid elevation species and very common as you get higher up in the canyon. Bright, silvery- white fuzz on the undersides of the leaves is very attractive. While still rare in the Nursery Trade, supposedly has done quite well where trialed in California and the Pacific Northwest.





Color of new Foliage...








**AZ. White Oak, Quercus arizonica ..and/ or Gray Oak, Quercus grisea These two look similar and i'm not 100% confident on a bulletproof ID.








These two pictures may be Q. rugosa..









**Netleaf Oak, Quercus rugosa.  Arizona's only large-leaved, tropical Oak species. Some break up the species between two forms: a shorter, smaller leaved form from the northern part of it's range, and the larger leaved form in Mexico. Like the last two sp. somewhat tough to get a perfect ID on this, though the larger, spatulate-shaped leaves helps it to stand out more.  Another " Southwestern Oak " that has been successful where trialed in California / Pac. Northwest. Fairly sure this specimen is a legit. representative of the species.



** Because all three occur close together in the same areas, it is possible hybrids exist between them making leaf size/ shape variable.

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[Silas_Sancona]

Pinus englemannii, Apache Pine / Arizona Long Leaf Pine. 

Perhaps the most important Pinus species in the AZ Sky Islands, often called the western counterpart of the Southeastern U.S. Pinus palustris, ( Long Leaf Pine ) which it resembles in general appearance, size of the needles ( up to 18in long in P. engelmannii ) and that it goes through a grass stage after germination, and forms a deep Taproot ...both adaptations giving the species the ability survive fires and an advantage when regenerating afterwards. It is considered the keystone Pine species in both Arizona and S.W. New Mexico, often growing in pure stands, or taller than some of the other Pines here,  but grows among several similar looking pines in Mexico.  While younger specimens are often green, Foliage on older trees can take on an attractive bluish tone. Like many of the subtropical pines, hardiness is only into the teens ( zone 8 ).













Pinus leiophylla, Chihuahuan Pine, Tough to get good pictures of these but differences between it and P. englemannii are pretty obvious.. Smaller needles, different shade of green, and cones are much smaller. Response to fire damage mimics Canary Island Pine in that if the crown is destroyed, the trunks of P. leiophyla can re sprout and go on to form a new crown. Neither species is directly related and the adaptation is an example of convergent evolution..  Similar to how many Euphorbia in Africa fill similar roles in their environment as Cacti do in the Americas.  Species grows from Arizona down to Oaxaca in Mexico.





P. arizonica or englemannii cone on the left, P. leiophylla on the right.



P. englemannii on the right, P. leiophylla on the left.




Southwestern White Pine,  A little surprised to find some of these in the Canyon.. Figured i'd have to reach 7,500-8,000ft to observe this species. Small, somewhat thin-looking needles and those long cones define the species. Related to Sugar Pine.











Border / Mexican Pinyon, Pinus crembroides




Alligator Juniper, Juniperus deppeana  One of the most distinct trees in the Southwest... When looking at individual trees in a grove of Junipers, a good rule for pick out Alligator from any others that might be growing nearby is looking for the " 'Gator skin" bark pattern..  No other Juniper has it.  Some great specimens of the species in the lower portion of Madera Canyon. Did not realize they can grow in mixed stands with Oak, Madrone, and the local Pines further up and reach very impressive heights, for a Juniper. Ripe fruit is said to be edible, though maybe not the most flavorful.












Arizona Madrone, Arbutus arizonica.  Always wanted to see the counter part to the Madrones i grew up around back in California. Arizona's species is somewhat different.. Bark isn't quite as smooth, leaves are smaller / a bit narrower, and overall height is... at least in specimens i encountered,  shorter.  Imagine there are taller specimens higher up, or further south in Mexico ( Range extends to roughly Aguascalientes, if not further southeast there ).









Arizona Sycamore, Platanus wrightii.  Next to Cottonwoods, Sycamores are an iconic, stream side tree in the southwest / other parts of the country. While many AZ. specimens might not attain the giant dimensions some specimens do back east, there are impressive specimens to be found in the state. While they look similar, Foliage shape / size is different in P. wrightii compared to CA. Sycamore ( P. racemosa ) Air is filled with that same, earthy scent when standing below P. wrightii  though.










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Neck breakers...
Q. oblongifolia



Pinus










...And a Ferocactus.. ( F. wislizeni )  ..Just to remind the traveler where you're at.